Iso-Max SC-2NR, SS-2NR, SP-2SX User Manual

ISO-MAX®

PRO

SERIES

USER

GUIDE

SPEAKER-LEVEL

Models

Jensen

ISO-MAX8 Pro

They

use the
recording studios, broadcast facilities, and sound reinforcement
bandwidth,

same

an

series

audio interfaces are designed for use

industry-benchmark

vanishingly low harmonic and

Jensen

SC-2NR,

transformers that are installed in tens of thousands of the world's best

phase

to

LINE-LEVEL

SS-2NR

distortion.

Interfaces

and

SP-2SX

in

the finest professional and audiophile sound systems.

venues

because

of their

sonic

transparency, ultra-wide

Model

SP-2SX

Models

SC-2NR
isolators - the
(shown above)
selectable ranges,
output

of

W,

or

1,500 W respectively
covering large
outputs

are actively driven and cannot be grounded (these are often referred to

The

speaker

W,

1.5

W, and
remove ultra-sonic switching artifacts from the outputs
subtle distortions in downstream amplifiers [Deane Jensen

85th Convention Preprint 2725,1988}.

The standard versions
The

SC-2NR

power

amplifier

audio

systems

outputs

will

nominal

"Mono"
the

two

speaker

output,

L + R,

and

SS-2NR

SS-2NR

is

the functional equivalent

speaker

power amplifiers rated

areas.

inputs represent a trivial additional load for the driving power amplifiers - maximum input power

5.4 W

and

SS-2NR

with

where the nominal

reach 6.9 Vrms (+19 dBu), a level that represents

or

"reference level"

output versions, denoted

input

drives a single

are two channel

having an extended low-frequency response for extremely high-performance sub-woofers. The

drive voltages

at

24 W,

into

4 O

loads. Input

Since

the

speaker

respectively in the four input ranges.

have

dual,

or

"stereo," outputs that correspond independently to

output

signals

an

unbalanced input to

or

signal

is

by a

signals.

These

would

sub-woofer.

"speaker"

with

of

14 Vrms,

75

W, 240 W,

inputs are ungrounded, they are especially useful

will

reach 1.75 Vrms (+5 dBV)

full

"reference level"

standardized at

"-M"

suffix in the model number,

be

used, for example, when the inputs are Left and

level to unbalanced "consumer" level converters and ground

balanced "pro"level outputs. All are designed to accept, in four switch-

25

Vrms, 44 Vrms,

or

750 W respectively

ranges

also

include

In

addition, all models provide inherent low-pass

of

"digital"

and

output power.

signal

is

standardized

15 dB of

+4

dBu

or

SP-2SX

or

77 Vrms.

25 V

and 70 V lines

or

"class

D"

Gary Sokolich, "Spectral Contamination Measurement," AES

at

maximum rated input - sufficient to drive any known

This

level represents

at -

"headroom"

1.23 Vrms.

have a single

These

voltages

into

8 Q

loads

or

used

in

with

as

"bridge-mode"

power amplifiers.

each

15 dB of

10 dBV

or

0.316 Vrms. Likewise, the

in

professional audio

output that represents the sum

will

be

developed at

rated at 48 W, 150 W, 480

commercial sound

power amplifiers where both

or

"floating" outputs).

is

0.08 W,

filtering

These

artifacts can

of the

speaker

"headroom"

Right

channels and the

input

in

consumer

systems

full

systems

0.4
to
cause

signals.

SP-2SX

where the

of

These

ISO-MAX

units are entirely

FOR

OPTIMUM

PERFORMANCE,

passive

and require

no

power supply.

PLEASE

REVIEW

THE

FOLLOWING

PAGES!

General

Load

Impedance

Application

Range

Guidelines

(input

impedance

of device the unit drives) 10 kO or more

Maximum

Maximum

System

In choosing a physical location for the
cables.
"speaker
gauge
the
can be connected to either the main-channel power amplifier output terminals or the main-channel
whichever is
across
each

FortheSC-2NRor

Observing polarity, securely attach the

channel and screw terminals 8 (+) and 9 (-), marked "CH 2 IN," for the other channel.
SPEAKER

connect a standard, high-quality RCA male to RCA male

power

Output

Input

Cable

Length,

Cable

(amplifier/speaker to

SC-2NR

and

SS-2NR

ISO-MAX)

60 feet (18 m) of typical

SP-2SX

3 feet (1 m) of typical

Length unlimited

cable

at 50 pF/ft (160 pF/m)

total

capacitive load <

cable

at 50 pF/ft (160 pF/m)

total

capacitive load < 200 pF

Hookup

ISO-MAX

In general, the better location

wire"

is recommended for the

are generally

quality of sound - normal technical concerns about

the "constant voltage" distribution line. Again, be sure to observe polarity and tightly twist the strands of wire at

end to avoid strands that "stray" beyond the clamp

INPUT

amplifier(s) to be driven.

easiest

closer

or more convenient. For 25 V or 70 V distribution systems, make the

SS-2NR:

CABLES

to strip and handle. It should be emphasized that the quality of this wire has negligible effect on

ARE

CONNECTED

will

speaker

speaker

unit,

shorter output

be near the amplifier(s) to be driven. Inexpensive,

inputs to the

speaker

area

input

cables

to screw terminals 1 (+) and 2 (-), marked "CH 1 IN," for one

TO THE

CORRECT

TERMINALS - OTHERWISE,

cable

cables

are preferred over shorter input

unit.

Its

gauge

is technically unimportant but 18, 20, or 22

cables

do not apply. The other

"speaker"

of either the screw terminals or amplifier/speaker terminals.

DOUBLE

THE

between the

ISO-MAX

unit outputs and the inputs of the

small-gauge

ends

connections directly

CHECK

UNIT

MAY BE

"zip cord" or

of these input
speaker

TO BE

DAMAGED!

3,000

(speaker

cables

terminals,

SURE

THE

pF

feed)

Finally,

FortheSP-2SX:

Observing polarity, securely attach

"2-pole"

ISO-MAX

described below.

The Screw

If

parallel the input and output connectors, if present. Note that terminal numbers

cable

connector (not supplied).

unit

will

not accept 4-pole

Terminal

desired, all input and output connections can be made via the detachable 13-pole screw-terminal strip.

Terminal

13

12 CH 2, OUT -

11

10 CH 2, IN S

9

8 CH 2, IN +

CH 2, OUT +

CH 2,

CH 2, IN -

Strip

Marking

OUTS

each

speaker
Please

cable

feed

note that the mating Neutrik model

connectors. Alternatively, the screw terminals may be

(all models):

Function

Channel

Channel

Channel

(no internal connection)

Channel

Channel

2,

Line

Output +

2,

Line

Output - (cable shield for unbalanced output models)

2, Output

2,

Speaker

2,

Speaker

cable

to terminals 1 (+) and 2 (-) of a Neutrik

Shield

(internally tied to unit

Input

-

Input

+

NL2MP

descend

housing/chassis)

panel connector

used

in

left-to-right

"Speakon"

for

order.

model

used

speaker

These

NL2FC

on the

input as

connections

7

6

5

(CHASSIS)

CH 1, OUT +

CH 1, OUT -

Unit

Channel

Channel

housing, internally tied to Output

1,

Line

Output +

1,

Line

Output - (cable shield for unbalanced output models)

Shields

(see "Grounding"

discussion

below)