Tascam M-35 Operation And Maintenance Instruction Manual

Download

Page 1

TASCAM

TEAC

Audio

Mixer

Production Products

OPERATION /MAINTENANCE

Page 2

Page 3

IN'TRODUCTION T0 THE MODEL

The Model 35 is an audio mixing console designed to satisfy the requirements of modern multichannel recording. Many of the auxiliary mixing systems needed are built-in and can be re-routed to do more than one job. Fast, convenient and complete operation with can usually be accomplished without re-patching.

However, the process of multichannel recording

constantly changing, growing more complex an art with each advance in technology. Your signal processing needs may arrangement of subsystems. No console has ever been built so large and complete in that it could with one button. Someone come up with that unusual situation requiring "just one more mix". In order to copewith

solve every imaginable problem

or 8-track recorders

require a unique

its

routing

will always be able to

thesep

unpredictable requirements, patch points are provided throughout M -35.

As our mixing console becomes more flexible, the amount of available function increases signal path from mic in to line out straightforward. The requirements changed much routing for effects sends,

monitoring often overlooks the that would be immediately obvious to the rienced recording engineer. If you expect to find that "extra rnix" quickly, you must be prepared to study the layout of the M -35 thoroughly.

since the days of "mono", but the

can be hard to visualize. 'rhe beginner

al1 signal pathways on the

time needed to understand the

well. The main

still fairly have not

cue feeds, and stereo

significance of connections

expe-

Input module layout including back panel

In most instances, the physical arrangement of the controls on the top pane1 has very little to ule actually followed the order in which they are do with the sequence of electronic parts inside. wired, the module top The actual wiring order need to understand to use the M -35 successfully~

the information you We'll put the jacks on the top,

As an example, if the controls on an input

pane1 would look Iikethis.

switches and faders.

mod-

well as the

Page 4

While this arrangernent of controls rnight help the beginner to understand the flow of signal in the

rnodule,

StiII, the wiring sequence rnust be understood

ate.

would be very inconvenient to oper- diagrarns, rnother-board layouts and rnechanical

can be used successfully. So along with the docurnentation you

disassernbly inforarntion), we include

will need for service (schernatic

asirnplified

before the more cornplex functions of the M-35P electrical sequence chart called a block diagrarn.

This drawing shows al1 the controls, switches, arnplifying stages and connectors in their

proper order. Learning to read it will provide theanswers to any questions about what cornes where on the

inside. Even though the block diagrarn

cate what flexibility,

available in the way of extra circuit

can't explain why a connection or

can indi-

switch has been included, or suggest a standard

layout. In the following sections of this rnanual,

we will do our best to describe the

individua1 functions and controls of the M-35, and how they can be arranged in more than one sequence; but, your rnixing needs rnay be best served by an

ar-

rangernent of inputs and sub-systern connections

you work out for yourself. To begin,

we'll start with some basic inforrnation about sound and the nurnbering systerns used to describe

levels in and out of the equiprnent and

impedance-what the terrn rneans and how to dea1 with the details when you rnust connect frorn our gear to other equiprnent. Many aspects will be discussed in the rnost basic language we can use. There

a vast arnount of inforrnation available to the beginning sound rnixer but rnuch of it

not basic enough to be easily understood,

assurnes that the reader has an engineering or scientific background and wil "the rnath". Practical

"rules of thurnb" for the

be interested in

novice are not generally available. Sornething be-7'

Direct

from

subrnaster "Ta~e

inn*

solo

tween a picture of the outside of the unit and a complete rnathernatical

inside

needed. You don't have to build a mixer

frorn scratch, you

analysis of the circuits

just need to know how to

operate one.

However, some nurnbers are unavoidable. The M-35 rnixer does nothing connected to

quite a lot of sophisticated gear.

Mics, tape recorders, power amps, and

useful without being

loudspeakers al1 play a part in the process of rnixingl recording and each piece of gear has its own requirernents and problerns. We have tried to rnake this rnanual

as sirnple as technology will allow.

Each section or topic will give you some basic

instruction in the terrninology used in the

process of rnixing as well as a list of what plug goes into which

jack. Whenever possible, the scientific terrns have been related to understandable cornrnon references.

Understanding what isgoing on inside your

equiprnent will help you irnprove your sound. Think of this rnanual need al1 of what

not necessary to rnernorize find tirne to way you will be farniliar with

as a reference book. You won't

here to begin, and it certainly

it,

but do try to

read

carefully at least once. That

its

contents. If you

need the nurnbers, they will be there waiting.

Good luck with your sound.

Page 5

'THE

DB;

WHO, WHAT, WHY

No matter what happens to the signal while

being processed,

again by

human ear. So the process of convert-

will eventually be heard once

ing a sound to an electrical quantity and back to sound again must follow the logic of human hearing.

The first group of scientists and engineers to dea1 with the problems of understanding how the ear works were telephone company researchers, and the results of their investigations form the

foundation of al1 the measurement systems we use in audio today. The folks at Bell Laboratories get the credit for finding out how we power, how quiet a sound an average person

hear, and almost

al1

of the many other details about sound you must know before with it

successfully.

judge sound

can

you can work

From this basic research, Bell Labs developed a system of units that of the system. Sound traveling on wires as

could be applied to al1 phases

electrical energy, sound on tape as magnetic energy, sound in air; anyplace that sound stored as energy until some future will again be sound,

can be described by using

the human ear-related system of numbers

is,

or has been

time when it

called "bels" in honor of Alexander Graham Bell, the inventor of the telephone.

What

a bel and what does it stand for?

loud? No,

only 6dB more sound. The unit quantities must follow nonlinear progressions to satisfy the ears' demand.

Remember, decibels follow the ears.

All other quantities of measure must be increased in whatever units necessary to satisfy the human

require-

ments, and may not be easy to visualize. Sound

in air, our beginning reference, the human ear to

4000Hz. Bell Labs measured this value to be

(young men) can detect

the least sound

1000

.O002 microbar, so we say OdB = .O002 microbars and work our way perceivable sound to humans" point. Here chart of sounds and their ratings in

up from the bottom, or "no

dB, using

.O002 microbar pressure change in air as our reference

for "OdB".

10,000

pnare druni

t140

nch

mic inride drum

inch

bass

drum

powr?Ilc voice

inch

Ircream)

It means, very simply, twice ear. Twice

The bel

loud as what? An obviousquestion.

always a comparison between two things. No matter what system of units of ure you are working with always state a value as a reference before you compare another value to

dynes, webers

doesn't matter, a bel, or ear-

related statement of "twice as loud"

loud to the human

the time, you must

by using bels, volts,

always a

meas-

can

ratio, not an absolute number. Unless a zero, or "no

difference" point

placed somewhere, no

comparison is possible. There are many positive and definite statements

of reference in use today. But before we go over them, we should divide the "bel" into smaller units. "Twice used

al1 the time. How about one tenth of a bel?

Okay, the decibel

ente,

same as the reference".

"nothing". Now, if you double the power,

twice

you double an electrical voltage,

loud" will be a little crude to be

loud? No,

is,

and O means "no differ-

seldom means

only 3dB more sound. If

that

twice as

-1

rquare

newtoiir

newton

rneter

per

100

square

dvner

dyne

per

100

per

cm. l niicrobar

microbar

.O1

microbar

-001

microbar

100'

...

Home in citv, cantinuour background

- - - - - -

noire*(carr,

Homen citv at night

Isoiared recording

Open

icricketr.

rubwavr. rtreet

field, night,

nrect

Auerage

noirer,

converratlun

studio

wind

etc.)

nolre)

Page 6

We should also make a point of mentioning that the maximum number on this chart represents

"peak power" and not average power. The

reason? Consider if even some monetary part of your recording is distorted, it will cording and

wisest to be prepared for the

force a re-re-

highest values and pressure even if they only happen "once in

while". On this point, statistics are not going to be useful, the average sound pressure selves

"statistics" close to the

not the whole story. 'rhe words them-

can be used

an example. Say the word

mic while watching the meters and the peak LED level detector. Then say the word "average". What you are see are two good examples of the problems

likely to

encountered in the "real world" of recording. 'rhe strong peaks in the

"s"

and

"t"

sounds will probably cause the LED's to flash long before the VU meter reads anywhere near "zero" while the vowel sounds that make up the word "average" will cause no such drastic action.

allow peaks to pass undistorted through chain of audio parts, the individua1 gain stages must

al1

have a large reserve capability. If the average speech, but extremely percussive sounds may qui re

results. Woodblocks, castanets,

is X than

much

20dB is usually safe for

90dB of "reserve" to insure good

latin percussion

re-

(guido, afuche) are good examples of this short

term

violence that will show a large difference between "LED flash" and actual meter movement. When you are dealing with this kind of sound,

believe the LED,

is telling you the truth.

Since the reference is assumed to be the lowest possible audible value, positive, and correctly written should sign in front of the number. But omitted. Negative energy value

to be of interest to a scientist try-

dB spl is almost always

have

frequently

dB spl would indicate so low an

ing to record one cricket at 1,000 yds. distance, and

of no significance to the multichannel

recordist. Far more to the point "What is

microbar?" It

is a unit of measure-

the question

ment related to atmospheric pressure and although it down

extremely small, it must be divided

quite a lot before

will indicate the minimum pressure change in air that we consider minimum audible sound. This will give you better idea of the sensitivity of the human ear.

One microbar of pressure change is

slightly less than one millionth of an atmosphere, and you can find it on our chart as 74 dB spl. It is not terribly loud, but As

matter of fact, power of conversational speech level is

also used by the phone company to define

is certainly not hard to hear.

represents the average

feet. This

norma1 earpiece volume on a standard telephone.

Now think about that minimum audible threshold

again:

.O002 microbar.

That's two ten thousandths of one atmosphere

This breakdown of one reference just to amaze you, or even to the quantity of power that moderate sound represent. Rather it is intended to

millionth part of

not given

provide a feel for

levels of

explain the reason we are saddled with a ratiollogarithm measurement system for audio. Adding and subtracting multi-digit numbers might be easy in

this age of pocket calculators, but in the 1920's

its

when the phone company began sound and the human ear,

more easily handled

research into

system of numbers became an absolute necessity.

Conveniente

for the scientist and practical en-

gineer, however, has left us with a system that

requires

great dea1 of complex explanation before you can read and correctly interpret a "spec sheet" for almost any

piece of gear.

Here are the formulae for unit increment, but they are necessary only for designers. And unless you build your own gear, you won't

have to dea1 with them. For power (watts) increase or loss, calculate by the following equation:

LOG,,

For voltage, current or pressure calculations:

LOG,,

v2 v1

(dB)

One whole atmosphere, 14.70 pounds per square inch, equals 1.01325 bars. So one whole

atmos-

phere in microbars comes out to be 1,013,250.

Page 7

Once we have this chart, we can see the differ-

ente

between the way humans perceive sound and the amount of pressure. Unfortunately, the "twice

divisions on

This is how the ear works, and we must adapt our system to it. We

loudspeaker to produce the tivity to sound of the human ear produces strong "energy" illusion that has confused listeners since early times. How powerful are the loudest sounds of music in used such sound the answer so regrettably, consider what would happen one pound of pressure was applied not to your head, but directly to your inner ear. One pound of air pressure variation mount of "power" might do some useful work but not much, make use of it you will away or you will go deaf immediately.

If we reduce our sound power to realistic musical values, we will not be injured, but we will almost nothing (in real power terms) to run the mic with! This low available energy is the reason that high gain amplifiers are required for p hones.

When we take

sound, we do much energy we must the electrical part of our system. that we don't

much pressure" of sound to be heard

"twice

loud". If you plot decibels

very funny curve.

dB = 20

5 10

original sound we begin with. The high sensi-

source of energy to do useful work,

operating a car? For any normally "loud"

force it takes to change air

result is nota simple

the even

graph, the unit increase you need

VOLTAGE,

PRESSURE

iog,,

increase

have no choice if we expect our

is,

it's

microphone and "pick up" the

have some leeway in deciding how

have to truly hear the signal while

CURRENT

20 25 30

RIS~

sound that resembles

real power? Can sound be

regrettably, no! Perhaps not

170dB spl ! This

still only one pound and to

have to stand one mile

have in order to operate

wav

even

1 dB

Unit

If wecan decide

have

micro-

we are processing can wait until the electronic devices have done al1 their routing and switching before we need audible sound, we can lower the power of the signal. What Well, we need to have enough energy so that the signal

not obscured by hiss, hum, buzz or other unpleasant things we don't want, but not so high that

costs a fortune in "juice" or electrical power. This was phone company.

They now system, and even when they started out, ity was not free. They set their electrical power signal reference time, and tronic equipment has gotten better. In 1939 the telephone company, radio broadcasting, and cording industry got together and standardized 1 milliwatt of power standard of related industries. Thus, nal at a 600ohm line impedance will present

voltage of 0.775 volts.

Once again, we owe you an explanation. Why does Why 600 of them and not some other value? What's a volt? Let's look

1. The logic of ZERO on the meter is another hangover from the telephone company tice. nia, the significant information to a telephone company technician in Boston is signal level drop? meter says ZERO company) that there has been no loss in the transmission, and level is one milli-watt of power, but the gain or loss is in the information the meter was posed to display, so the logic of ZERO made good sense, and that's what they put on the

dial. We still use it even though cal ence level described matter what actual power so firmly set in the minds of everyone in the audio world that change.

One ohm of electrical energy. The exact reasons for the choice of 600 ohms nected to the demands of the circuits used

have the world's biggest audio mixing

say ZERO on the meter? What isan ohm?

When you start a phone call in Califor-

for anything else, and the idea of a refer-

it from point to point and we

is a good value for a reference here?

big consideration for the tele-

electric-

low

was practical

has lowered over the years

OdBm, and this is still the

one thing at a time.

If so, how much? When the

indicates (to the phone

al1

well. The reference

"no loss" ZERO, no

being measured

probably never going to

unit of resistance to the passage

standard are con-

OdBm sig-

did the

it's

not logi-

the

elec-

re-

prac-

sup-

. .

Page 8

for long distance transmission and are not simple or easy to explain. Suffice that the worst

possible thing you can do to

to say

piece of electronic equipment is to lower the resistance

is expected to work into (the

load). The lower the number of ohms, the

harder it is to design you think about

"load", the truth

stable circuit. When

just the

opposite of what you might expect! O ohms

"short circuit", no resistance to the pas-

is sage of signal. If this condition occurs before your

signal gets from California to Boston, you won't be "get there",

able to talk- the circuit didn't

"shorted out". Once again, tele-

phone company logic has entered the language

on a permanent basis. Unless the value for

ohms

infinity (no contact, no possible energy flow) you will be better off with a higher value, and many working electronic devices

have input numbers in the millions or billions

of ohms.

3. A

volt is a unit of electrical pressure, and by itself is not enough to describe the electrical power available. To give you an analogy

that may help, you can think of water in a

hose. The pressure is not the amount of water,

and fast the

Increase

ance, or

less

flow will depend upon the size of

hose (impedance or resistance)

well.

the size of the pipe (lower the resist-

and pressure (volts) will drop un-

you make more water (current) available to keep up the demand. This analogy works fairly well for DC current and voltage, but alternating current asks you to imagine the water running in and out of the whatever frequency your "circuit"

at,

and

harder to use a menta1 aid. Water

has never been known to

10,000 cycles per second.

flow out of a pipe

nozzle

working

This reference level for a starting point has been used by radio,

in audio because the

television, and many other groups

telephone company was the

largest buyer for audio equipment. Most of the

companies that

built the gear started out working for the phone company and new audio industrie~,

use

they came along, found

much of the ready-to-hand stuff

economica1 to

they could, even though they were not routing signals from one end of the world to the other.

choice for quality audio. Not so. A 600 ohm, 3-wire

necessity for the telephone company, but the primary reason audio

quality. It is noise, hum and buzz rejec-

transformer-isolated circuit

used has nothing to do with

tion in really long line operation (hundreds and hundreds of

Quality circuitry. In fact, when

miles).

audio does not demand 600 ohm, 3-wire

shielding and isolation are not the major consideration, there are big advantages in using the 2-wire system that go well

beyond cost reduction. It is, herently capable

than 3-wire

of much better performance

transformer-isolated circuits.

Since TASCAIVI M-35 mixer a

signal from a mic to a recorder, we think that

the 2-wire system tionally

accepted standard (IEC) for electronics

wise choice. The interna-

system, in-

designed to route

of this kind uses a voltage reference without specifying the exact load

reference

this:

This is now the preferred reference for

O = l

expected to drive. The

volt

al1

electronic work except for the telephone company and some parts of the radio and ness.

Long distance electronic transmission still

in need of the 600-ohm standard.

television busi-

If your test gear has provision for inserting a 600

load, be cure the load is not used when

ohm working on TASCAM equipment.

Now that we have given a reference for our "0" point, we can print the funny curve again, with numbers on it, and you

can read voltages to go

along with the changes in dB.

log,,+

curve

Must we use this

telephone standard for recording? Its use in audio has been so widespread that many

people tiave assumed that

was the only

Page 9

All electronic parts, including cables and nonpowered devices (mics, passive mixers and such), have impedance, measurable in ohms (symbol

or Z). Impedance presents to the flow of signal, and to understand some things about this value when

the total opposition a part

it's

important

OUTPUTS

plug into

you are making connections in your mixing system. The outputs of circuits rating and so do inputs. What's good? What

values are best? signal flow, and in theory,

It depends on the direction of

INPUTS

have an impedance

looks like this:

generally said that the output imped-

ance

(Z) should be ohms, 10 ohms. The lower, the better, in theory. A circuit with ance will offer a low resistance to the passage of signal, and thus will be able to supply many multiple connections without in performance or a voltage drop in any part

of the total signal pathway. Low impedance values

ing transistors and integrated circuits, but

other considerations are

practice, such as:

1. The practical power supply

can be achieved economically by us-

nitely large. At some point, even if the circuit ergy you will run out of "juice".

Long before this happens, you may burn

out other parts of the circuit. The output

impedance may be close to the cally ideal "ohms" but many parts in the

practical circuit are not. Passing energy through a resistance generates heat and too much current will

right off the circuit card taken to prevent catastrophic failure.

capable of supplying more en-

low as possible. 100 a

low output imped-

still a problem in

not infi-

theoreti-

literally burn parts

if steps are not

loss

Inputs should have very high impedance

high

nurnbers,

million ohms, more, if

A high resistance to the flow of signal at first sounds bad, but you are not going to build the gear. input will work properly and has no for a large amount of signal, you can assume that he means what he says. For you, a high input impedance isan unalloyed virtue.

It means that the circuit will do

minimurn of electrical energy as a beginning. The most "economical" electronic devices in use today have input impedances of many ample, voltrneters of good quality must not

draw signal away from what they are

uring, or they will disturb the proper operation of the circuit. A design engineer needs to

destroying

device to measure with.

millions of ohms, test gear for ex-

see

what is going on in hisdesign without

it,

possible (1 00,000 ohms

can be arranged).

If the designer

so he must have an "efficient"

tells

its

job with

you his

need

meas-

Even if the circuit does not destroy itself, too high a demand for current may ously affect the quality of the audio. Distortion will rise, frequency response will suffer, and you will get poor results.

The classic rneasurement for output impedance

load a circuit until the voltage drops 6dB

is to (to half the load value is. In theory, you now have a load impedance

ance.

If you reduce the load graudally, the dB

reading will return slowly to

How rnuch drop left when an acceptable drop

ter!

original power) and note what the

that is the same

acceptable? What load will be

the output imped-

its

original value.

read on the me-

seri-

When the seven times the output impedance, the

still a little more than 1 dB lower than the original reading.

Most technicians say "1 dB, not bad, that's acceptable". We at TEAC must say wedo not agree. We think that a seven-to-one ratio of input to output (1) is not a high enough ratio, and here's why:

load value (input Z)

approxirnately

needle is

(7)

Page 10

1. The measurement range frequency and does not show true loss

the frequency extremes. What about drop

Hz?

2. All outputs are not measured Most people don't have twenty meters, we do.

Remember, everybody

you record and the circuit demands, in

are simultaneous. All draw power

tice, same time.

Because of the widely misunderstood rule of thumb you the

Even though the true output impedance may be

low, say 100 ohms, for the practical reasons explained previously, we feel that the 7:1 ratio not sufficient. To use this rule of thumb, you must use "output model M-35:

ACCESS

the seven-to-one ratio - we will give

values for outputs in a complete form.

load impedance". For example, in our

SEhID

LINE OUT

higher value. We'll call this value the

usually made

plays together when

1.4k

ohms X 7 = 10k ohms

1.4k ohms X 7 = 10k ohms

mid-

the same time.

prac-

the

level, a loss of headroom, low frequency response,

else

suffer from a bad recording. If one input

10,000 ohms, another of the same 10,000 ohms will give you a total input impedance (load) of 5,000 ohms. To avoid

following when you have two inputs to con-

the

nect to one output.

Take the lowervalue of the two input impedances and divide

7 times the output impedance, you can con-

still

nect both not using the true output impedance, we are ing the adjusted number in group impedance.

When you just dividing the ber of inputs will not be accurate unless they are

al1

the same

(higher than 7 : 1 ratio) by this method, you can

connect without worry.

If you must have exact values, here are the for-

mulae:

in half. If the number you have is

the same time. Remember, we are

have more than two loads (inputs),

lowest impedance by the num-

size.

For more than 2

calculations you can do

output load

But if you still get a safe load

us-

This the 7:1 method. To go one step further, here are the actual minimum ohmic wise. Connect to TOTAL INPUT

LOAD

ACCESS

LINE OUT

Our specifications usually show 10,000 ohms

"Nominal Load Impedance" and you can that we arrived dividing 10,000 by 7. Any number higher than

10,000

Input impedance requires only one number. are'the

MIC IN

I-INE IN ACCESS RECEIVE 220k ohms BUSS IN

If one output puts, the total impedance of the two inputsmust not above, and if it becomes necessary to number of inputs with load specifications, you must check for a drop in

number that will give good results with

values we feel are

IIVIPEDAIVCE

higher than:

SEhID 10k ohms

10k ohms etc.

see

the first column above by

less load.

more straight forward and

Load

load, and here

values for the M-35:

600 ohms 50k ohms

12k ohms

to be

"Y"

connected to two in-

exceed the load impedance, mentioned

increase the

slight exceeding of the

RX=-j 1 1 1

-+-+-+

R1 R2 R3 Rn

For 2 loads or inputs

Finding Impedance Values on Other Brands of

Equipment

When you are reading an output impedance spec-

ification, you will occasionally

statement:

Minimum

Maximum

'rhese two statements are trying to say the same

thing, and can be very confusing. The minimum load impedance says: please don't make the NUMBER of ohms you connect to this output

lower than X ohms. That's the lowest IVUM-

any BER. The second statement changes the logic, but says the exact same thing.

Value of Total Load

load impedance = X ohms

....

see

this kind of

+--

Page 11

Maximum load impedance refers to the idea of the

LOAD instead of the number, and says: please don't make the do you lower for ohms. Maximum ohms, so

When the you already culation. And the number given in ohms does not

have to be multiplied. You can MATCH the value

of your input to this number of ohms ly;

load).

Occasionally, a manufacturer will want to show you that right idea and will give the output impedance and the correct output impedance

will give the recommended lowest

pedance.

times and will be whatever the specific circu it

in question requires.

increase the load? Make the number read carefully.

minimum/maximum statement is made,

can safely assume that the manufacturer has

done the "seven times

but

always, higher ohms will be okay (less

times the output

load this way. They will call the

may be a higher or lower ratio than

LOAD any heavier. How

load means minimum

best" ratio cal-

successful-

not quite the

the true impedance and then

LOAD im-

REFERENCE LEVELS

We should talk about one more reference, a prac-

tical

one.

Anyone who hasever watched

around wh ile recording knows that

is not a fixed value of energy. and can range from "no reading" to "good grief" in less you the numbers for gain, headroom and in the M -35, we must use a steady signal that will not jump around. We use and start it out put, our beginning reference level. All levelsafter

the rnic input will be higher than this, showing that they will come to the

line-out and the reference signal there will be

louder than 94dB spl, or your rnic will produce

more electricity from

-60dB, al1 these numbers will be changed. We

have set this reference for rnic level fairly low. If

you examine the sound power or sound pressure

musical instruments are louder on the average than 94dB spl, and most commercial mics will

produce more electricity than the sound pressure of 94dB, so you should have no

problems getting up of "OVU" on your recorder.

time than

have been amplified, and eventually we

10dB, our "line level" reference.

From this

level

(Spl) chart on page 6 you will see that most

takes to blink. In order to give

a level of -60dB

last

output of the M-35 - the

you can see that if your sound is

sound of 94dB spl than

VU meter bounce

"real sound"

It varies with time

tone of 1000 cycles

the rnic in-

60dB for

noise

If you are going to record very loud sounds you

may produce more electrical power from the rnic than the M-35 you estimate this in advance? Well, the spl chart and the rnic sensitivity are to-one basis. If 94dB spl gives - 60dB (1 mV) out,

104dB spl will give you -50dB out, and so forth.

Use the number, on our chart for sound power together with your rnic sensitivity ratings to find out how much level, then check that against the

maximum input the M-35. or line level, there

it into the You will work

Most rnic manufacturers give the output of their

mics as don't give the loudness of the test sound in

it's

stated

can handle

levels for the various jacks on

If your rnic

nothing wrong with plugging

line level connections on the mixer.

need an adaptor, but after that it will

minus-so-many-dB number, but they

as a pressure reference (usually 10 mi-

an input. How can

tied together on a one-

in fact producing - 10dB

dB,

Page 12

crobars of pressure). This reference can be found

on our sound chart. It

dynes per cm2 or 1 Newton per square meter.

For mics, the reference

the sound the rnic

94dB spl, the electrical output of

given

94dB spl, 10 microbars, "0"

is 1 volt (dB). So, if

-60dB, meaning so many dB

less than the reference 0=1 volt. In practice, you will see up to about

levels of -60dB for low level dynamics,

-40dB

or slightly higher for the better grade of condenser mics available today. TASCAM recorders and mixers work

-10dB referenced to 1 volt (0.3 volt) so, for

of 94dB spl, will

rnic with a reference output of - 60dB

need 50dB of amplification from your M-35 or recorder in order to see "OVU" your meter. Now, if the sound you want to re-

cord

the rnic will be more powerful and you will need

louder than 94dB spl, the output from

less amplification from your IVI-35 to make the needles on your recorder

read "OVU".

OdB) on

level

segments.

1. As laid out for

2. As wired, but knobs and jacks

convenience.

they appear

on the outside.

3. The block diagram, with the controls bered

to correspond to numbers on the first

num-

two drawings.

Even with this "translation system" to help, multiple sources and outputs so when necessary; we will types of drawings to help get the point of

can complicate things,

also include other

sub-

system across when we first encounter a source

"point" that will be used in may

require re-reading if you are not familiar with subsystems, but we think you

early

possible.

specific way. This

best to advise

THE

BLOCK

DIAGRAM AND GAIN

DI AG RAM

Before you begin reading the next section of this manual, flip out the extra fold on page 42. On this page, we

have printed the block diagram. It shows the signal flow through the M-35 and represents in simple form, the actual electron

al1

arrangement of stages from

mic-in to line-out.

the jacks, controls and gain

The diagram on page 43 indicates the gain of

reference signal, the noise level, and the available

reserve gain or headroom

any point in the signal chain. An experienced audio engineer would be able to operate the M -35 successfully

with just these two diagrams and

list

and output specifications.

Any question about function or gain swered by studying the drawings. Will the accessory send signal change in level if the input fader

moved? No, the signal

shown leaving the main line before the input fader. You read both diqgrams from left to right, input to output.

BLOCK

of input

can be an-

When printed in

its

entirety, a block diagram can look formidable, and tracing a signal path easy, so to aid you in your initial understanding,

we'll continue to use our 3 drawing system first shown in the introduction, but in slightly smaller

not

Page 13

INPUT

MODULE

Input Select

Trirn

LINE

All 8 input modules are identica1 and can be in-

terchanged without modification. Mic input Balanced pad circuit contro1 MIC

3 positions are provided: off, or no effect, set

rightwards one step, a loss in signal of rightwards two steps, Before using the first step, reduce the 8 trim

contro1 to minimum or furthest countercIockwise

rotation. Since the combination of trim and pad

is a maximum of 60 this mic-in jack tools are available to convert a 3-wire circuit to 2-wire RCA connector - if the line level signal can be reduced to a max of OdB, (1 V).

XLR

connector

ATT

switch 20dB, set

loss in signal of 40dB.

dB loss,

an emergency "line in" if no

possible to use

XLR

frorn Subrnaster Tape

Input transformer Maximum signal to this internally mounted transformer or MIC ATT switch. At 20dB pad, maximum put is -15dB (17.8mV). At 40dB pad, maximum i'nput

This 3-pin connector, pad circuit, and transformer are the only 3-wire circuits in the M-35.

We ing a better way to do the audio job, and rnic

lines do not run for "miles and miles" in our sys-

tem. Why do we use this more expensive design to begin with if

ity? The low-power signal that the rnic generates must be protected and isolated from other

-35dB (17.8mV) without using the pad

have tal ked a lot about the 2-wire circuit be-

+5dB (1.8V).

offers no improvement in qual-

in'

in-

low-

Page 14

power signals in the real world. Radio power line hum, crackles and switching noise when motors

start up (do you

line?)-al1 these unwanted things-must be kept out of the very high gain amplifiers that are cessary to raise the rnic signal to a working level. So, the balanced or 3-wire, circuit and input-isolation transformer becomes the only cure way to dea1 with the problem:

Here's how it works:

Mic

Any signal will pass to amplifier, no rejection.

Radio Frequency I nterference

Mic

have a refrigerator on your AC

ne-

7~--

Audio signals from rnic have opposite polarity. Buzz, hum, and

Signals with opposite polarity in the primary coi1 will genera1 current in the secondary coil. Signals with common polarity will cancel out in the

mary coi1 and will not pass to the secondary coil. No signal in the secondary in the amplifier.

RFI

have common polarity.

rv Secondarv

/=%;j'lL-i

RF cancels in transformer

coi1 means no signal

pri-

Right here we comprehension. The connection and is

drawn plainly on the block diagram, but what

does

mean in functional terms? Why

PUT switch wired to this extra LINE IN when there

another LINE-IN on the module? The

answer

tem in use, and to explain, we'll have to show the system in

not reviewed the first path to the recorder

We must assume that a recorder has only one set of playback outputs. We will

basic jobs to do that

Three tasks, one output. How do you plug in? This

module, not the input module, and the

tions are laid out on the back like this, part of our standard "working patch" for 8-track

ing.

lies in the requirements of an 8-track sys-

Simple playback to judge performance, requir-

ing no corrective EQ. In short, what did you record

Simple playback into a cueing system so partially

function should somehow combine the signals

musicians may hear when overdubbing.

Final remix, when the full contro1 capability of the system used to "fine

completed tapes can be finished. This

simple playback with new rnic signals, so

special input RCA Jack is on the master

have our first major problem in

its circuit

the IN-

its

entirely, even though we have

all.

have at least three

require the playback signal:

(EQ effects mixing, etc.) can be

tune" the finished tape.

sections

record-

Input Select Switch

This switch has 3 positions. Left selects the IMIC-

IN XLR. Right selects the LINE IN RCA jack on the back of the module, and center selects one of the TAPE IN jacks on the buss master mod-

ules. Since each input module will receive only one TAPE IN signal, we'll show which signal goes to which module.

provide a chart to

Page 15

The numbers on the input module now relate to

the jacks on the submaster. Track one from tape

playback will now be available on three separate

systems. If only the "line input" on the input

module

used, the signal will only be available

for "re-mix" and

al1 module settings for "mic" will have to be disturbed - every time you playback. By using the TAPE-IN jack, resetting

is avoided. Another drawing may rnake the wiring more understandable.

for contro1 roorn

M-&\

Track 8 playback

To keep the routing clear, we show only the last submaster module that handles track 8 and track

The other groups are similar, routing signal to

EXPANDER INPUT

EFFECTS RCV

their respective input module numbers

shown

in our first drawing (the one with the 8-track).

TAPE

11-41

CUE OUT

EFFECTS SENO

1x11

TAPE IN

15-81

AUX IN

CONTROL

STUDIO FEED

STUDIO FEEO IREAR1

STUDIO FEEO

TALK BACK

RDOM

Page 16

Now for the three requirements of tape playback:

Simple record check To do this, the tape playback signal tuted for the monitor output signal on the submaster monitor select, and the monitor

mix

now derived from tape playback on each

section so switched. Any or

substi-

al1 8 may be

selected individually and the

master room loudspeakers.

will then set a level for the control

control room

Page 17

-Q

T-.,

Cue System Tape playback plus

LINE

1.81

RCY

EFFECTS

EFFECTS RCV

EFFECTS RCV 4

-0

mic cueing for overdubs.

,Lo~nan

"i,

.-v:...

,llllllll~'

l l

l.l l l

*oirin.""-o

81155 IN

(.41

OUT

LUNE

(x41

nux OUT

1x4)

TAPE IN

1141

CUE

OUT

1x1)

EFFECTS SENO

1111

TAPE IN

15-81

From

Tape 4 Tracks

This cue system combines the tape playback con- "hear" trols

(x8) on the submaster modules with the input cue controls (x8) on the input modules to form a mono sum of al1

possible signals that

buss allows you to set levels; but caution is advised. The headphones volume may not directly to your

it,

and a meter shared with the effects

contro1 room volume. You have might be needed for a musicians cue. Since the a master for loudspeakers, but monitor system for the

contro1 room can be set

to audition this signal "mix" you

will be able to

this mix in the headphones. The master pot.

relate

does not affect cue mix has no

Page 18

Tape-in for Rough Remix

MIC IN

1x01

EFFECTS RCV

EXPANDER INPUT

AUX OUT

1x41

TAPE l N

11-41

CUE OUT

11 Il

EFFECTS SEND

111 I

TAPE IN

15-81

When the INPUT select switches on the modules are set to the center position, the

submaster

TAPE IN jacks are internally connected to the

input modules. Selecting this remix position on

the input module will not disable the

norma1 operation of the monitor. Signal will go to both circuits

the same time, allowing separate use of the monitor outputs as extra mixes. True stereo echo is an obvious first choice, and the mixdown AUX IN position on the module. one module

machine can be monitored using the

contro1 room monitor

Since the remix position can be selected

time, a single track may be

equalized and monitored without disturbing

mix

track

MIC

IN settings on the whole mix. A decision can be made quickly on the artistic success or failure of an

individua1 part without the need to place the entire console in remix mode just to see the effect of corrective equalization on single track. Since the TAPE IN jacks on the buss master moduels actually feeds 3 separate

mixing positions

load to anything connected to

on the module. TAPE

will present a more severe

than "Line in"

IN'S have an input load impedance of 20k ohms and LINE IN'S (on the input module)

have an input impedance of 50k

ohms.

Page 19

Line In Jack

An RCA jack on the rear of each input module. The maximum signal you can apply here +15dB. The MIC ATT switch does not affect

this input. The input impedance 50k ohms.

Trim

control will alter the gain of the first ampli-

This fier in the console. It will affect the level of any

signal, M IC, LI NE or TAPE. With this pot rotated

fully clockwise (rightward), the maximum gain

of the first the maximum input

1 l dB (282mV). When the pot is in

amplifier is 26dB.

signal before overload is

In this position,

its

minimum setting (fully counterclockwiseor leftward) the gain

reduced to 5dB and the maximum signal that can be handled without overload will be +10dB (3.2 V). Remember, these overload figures refer to the input of the amplifier, not

the input

pads

plug or connector. Losses occur, and

can be inserted before this point. The maximum signal that can be applied to the LINE IN jack is +8dB (2.5 V) with the TRIM rotated

fully leftwards, and +30dB (31.6 V) with the TRIM rotated

the gain of an amplifier by adjusting the

trol

amount of output

input reverse

control "pot" or input. Because of this

control aspect, we consider it unwise to adjust the TRIM Obviously, you must adjust when signal

but when serious recording

fully rightwards. Trim pots con-

signal returned to a secondary

while signal

being recorded.

present,

in progress the possible negative side effects on amplifier stability and distortion indicate that you should "mix" with the straight

master faders

line input, submaster, and

only, and adjust "trim" during re-

hearsal.

Cue Pot

At this point in our input module, we derive signal

for a or headphones mix. This function

is best served by

constant after being set, so

mix of signals that will remain

drawn off, before the input fader. To raise the level, rotate rightwards or

clockwise.

This pre-fader source insures that your mixing decisions the studio. The

will not interfere with the rehearsal in

only thing that

more annoying

to a player wearing a headphones than a sudden change in tone

instrument tion is in large part a response to what and if the

losing track of the sound of his

entirely. Remember, al1 music execu-

heard,

main source of sound is provided by this headphones "mix", and you turn it off in the course of some other

control room action, you will deprive the player of the creative guide to what

going on. Your session may stop cold right then. 'rhe cue system routing has been drawn on page 18 and shows the 16 sources of signal and the inputs and outputs on the back panel.

Overload LED

When signals high enough to make the ACCESS SEND jack output an input

module, this LED will light up. The

exceed

TRIM, or the MIC ATT pad

5dB are applied to

should be adjusted

until the LED remains out when signal ispresent.

When recording

extremely percussive transient material, it may require full negative trim and pad (MIC ATT) to prevent this LED from

flicker-

ing on strong peaks. Changing to a less-sensitive

may help.

rnic

Access Send - Rcv Jacks

The high gain provided by the rnic preamplifier

allows useful position. The level at the

-10dB (0.3V) and the output load impedance

us to place a "patch-point" in this more

SEND

jacks

10k ohms. A limiter connected to this point in the M-35 circuit compression that the

equalizer (next stage) is adjusted or the input

fader

moved (the stage after the E0 amps).

This pair of jacks is not

device

bridged from SEND to RCV, jumpers

must be in

can now be set to a range of will not be altered when either

"normalled" so, when no

place for signal to flow to the E0

amps and on through the console. However, since

al1

the mixing controls lie after the "RCV" jack,

possible to use "ACCESS RCV" as an input,

and by-pass the first gain stage. The only

func-

tions that will be lost are the trim and overload

indicators. The signal quality will improve slightly

but

will not be possible to switch to "MIC

IIV", "LINE IN" or "TAPE" without repatching.

This unorthodox patch

suggested for final re-

mix when al1 recording has been completed, and

time for patching

level in will be +15dB. Input impedance

available. Maximum

220 k ohms.

Page 20

PARAMETRIC EOUALIZER SECTION

Before we begin, the label itself will requiresome

explanation. What

what

A logical quest ion, because the term does

parametric and, equal to

not describe what you do with the controls. In multitrack audio, tone controls are almost

always used to "make different" and the concept of "make the

get this The telephone companyuses

same" doesn't quite fit. How did we

label on our tone control?

it.

In the earlydays,

the system worked well in the lab, and in short

runs of 100 yards or so, but

. . .

. .

When two "phones" were 10 miles apart the line between them did not transmit al1 of the sound representing signal in the

same way. Some parts of the frequency spectrum did not pass down the

line at all, some parts were different in level

or displaced in "time". What came out of the ear-

was definitely not what had "gone in" 10

piece miles away and understanding proved to be difficult. What now?

conversation

'rhe Phone company had to learn how to make the output "sound like" the input.

If "output equals input"

the concept, an "equal-

izer" is a logical name for the device used to fix your problem. Just as in many other concepts in audio, the telephone company language has set the terms we use today.

The term "parametric" refers to the

adjustable frequency point. The "parameters" or "rules" are not fixed at any given number, but are ously

variable. Both aspects of the circuit, fre-

continu-

quency center point as well as gain or loss are continuously are

limits.

The

Model 35 offers a two control, four range

adjustable without "steps" but there

parametric equalizer. The lower group of controls offer

+10dB of boostlcut control at any frequency between 60Hz and 1.6kHz in two ranges, selected by the switch below the concentric

controls. Set leftwards, the switch selects the range from 60 to fully leftwards or counterclockwise then sets

center frequency of 60Hz. As the outer knob

300Hz. The outer knob when see

rotated rightwards (or clockwise), the center frequency right (or clockwise), the center frequency

raised in stepless fashion. When fully

300Hz. The inner knobT the boostlcut control. Set fully leftwards, the cut rightwards, the boost

is -10dB. Set fully

10dB.

When the lower switch the action

the same, but the range changes.

Outside Control, rotate right to raise center frequency.

Inner Control rotate leftwards to cut rotate rightwards

toWboost"

set fully rightwards,

Page 21

The upper group of controls offer

or cut

any frequency between 1.6kHz and

OdB of boost

As the outer knob

rotated rightwards or clock-

wise, the center frequency

raised in stepless

15kHz in two ranges, selected by the switch be- fashion. When fully right, or clockwise,

low the concentric controls. Set leftwards, the switch selects the range from 1.6 to 5kHz. The outer

knob when set fully leftwards or counter-

clockwise then sets a center frequency of l .6kHz.(p

-P-

center frequency The inner knob

leftwards, the cut

wards, the boost

5 kHz.

the boostlcut control. Set ful-

is - 10dB. Set fully right-

is + 10dB.

When the upper switch

set fully rightwards the

range once again, is shifted upwards.

oci--

IL-

The center position on both upper and lower frequency select switches

"off".

The great advantage of

"parametric" or con-

tinuously "tunable" equalizer over the more con-

ventional "set" types

that you can tune your frequency center point to the precise area you need, and then cut or boost will have the rnaxirnum desired effect on your art. You get the result you want with rnuch less rotation of they

boostlcut

control, and put less "strain" on your electronics. No matter how many "frequencies" there are on that anyone

"set" type equalizer,

will be "just right" and many more

unlikely

ranges are needed to do the job. In the long run

"parametric" type requires fewer parts to do

the job so

costs less, and perforrns better than

Page 22

"graphic equalizers" which rnay leave rnany sections unused on a given input, or "set frequency select" types which never seern to have the right "nurnber"

electronics using the tone controls on rnic to get as the rnic. Even a rnake a big difference in the sound quality. Listen

to the sound frorn the

your head where the rnic is, and listen carefully.

What do you really hear? Is

Doing this check rnay

Too rnuch bass? Not enough? Well, perhaps there

better location for the rnic in order to get the

balance you need. When you have gone as far

you can in this fashion, the tone controls will get

you the rest of the way.

However, the "ear test" rnay not be wise, if the

volume of sound

head near to any part of a drum set. Even if

moderate force

rnic

to cause perrnanent darnage to your ears.

available. "Less"

alwaysthe safest route, so before

close to the sound you want by moving

srnall change in rnic location can

a working concept

signals,

actual rnic position. Place

what you want?

help solve rnany problerns.

better

very high. Don't put your

only

used to play drurns, at close

distance, the sound power rnay be enough

For a steady tone frorn an organ or a violin, this

rnight be just enough to avoid

distortion, but with any percussive peaks frorn things guitar or drurns.

Even experienced engineers forget that "cutting" the effect to "boosting" the highs, and is much easier on the

and sults rant trying. Cut bass, raise the overall gain, and

see if it sounds better than

highs.

electronics (cutting leaves more headroom

consequently causes less distortion). The re-

are not identica1 but close enough to war-

definitely not enough to cope

clipping, or serious

like piano,

have a tendency to

lows will have a sirnilar

sirnply boosting the

If you have the timeand a co-operative rnusician, experirnent with different combinations of rnic placement and tone control settings. Although can be very tiring for sorneone to play a part over and over again best way to get the knowledge of rnic technique

tonal balance you need to rnake good rnixes.

and In fact, experience

work on your specific problern, i.e., your guitar, your

voice, your rnusic. All the inforrnation we

can give you in the rnanual will only be a starting

point. How far you get

On the

that the tone

(IIOdB) and a very largeexcessgain capability or "headroom"

the assumption that the tone the serve in the circuit is necessary to rnaintain a 20 dB value of "headroom" when the tone controls are set for maxirnurn effect. Without this extra

rnargin, you the input fader when you used the extrerne boost or cut settings of the tone

block diagram and gain chart you can see

"flat" or "no boost or cut" position. The re-

while you "go to school", it's the

the only teacher that will

will be up to you.

control stage has a moderate gain

(25dB). This gain chart isrnade with

controls are set to

would have to lower the setting of

controls.

Add 25dB and you boost kHz, your margin of safety

up - if you start with a reserve of only

0dB (the rnaximurn) at 10

reduced to 15dB.

Page 23

npu

Fader

Controls the signal level from

Faders, cause loss in order to stages in an electronic open" they

also called pots or attenuators always

control signal level. Gain

device always run "wide

whatever gain they are set for, unless

have provisions for "TR IM" or actual gain

al1 prior stages.

adjustment. In the M-35 only one of the many amplifiers employed first gain stage or advance any straight are just reducing the loss signal flows to the next stage only if the fader "wide open", or up

actually has "Trim", the

mic preamplifire. When you

line fader on the M-35 you

causes. 'the entire

al1

the way.

Effects Send Pot

This rotary control

the preferred location to

use when a secondary "mix" must reflect the

prior mix decisions of level and equalization.

"Echo Send"

good example of such use and this post-fader, post-equalizer signal will then also "fade out" as you "fade out" the regular signal with the input fader. Eight signals, one from each

module can be combined, and metered and will appear on the backpanel output jack marked "EFFECTS SEND". On the M-35, this mix cannot be monitored separate1 y until the effects trol on

its

returned

aftft

processing by

device. This send has no master con-

output.

EFFECTS

RCV

EXPANOER

INPUT

"buss in" or piggyback,

provided toallowadding more such "effects" signal from an expender or another mixer. "Effects Return" lines will be

but

no master,

and no separate monitor.

drawn later when we get to the submaster modules.

Page 24

Direct Out Switch When depressed,

rect out jack on the back of the input rnodule. Push to lock, push again to release.

Direct Out Jack Provides an unmixed single signal output of

ever has been assigned to the module. This direct output as:

can be used for a variety of purpose, such

A subsidiary mix can be made by using an ac-

cessory mixer fed by this output.

One-rnic, one-track recording happens frequently, and using DI RECT OUT will pass unneeded ing "Direct" to the recorder will result in a

cleaner signal.

sumrning networks and amplifiers. Go-

allows signal to pass to the di-

what-

track monitor

Channel Assign and Pan Pot On the M-35 rnonitoring will be possible by switching the appropriate monitor section to

"TAPE" and listening to the recorder instead of a buss rnaster. For metering, either the recorder or an accessory meter bridge (MB-20)

Since the amplifier that feeds this jack also feeds

the buss-assign network and the post fader effects system

fully. The 10k ohrns. The load of the pre-wired circuits restrict the connection of this output to a single circuit at a on connecting here

values for input irnpedance

it is wise to calculate the total load care-

output load impedance of this jack

time, unless the equipment you plan

known to have a very high

(100

can be used.

ohms or more).

Stereo monitor

no monitor yet, so monitor playback

out electronics with

switchable buss/tape monitor

M-35

Page 25

Solo System

This rnomentary pushbutton will divert input

rnodule signal directly to the monitor section, replacing the subrnaster monitor rnix with a single signal. Although these switches do not latch,

more than one may bedepressed sirnultaneously,

providing a mix of those buttons "held". The

nal "rnix" in the monitor This location as rnodule will

source for signal on the input

allow auditioning

"center feed rnono".

EQ,

but the input

sig-

fader rnust be advanced for the signal to flow.

Since no "return type solo" is provided on the

submaster rnodules, effects-returns will be rnuted

as well as monitor when any solo

held down. Since this entire systern affects only the monitor output (not the direct out or the master

bussouts or any other minor as well as rnajor output), al1 recording will continue unaffected while this solo system

in use.

The channel-assign switches and the pan control

together make up the last section of the input strip. At this point you

has appeared at the direct-out jack,

been set with the input fader and you the necessary changes in

What rnaster

"line out" do you want

have selected a signal,

its

level has

have made

its

tonal quality.

to go to?

Line one, line two, line three, line four - any or

al1 may be selected by depressing the appropriate

buttons on the channel-assign strip. Push to lock, push again to release.

Depressing more than one button will engage the "Pan" control. This single knob works two faders

that are wired "back to back". As you rotate the

knob, one fader ed down. When the control fader

still

turned up as the other

"dead center" each

turn-

reducing the signal slightly so that the signal transition through "center" does not becorne louder as you "PAIV" through

it.

When both speakers in a stereo pair are producing sound, you don't tain a constant volume. If only one button

need as rnuch power to main-

depressed, the pan control has no effect on the signal. When any two buttons are depressed, the lower number control

wise. The higher

"Panned" to full on when the

turned as far as

"Panned" tofull on clockwise.

will go counterclock-

The "PAIV" logic for

or 4 button arrays

easiest to explain with some drawings. If shaded buttons are assurned to be down, the logic is:

Typical examples

multichannel panning

Summing Amplifier

Leaving the Pan/channel assign, the signal ed through a "surnrning drop in level before the surnrning

arnplifier. This loss

resister"

and suffers a big

allowed to pass down

pass-

necessary to prevent the signal frorn one input going back into another instead of going down the master fader. You

can think of the surnrning re-

line to the

sistor as the "traffic cop" that turns the line into the "one way street" you

Buss In

Jack

need here.

The prirnary purpose of this final input on the block diagrarn

to 'StackMor run a pair of rnixers with one overall rnaster control. The input irnpedance

and signal point are identica1 to the accessory receive jack. Any electronic device that has a cornpatible output irnpedance rnay be connected here and

its

contribution to your rnix will

then be controlled by the subrnaster fader on the

M-35.

Page 26

SUBMASTER MODULE

Effects receive to "buss" function actually comes first only if the latching pass switch by the rule of "wiring first"

we'll pick up the sys-

tem now, and mention that we will see

down, but

again

in the monitor section.

Effects Rcv Jack An RCA connector on the back panel of the

submaster module intended as line level input to either the summing amp

(Buss) or the monitor section signal route, depending on the position of the

mon/pgm switch.

Effects Rcv Pot

This rotary control adjusts the signal received from the RCA effects-receive jack.

Mon/Pgm Push Switch When depressed, signal from the effects RCA Jack

assigned to the buss summing amplifier.

Master Fader

This four-ganged

Section) pot provides final level control of al1 four output sections of the mixer. This signal control operates at once. Any signal added to a buss from the ous jacks on the M-35 will be affected by the ting of this control, if your mixed signal

al1 four faders

vari-

set-

taken

from the last output pair on the block diagram.

Meter Drives and Meters Two lines are shown on the block diagram here:

one to the monitor circuits, one to the meter

circuits. We'll go "up" on the block first, and dea1 with the visual references, the meters and peak

LED. These two circuits

ly,

and will respond as set. .Original setting for

the LED

ampl

can be adjusted internal-

OdB above 1 volts. Original

setting for the meter is OVU = -10dB. Pad Switch

On the back panel of each submaster module, this switch when set rightwards (when you are facing the rear panel) will lower the

(0.3V),

output to -10dB in order to match the

inputs of most TASCAM recorders. When

-2.2dB

set

left-

wards, the output will be higher. There is no

need to adjust the meters because they follow the

signal at "high" be

visually correct for either setting.

al1 the time, so the "zero" will

When raised, signal from the effects RCA jack assigned to the monitor system only. You can hear

it,

but

won't "record".

Let's leave the monitor system and

its

multiple

functions for a while and return to finish our

"main line" out. Su bmaster Fader

This fader controls the overall level of

signals from the input modules and the effects receive section, when effects are selected.

Line Out - Aux Out

One last gain stage appears after the master fader and just before this double output jack. A amount of gain

necessary to make up the loses

small

caused by wiring up the master fader, and to give

a solid source of signal with

low output impedance to whatever you are

mixing to. The on the setting of the

final reference level

high/low switch on the back

stable and relative-

dependent

of the submaster modules.

Either -2.2dB (0.78V) High

Or -10dB (0.3V) Low

Since the two output jacks are connected to the

same gain stage, any device connected to one pin

will affect the output capability of the other pin.

To determine the true value of loading on the

mixers

final stage, the input independence values

of both devices must be considered even when only one of them

being used. For this reason

Page 27

we suggest that you unplug anything connected to the make your most pedance

final stage that you are not using when you

critica1 mixes. The output im-

of this stage

100

ohms.

It's

always a good idea to use

of electronic stages a circuit for

you can. If you don't need

its

control or function, bypass

and your sound will improve.

small an amount

At this point in the circuit we

Buss Master Mix.

All functions of the input mod-

have a complete

ule will affect the signal here, al1 majorand minor

patch points are behind us, and corder

concerned, the signal

we are done. The only problem remaining is:

far as the re-

ready to record

how do we hear what we are doing? This signal must go to our monitor circuits.

Monitor Section Function The block diagram shows the controls that in-

fluente

the monitor signal as a "one module" layout, but al1 four submaster modules have slightly different labels to account for the TAPE IN jacks

and their relationship to the input modules. To

make functions more understandable,

we'll show the ent ire top panel as it appears on "the outside". Several aspects of

control require the entire sec-

tion, and the top panel will help.

Buss as Source (Diagram)

There are two switches that seem to do the

same job, feeding signals to the monitor system. This apparent doubling of function

provided for severa1 reasons. Even though the M-35 has only four buss master modules,

has an 8-track monitor system. Setting the monitor select switch to the left selects "buss master output" as a signal.

Resetting to the right-most position will now

select "Tape" positions to monitor the playback of Because of this 8-track monitor requirement,

a monitor, and we need eight

al1 8 tracks.

al1 monitor controls are doubled and there are two apparently identical sets of controls. When used

"Buss Master" monitor, they become redundant, but the two sections are not identical in "Tape" mode. Monitor section "A"

connected

only to TAPE IN A, and monitor section "B"

toTAPE IN B.

only

Page 28

Tape as Source

If our basic 8 track setup on Page

will get

monitor or Buss Master Module (one for each). Upper tape select will be track

will be track

buss master

Monitor Select Switches. However, this switch does not the Tape circuits immediately above, it only works on the rotary fader marked "Mon Gain".

different track on each section of the

Both monitor section will see

when Buss Out

control the logic of signal selection for

used, you

lower tape select

selected by their

Monitor This dual concentric pot (one inside the other) controls both the level and the monitor pan.

inner section pan. or vidually

Monitor Pan The Monitor Pan affects only the monitor mix.

It will not alter the level or pan position on the

Buss Master output when input panning between two busses; but, if both selected busses are monitor-panned to the reo monitor mix, turning the input pan will produce no audible result. Input panning will, in fact, affect what you record, but you won't

unless the "Monitor Pan" on the two busses are

set one to each side. This fact

of trouble. Work through this part of the block diagram carefully, it take sometime to understand thoroughly.

GainIPan

the gain, the outer section

sections are provided for 8-track playback

buss output monitor. Each section

switchable to Buss or Tape.

same side in your ste-

have any indication of what you are doing

can give you a lot

very complex, and can

The

the

indi-

done

control

Page 29

EFFECTS RCV

This group of controls enters the monitor the same point switch, but to

its

center position, the Effects return signal

will be

al1

Group

the BussITape monitor select

slightly before

it.

If the switch

set

that remains in the monitor, and you will be able to hear "effects only". This signal enters the system prior to "pan" so effects signal

will appear in stereo on the monitor section. The button group input Jack the right switch

can be made to receive signal from

by setting a back panel switch to

(as

you face the rear of the M-35) the

on the Master Module in line with the

affected by the pan pot

entire four pot and

level HiILow switches, set leftwards, each effects receive section

its

own effects in Jack. Set rightwards, module feeds

al1 four sections internally with the same

routed to

its

own module via

effects receive Jack

signal.

NORMAL

BUSS

Page 30

MASTER/MONITOR MODULE

Master Fader

This four-section slide pot appears here physically but the outputs vidually

on the submaster modules.

Solo Level

This rotary pot controls the level of the solo system when a Solo signal replaces the regular

monitor signal. Check this before you depress "Solo" or the setting may be to high or low.

Control Room Group

This rotary pot and switch controls gain, and selects signal for the control room outputs on

the back panel. The switch has three sources.

1. Set leftwards Selects the monitor eight-group gain and pan as source.

actually controls appear indi-

Set "Center"

2. Set "Center"

The signal source becomes the Cue 16 mixer.

3. Set rightwards the monitor signal source

comes the signal present at thelRUX IN" Jacks on the rear of the master module they appear

line" with the buss-outlaux-out jacks.

X-1

be-

Outputs for the control room group signal are marked "CONTROL ROOM". Output level

-2.2dB (0.8V).

Max output before clipping

+18dB (7.9V).

Auxiliary Line I n Jacks

A stereo pair provided to allow the monitoring

of a 2-track recorder or other subsidiary without

the necessity of disrupting assignments or patches

elsewhere on the M-35. These Jacks

also feed the

adjoining Studio Monitor Pot.

"Studio" Control Group

This group is identical to the control room group

its

sources of signal and logic.

duplicate identical in

al1 ways except one. Solo,

provides a

when depressed, will not appear on this output,

will still carry the "mix" you have selected.

Output level is

-2.2dB (0.78V)

Max output before clipping is 27dB (22.4V)

Cue Out Jack

Shown earlier, this Jack carries the 16 X 1 (mono) output of the Cue system.

Effects Send Jack

Also discussed, this Jack carries the 8 X 1 (Mono) output of the effects-send Pots on the input modules.

Page 31

Cue in Expander Jack

This jack, allows you to add signals to the 16 cue mix. Level control will be necessary from your accessory.

Effects in Expander Jack This jack allows you to add signals to the

effects output. Again, control on this input, level control "outboard" will be required.

since there

no separate

TALKBACK MODULE CONTROLS

Front Panel Headphone Jack

This standard ring-sleeve-tip (3) wire connector

for stereo headphones

This jack is driven by

IVlax power into 8 ohms

What signal appears here is controlled by..

Headphone Select Switch Selects either the control room group (set left)

or the studio group (set right).

can be connected here.

headphone amp.

100mW.

. . .

AND RELATED OUTPUTS

Talkback Mic

A built-in condenser microphone will allow you to "talk" to 3-circuits on the M-35.

The Cue Buss A level control switch will enable the circuit.

The Studio Output Group The lowest pot sets the switch enables the circuit.

"Slate" This push switch is in the center and volume control will apply talkback signal to four output masters simultaneously, allowing you to

verbally identify a tape (what take, what tune,

etc.) Slate Tone

If this switch is set rightwards, a 60 be added to the slate push switch and pot. When re-winding as

medium pitch "chirps". If you count them, you will have a guide having to slow down and "play" the tape.

Talkback This 2-wire jack

talkback

amp and single speaker to your studio, and use

the studio group for some other purpose.

rnic signal if you wish to run a separate

provided, and the top push

rnic level, the lowest push

its

al1

tone will

high speed, slate tones can be heard

to where you are without

provided to give access to the

Headphone Level

For control of headphone volume.

Solo Expander Coupling Jack This three-wire ring-sleeve-tip circuit couples the

solo function between the M-35 and the M-35

Expander Frame. solos together. Be use

wired this way.

The two remaining controls on the M-35 are on the meter panel.

Power Switch

Enables AC, tion

30 watts.

NOTE: See page

note for U.

Meter

Select Switch

This extra meter

output level of either the

mix. Set CUE for

fects send.

It will not couple two M-35

sure the connecting cable you

"Solo"

cable

120V,

GCIHz,

can be switched to show the

cue mix, set EFFECTS for ef-

IVlax. power consump-

for voltage conversion and

Customers.

cue mix or the effects

Page 32

STANDARD PATCHES AND SET-UP ADVICE

The standard patching setups described here are

not rigid commands. Rather, they are provided

with the hope that they will stimulate your agination when you have mixing needs that cannot be solved with the standard setup. Line level

line level, whatever the source, and many line-

level inputs to the M -35 offer a route to a mix

that will be used for

one that on the back are there to be used. Patching a crime and may be used to improve the quality of your signal by bypassing or by making additional orthodox ways.

Most of connections when they set up

and just on the top of the mixer takes some become familier with, but multichannel record-

ing has many mixing patch affraid to re-plug. There is nothing wrong with the concept. of each mode of operation and re-patch the M-35 to suit, you

For this reason, we suggest that cess to the back panel of the mixer. Don't set up the system in such mess". Leave nectors. You will need al1 the options you can get.

RECOMMERIDED 8-TRACK SETUP

The basic function discussed in this

sumes have recorded many times before final mixes are made. ing

a11

only 4 buss master modules

has limitation. Here we show each buss master connected to more than one track. Tracks

are on the 4 Output, connected to tracks 4 and 8. When

you are ready to mix to stereo, you change your patch to feed the 2-track. Designed for quick playbacks, the Monitor system nates the need to distrupt the Input IModule settings you are working with. Since "LINE IN" on the Input Module is not used for your recorder in this patch, these Jacks are

able for any other unit or units you may have.

labelled on the top panel. The Jacks

people tend to look for a "permanent" set

true that the logic of control function

will severely restrict flexibility. Don't be

If you can examine the system needs can get better results.

yourself room to get al1 al1 the con-

that you will need to playback what you Since it

8 tracks

same buss,

function other than the

unneeded controls,

control possible in un-

mixing system

requi rements. A permanent

you plan on ac-

way that you "hide al1 that

manual as-

unlikely that you will be record-

one time, the fact that the M-35

not a serious

and so forth up to Buss

will have to

playback of

im-

not

time to

and 5

elimi-

avail-

Moving to "LI NE IN" will, of course, force you to re-set the input controls if you a Microphone as an Input. Only one Echo system is shown. cording isdone "dry" or without Echo, one chamber should be sufficient.

al1 patching and connecting of 2-wire single

In ended, circuits two basic

bering:

Keep your cable runs SHORT! possible. Installing gineer will require not recommended. To the left or right side

will allow much shorter runs, and wisest of al1

to use our PB-64 mounted on top of the

Meter Bridge

the shortest

prove your sound. Incidentally, short runs cost

less,

also a benefit. TEAC low-loss cable available and superior insulation has been designed with sys-

tems like this in mind.

cost. The use of 3-conductor professional cable such

though it right idea for 2-wire systems. to make our 500 ft. bulk

8218. Solid is

what you need. Foam-filled 2-conductor

not recommended, as the center conductor

will cut through most foam with time, the ca-

pacitance will go up, and eventually the cable

will short circuit. Don't use it.

2. Multiple output connections ance matching calculations. Make sure you are

not asking too much of your output stages.

Permanently connecting singleoutput may produce poorquality. If you are not using a patch, may cost you quality, unless you are sure that

multiple connection iswell within safe limits. Use the section on impedance matching in this manual, abide by the limitations you will get better Using a Y-cable to "sum" or join two outputs to one connector Since there is no "one way" sign on a wire, signal from one side of the "Y" will flow back into the mixer as Summing, or adding two signals together, re-

quires that they be isolated, and simple joining of the hot leads

itself. This location will permit

lengths of cable run, and will im-

its

Belden 8451 should be avoided. Even

of excellent quality, it is not the

up your own cables we would suggest

core insulator, low capacity wire

weII as on to the next device.

will not work properly.

rules are worth remem-

patchbay behind the en-

least 20-foot runs and is

low capacitance per foot and

rolls or cable such

unplug it! Convenience

results.

will NOT BE POSSIBLE.

have been using

Since most re-

short as

well worth

If you are going

require imped-

severa1 cables to

its

Belden

covers, and

extra

Page 33

Recommended 8-Track Setup

to monitor Amp and Speakers

cue

(headset arnp)

To Echo Effects return

ects recieve "mono" record

The

M-35

has two basic subsystems for cue and effects but they are both "mono". If you need either another accessory system of a stereo version of pre- or post-fader signals, we offer an accessory line level device called the Model

Signal continues, via foldback or Bridgeing Output.

Par

8765432

track from 8 track

Playback

It will "rnix" 8 signals to stereo without permanently "using up" the possibility of a second connection of the signal source,

M-l

front panel

works this way

Signal in

All 8 inputs use this "pass through" or bridging

input method, so you

way to another

can "pass through" on your

necessary connection, and get two mixes or more for one signal source group of

two groups of

or "what have you". In our

illustration we show first,

A "pass through" from an 8 track recorder, this "mix"

effects-send without

thing,

can be used as a stereo cue, or an

Since

"pre" every-

will stay on, and not be affected by

any console control.

Page 34

In this second model, one patch point uses

"pass through" again, and signal-by-signal

patched through the accessory send-rcv point put load on each input module. You now

have a pre- accessory send

cess-send to one, then pass through the second, and then back to access-rcv. Since each in-

k ohms, the actual load on the

is 1 l

k and

safe. We don't refader, pre-equalizer stereo cue mix in addition commend more than two here. At this point to the "mono" that

built-in. you get anything assigned to the module;

Need two? Cascade a pair this way, from ac- "Tape tracks", "Line ins" and "Mic ins"as well.

If you need an effects-send that contains the "assigned" by using the direct-out button on results of input faderadjustment and equalization, use the direct-out source shown in

#3.

ple

Now your "mix" can be "muted" or

exam-

the module and will also follow fader action. Two units may be cascaded as in the previous example if necessary.

Recommended Locations for Model

in tape return

Taoe

in"

Page 35

8-Track

For our

radica1 re-routing that can be used when your track tape has been finished and you want to squeeze that last drop of performance out of your M-35 in move the

tion on the submaster "tape ins" to accessory receive.

preamp, the trim pot and the overload "light",

but you don't will accept

Mixdown

last

patching example, we'll expalin

final mixdown to stereo. First, we

track inputs from their standard loca-

Pulling the jumpers will disable the mic

need the mics and the circuits here

+10dB (3.2 volts) before overload, so

safe.

al1

Next, reroute

the submasters.

entire monitor section for a stereo echo-

the send. For a master stereo-send, we'll use the

"studio" monitor on the 3-way switch there. Echo return will be

in the

where you will assign the "dry" signal from the

inputs. We now can't "hear" what we are doing and we monitor, so we use the electronics in the 2-track recorder. Route the playback signal to "aux in" and select "aux in" on the

Now, switch from "tape" to source on your track and your whole system

norma1 way - effects-receive 1 and 2,

direct-outs to the tape-ins on

This will now allow you to use

control group and select "mix"

have only one problem left - we

need

"control room" group.

ready to go.

Page 36

AN UNORTHODOX PATCH FOR REMIX WITH STEREO ECHO CAPABILITY

Set "studio" to use as rnaster

track Electronics

via "Aux in"

These controls

rare bypassed rnurnbered 1-8

"rnix"

All monitor selects to "tape",

whole section

is now

Pull jurnpers, use accessory Recieve as input

frorn

echo as

tracks

respective tape ins.

L"directn button now acts as

mute echo send when up. Button rnust be down to

enable Stereo echo send.

[master Echo receive

in Stereo

When unorthodox patches are used and the con- cidents from happening because you have tried sole top panel labels are no longer correct, we to operate the

M-35

"normally". It

also

wise

strongly recommend that you take the time to to lable both ends of every cable. When re-patch-

re-label each csntrol to correspond to the new

function that your re-patch has provided. Draft-

ing tape applied to each group will prevent ac-

ing away from and back to "normal",

endless tracing and retracing of cables

save find out where they gart from.

label will

Page 37

IC OPERATION

(PIN DISTRIBUTION AND LOGIC DIAGRAM)

NJH4559D Dual cornparator

CONNECTION

(TOP

VIEW)

HD7400 Quad cornparator

CONNECTION EQUIVALENT CIRCUIT (BASIC CIRCUIT)

EQUIVALENT CIRCUIT (BASIC CIRCUIT)

-3

OUTPUT

GND

(TOP

VIEW)

VCC

48 4A

38 3

Page 38

TASCAM

TEAC

Production Products

TEAC CORPORATION OF AMERICA 7733 TELEGRAPH ROAD MONTEBELLO CALIFORNIA 90640 PHONE (21 3) 726-0303

TEAC AUSTRALIA PTY., LTD.

165-1 67 GLADSTONE STREET SOUTH MELBOURNE VICTORIA 3205

PRINTED IN JAPAN 0381 SA.99 D-3671

PHONE 699-6000

Tascam M-35 Operation And Maintenance Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual