Collins 30L-1_revisited_1995.pdf Collins_30L-1_revisited_1995.pdf

BY

BILL

ORR, W6SAI

Radio

THINGS TO LEA

In the early 1960s Coll ins

troduced the mode!
amateur
boxed a

HF use. This was a unique design. It

1 kilowatt

3OL-

PEP

FUNdamentals

RN

RadioCompany

1linear

amplifier and power

, PROJECTS TO BUILD, AND GEAR TO USE

The

amplifier for

Collins

in-

30L-1

Amplifier

Revisited

supply in

lar

KWM-2

as a companion unit to the transceiver,

Prooecuon

ago
on

feted

will wOfk with

fiers hit the market.

the

operation, and also by NATO, who fitted the

, but the amplifier has remained a favorite

the second-hand market. The few units

tOf

by eager amateur radio operators anxious to

have a well-designed,

Recently.a large contingent

military.

amplifiers into a transportable communication
system.

lhe

sale are snapped

same size cabinet as the popu-

transceiver. In fact, it

of

the

tooeve

who

3OL-l

used

modern transceivers,

These

them

ceased

up

compact

were released

in

was

at a good price

01301..-

the

designed

some

amp

Desert

lifier that

1ampli-

years

01-

by

Storm

The

Collins 30L- I linear amplifier introduced in the early t960s.

In general ,

in

good

dents in the fragile aluminum case. The units
were snapped
by

dealers who resold them
were not
liers hit

Since the exact use of the amplifiers
unknown (as far as frequency is concerned),
and the amount of maintenance quest ionable,
I'm
ments you might consider beforeyour amplifi­er is
gained by

the air myself.

of

put

The

The3Ol..-1 amplifieruseslour
odes in parallel in a

amplifier covers the range of
five bands, It is theoretically possible to
ate at any frequency in
the

cathodeinput crcurts

aling frequency,

The amplifier power supply is normally con­nected
connections
operation . Under normal operation,
plate voltage is 1800,

vons

An antenna chan
porated inthe
from the
also provided.

Under
mended)

rent at about
equates to a plate input of
the drive

it actually reaches an input of 1kW

The user of a

not have the overload capabilityof

shape , aside from some

johnny

the market.

fering some

on

30L·l

for 115 volt operation, but the primary

under full output.

uanscever. An

the amplifier draws

power

the

newly

up

, some by hams, and others

-orHhe~spot

maintenance

the air. The

pulling

one

Amplifier

grounded

may

3OL-1

key-down operation (not recom-

be

geoverNOX

sothat

surplus amplifiers are

bangs

to

the fellows who

when the ampli-

and

100IOw

of the surplus units on

ing material was

and

adjust-

Circuilry

8l1A

grid circuit. The

3.4

mat

are

changed

dropping

ALe

range , provided

tuned

itmay be controlled

control circuit is

600

high-mu tri-

to 30 MHzin

oper

to

the

ope

for

230

standby

to about 1600

relay is incor-

rna platecur-

von

is

1600 volts anode potential. This

960 watts Some of

is fed through the amplifier, so

PEP.

3OL..1 is cautioned that it

many

does

mod-

em

pact
up

or
this amplifier for the last available watt, as

does not have the reserve.

amplifiers. Because

design. there is very Iitle margin for tune-

erroror overload in either the power

the

81

1A tubes . Don't

01

the size and

be

greedy and push

supp

com-

ly

it

won't play!
two outer lugs of a terminal strip located near

resistor

You
and
wired. The next
tubes. Eyebafl them.
wire bouncing around inside the tube as you

now

the line vOltage for which the amplifier is

The fuse wire is mounted between

Rll

in the powersupplycompartment.
know the protective fuse is okay

step

is

to

LOOk

check

lor

little pieces

the

8llA

01

Preliminary Checks

rotate

On The

Beforeyou tumon the amplifier ,therearesome
checks you
ation, First, you should
amplifier is wired for 115 or
This can
the resistance between the two
the

power

230 volt operation, the resistance will be about

2.2 ohms. The resistance w

-

for 115 volt operat ion.

Nextyoushouldremove the 811Atubes and

eyeball

Amplifier

srouro

be

done

cord. If the amplifier is

them

. It the glass envelope of a tube

run

to

ensure proper oper-

check

with an ohmmeter. Measure

to see if the

230volt operation.

blade

strapped

itl

be about 1ohm

pins

on

for

a

section of the filament or grid
the tubeis usetess Clean
with a

scraped the pms

to
check

conductance
should

on the checker.

Finally ,
the blower motor bearings with a few
machine oil.

-

is

gray
many
tionable.
the plate, it indicates the tube has been over­loaded. It is prudent to
More

Once you have removed all tubes, useyour
ohmmeter to measure the resistance fromone
filament pin socket (one of the large ones)
ground, It should be near-zero ohms. You are
checking
cuit (not
tioned in Section 4.1

is a short length of No.

return of the filamen t winding of the power

nanstomer.

from excessive current. It is rated at
steadycurrent and will blowat about

Whether this protects the tubes is question-

ab

le, Ifthe four 811As draw 1000

instead

hours of use

If there are burned. bright spots on

on tube selection later.

out a luse in the filament return cir-

shown

of

clear. it means the tube has

and

on

the schematic, but

its operation is ques-

replace such a tube.

of

the manual). This luse

30 wire in the

It will

blow

and protect the 811As

l000ma.

ma

to

men-

ground

700 rna

even for

Primary Power For The 30L-l

The amplif ier operates from a 115/230 volt,

Hz powerline .For best regulation, it should be

run on a

Over
signed, the utility companies in the
gra

rnooate

myhome,

most
volts on the 115 volt amplifier primary circuit,
or 14 volts on the

No
situation is

with little tolerance lor tuning
the power
8l 1Atubes are working attheirmaximuminter-

mittent rating at the desi

it. Ifsuch wires are visible. it means that

rs

broken and

the glassof the tube

damp

remove

If you

can

the tube. I used a surplus

give

230

the years, smce the 3OL·l was de-

rag and clean the base pins I

With

co

rrosion.

lay your hands on a tube tester,

the

blade

01

a small knife

TV-7

checker for

approximately the same reading

check

vOlt

the line fuses and lubricate

circuit.

my

tubes. They all

U.S.

dually been boosting line

increased loadson existingcircuits. In

forexample. Imeasure 1221244volts

01

the day. This results in overage of 7

voltagetoaccom

230 volt circui t.

big

deal, you mi

otherwise. The 30L-1 is designed

nans

torrer. fitter capacitors,

gh

t say. Howev er, the

error

gna

.In addition,

ted voltages.

trans-

drops

have

and

of

60

-

4B Campbell Lane. Menlo

f>4

•

co

• Nov

em

ber

Par#(,

1995

CA

94025

short period, at least

In any event, if the fuse is

oneor

morewillbe ruined,

blown, the amplifer

am

Running the
jects the amplifier components to a

plifier at

my

Say

line

Yo

u

po

Saw

tential sub-

7 percent

It

In

CO

The primary of the transfor

mer

is

con

nect-

secondary

rel

ay

activates the VOX circuitinthe

T1

Line

I

Line

N(IGl'l

Fig,

1- Primary eutotonr eris a filament trsns-

tamer wired so

down to the proper

transfcxmerisinserieswithone

overload. This e
limits on the t
besides

very

sostressing ItfurtherISa risky
recommend It.

A

hot. The amplifier runs hot

Primary

N)

makin

;¥;

as

to

buck

value,

xceeds

ube

g the

filaments and

the

power

Autoformer

Secondary

volta

opera

-,

Line

./

Un

e

(GRN) ( N

the line voltage

of

the

side

transformer run

enough

of

the

ge

tolerance

capaci

as it is,

tion. fdon't

line,

tors,

ed across the line, and the s
series with the line. If the
lions
boosted

of hitting it right the first time .

your line volta
amp

234 volts, Close enough. For
you'll
mary
surplus octtus.

Amplifier

The
antenna
That relay

or "VOX'

the 30L-1 obtains its voltage from the
bias supply, The relay coil draws abou t 85 ma

current.
the transceiver.

use
er'schangeover relay,while others use a small

mec
rated for the volt

are

If you are

transformer will

need

. That

incorrect.

by

7.5 volts.
wired

ge

a transformer with a

may

VOX CirCUitry

3OL-1

It

may
a

power

hanical relay the

has

changeover

can

Ci

rcuit of the transceiver. The relay in

be

an mtemat relay that controls

be

risky 10 key this relay

transistor to actuate the amplifi-

the

Youhavea50-SOchance

for

is

244

buck

be

a sticky wicket

activated

Some

contacts

age

and

secondary

line

230

and

makes

volt

as mine is, a 10 volt, 5 the re is

the voltage down to

cur

econda

voltage

opera

230

standby

by

of which are

rent requi red by

volt service, rent

220

the

directly

of

transceivers

ry is in 30L-1,The relayand a 9 volt battery are

connec-

will

tion,

volt pn-

Check

circuitry

"Re

mote-

- t70 volt

from

be

and

the

no

place

in a small aluminum

235)

input
Simple msrauatco.
rear

circ

The 811A

Power

The 811 triodewasb
late 1
audiO service. The

.

t

c.secetco
tme

which was the s

ing fins

dissip

of 65
a

dull
Four 811As, ofcourse,
sipatton rating, or 260 watts w
pr

measuring

plug

case

uitry

drawn

and

of the amplifier

no

danger of damaging the receiver

by the relatively high voltage

by

an

the amplifier relay.

High-mu

Triode

930s

oesicnero

added

atioo rating a bit.

The

811A

watts.At this level t

red color when

oper

ly ventilated,

It

was

raling.

ttnetube)br

ame

to

hasamaomurn

'23/4'

designed

the anode to boost the plate

box
x 2

output

which

rough

tube

and

tube, but with

observed

ha

(Radio Shack 270-

1

/8

' x 15/8

cable

may

by

stickurn tape Now

tto the

mainly

suttereo from

a few years later RCA

oughtout

dissipationra\lng

heanod

ve four times this dis-

', A

complete

be

held

and

mark

et inthe

fOf

low

me

sm

all cool-

e will just

in a

dar

hen

they are

phono

to

class

plate

at t A,

shoW

k roorn.

d

the

the

cur-

B

It is a

11

with an autotormer. A fi

be used, provi
line

as to

used

I

reduced

good

5J23Q

cu

rrent. This transformer is

buc

idea

voIt rating. This can

k the li

a 7.5 volt, 10

my

line voltage 10

ded

ne

to

reduce

the se

voltage (fig. 1l-In

the

line

lame

am

nt tran sformer

co

ndary can

p transformer. This with a 9 volt,

about

be

voltage

a

ccom

conne

114.5. is activ

to the

plis

hed
can

pass

cted

my

the

so uses a transistor or a relay as a VOX

case, suit

3OL-l circuit.

It is

orate rel
transce

ableci

test.uer

aythatca

iver, r

ated

egard

rcuit is

tam

by

etcee. to

n

less of

show

e con (RadiO

the transceiver

make

be

safely

wheth

n in fig. 2. A small relay

up

an mt

dr

iven

er that unit The early 8

Shack

circuit,

enre-

by

the

drive

275-0(5)

and this

r. A the

Problems

11

base

desig
t

he

last, sad

was

n a

shooting the

were

nd

manu

With The

A tu

da

be

s with the old R

beautiful

fac

turing.

ys

0/

RCA when the transistor

vacuum

811

examp

How

tube

out

A Tube

CAlogo

les

ever,

of

a/the

tube

du

on

ring

sad-

TM-733A

TH-79AlO) TH-28A TH-22AT

2050

Los

l

TM-241A

S.

Bundy

Angeles

310-820-1234

, CA 90025

Drive

say

You

saw

It

In CO

CIRCLE 27 ON READ£R SERVICE CARD

die, RCA
co

st accountants, rather than the tube engi-

neers,
or so it seems . Late
were
Ceramic plate supports on

rods were removed, the mica support at the

top of the tube anode disappeared, and the

unhappy

succumbe

dict

ate the manufacturing processe

knock-offs of

d to the lure

produc

tions of the 811A

the

the

of

letting the

early desi

vertical

s-

gn

anode

.---------.,

I Ry

.

Sh

ield

ed

ca

ble 10

tra

nsc

eiver

I

I

it

•

"""

NO

,

r'

<J l <

~

1

To 30L-l

<control

(J3)

plate lead from the an

was butt-welded

welded to a sturdy strap.

The "improv

as well as the olderconfiguration, but the inter-

nal structure is fragile and subject to vibration

damage.

Inany event. the 811Aworks to its

capa

be
been

amplifiers have been

another,so this isa
of one of these.

city in the

maoetocercooo

that

some

toa thin wire,instead of

ed"

3Ol-1. so every attempt

of

ode

811A seems

tubes. My experiencehas

the

ma

jor problemfor the owner

strap to the top cap

to

work about

ma

8l1As

cooked

in the

at

one

being

xim

um

snono

surp

t

ime

lus

or

I

I
I

L..

___

Fig.2

wnich
good

out- or-sp

er enclosure of a TS·830. They are too tall.
Others are gassy, or have

factory his tubes

example. Some Chinese 6146$ are so

ec

-lntermed

that they didn't fit into the amplifi-

iate control relay

came!

The 6146 is a

creon.

poor gain.

I

I
I

9v.

I

---_..I

(Ry '" RadioShack 215-005 relay.)

amp
The

against the aluminum chassis .
assing. I eliminated this annoying problem by
filing

lifier sockets, but you

bayonet

oft the pin before I put the tube in the

pin

on

the

ca

n't

tube

get

base

Most

them

cot!

snag s

embar-

A New Version

Some years
opportunity to examine some transmitting
tubes brought

teurwbcvisrtedthat country. Visually,the tubes

seemed
techniqueswereobvious The tubesweretest-
ed

and

and

time were not up to the attractive m
qua

Recently,the
tunity to examine and test tra
made

epublic

R

that the Russians had ma
qua
were inthe questionablecategory

the results were mixed. The

aging

lity of the tubes,

in the new Russia

lity control. and that t

ago

exce

techniques used in the USSRatthat

of China. It was immediately obvious

power tube engineers

back

llent.

lube

of

from the USSRby an arna-

and

eflgineers

The

test-crass

had

nsm

and

also the People's

de

great strides in

he

Chinese tu

811

occupied

A

had

assembly

pumping

ec

hani

the

ocoor

itting tubes

the

ca

bes

by

the last few years. assisted by American

In

expertise .

lass

c
811A

he

t

ic insulator under the plate

glass

hard glass
intended for transmitting tubes. instead of

soft

l

-

Devices,3000 Alpine R
94028: phone
3Ol·l
results
RCA tubes . The four tubes
matched, as all run at approximately the
te

rro

tubes , Including 811As. The Russian

looIl:s like t

addition of a ceram ic

env

glass

FourSvettana8t l As(from SvetlanaElectron

am

erature.

the

elope

envelope of the RCA 8t 1A

plifier.

equa

Russians are lurning

he

good

fromelectrolysis. In a

envelope

415-233.0429)are running in

Ope

lling

those

old

RCAtab, but with

base

is used,

oad

ration is

achieved with the early

,Portola Valley, CA

, and a ceram-

cap

to protect the

un

eventful, the

seem

out

ddi

speci

first-

tion. a
fically

the

my

even

same

ly

amplifier.

Amplifier

Individualpi-network circuitsare used for each
frequency range of the
Changed
surplus ampl ifiers arriving on
ably
amateur bands, it is a g
these

equenc

fr
circuits in my amplifier and found fhey were
funed
Collins manual
these

mistuned results in unusual pla te circuit tuning
and,inextreme circum stances,amplifie roscil­lation.

were

circu

by

Ci

rcuits were retuned to an out-of-band

y at some time. I c

t03

.8,8,6. 16.6,24.1,and30.1 MHz.The

Input

the main bandswitch . Since the

used

its. Operation with the input circuits

on

provides tuning information for

Circuits

30l-1.

the

frequencies

ood

assumpt ion that

hec

They are

market prob-

outside

ked the input

the

the

tubes of

factories in

the

Ch

de

funct USSR. Over a

ina

make

transmitting tubes.

dozen

Some are good; some are not. And the untor-

tunate purchaser

doesn

't know from

A

Word

Regardless of the

migh t find that you

of

Warning

brand

can

A CQ

018l

get the t

lA

4-"

Admtim

you use, you

ubes

into the

\

A

Heartfelt

I really
recei ved urgi

Thank you all,
a bimontly basis. We
ing,my

WB2KFN;

K2BRY; A
W6PYK: Anthony Musero. K3
Beezley, K6STI; Rober t Lorenz, AB6MA; Rod
New

na

Re
Irving

app

kirk, W9BRD; Ed Gilner. W6ZZN: Ronald

ud

Mor

reciate the friendly letters I have

73 and gratifude: Mel Schaefer ,

ThomasHart.

nd

rew Pfeiffer, K1LKO; Paul Scholtz .

. W8FEU; Richard Harmon. KK5BR;

ris, W2GMT; J

"Thank You! "

ng

me

I'll do the best Ican, perh

to

co

ntinue this column.

shall see. To the follow-

ADl

ack

B:ManinWincott ,

UKW

Bennett, W8NEN;

ap

s on

; Brian

Li

keCW?You
paddles, plus
Ea

ch
as-silk
tha

t's a

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K4TW

Own
for

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a full line

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56 •

.~.

co

• Nov

ember

199

5

• •

AL

36606

Fax

N1TEV; Art Roshan, N7ABH; Wayne Cooper.

AG4R;
N6PUG: FrankWitt,
WA

Gary Breed, K9AY;

lWIA.

AllH;and

Say

Greg

Dennis Bernier,

You

Sparacino,

73, Bil"WGSAI

saw

It

In

CO