Sima SVS-1B Instructions Manual
Sima Products Corporation
140 Pennsylvania Ave,
Bld #5, Oakmont PA 15139
412-828-3700 800-345-7462
www.simacorp.com
2003 Sima Products Corporation
Printed in USA
p/n 21695 rev 03.09
TM
SVS-1B Volume Stabilizer
now with Enhanced Sound Circuitry
User Manual
TM
SVS-1B Volume Stabilizer
now with Enhanced Sound Circuitry
Sima Products Corporation
140 Pennsylvania Ave,
Bld #5, Oakmont PA 15139
412-828-3700 800-345-7462
www.simacorp.com
2003 Sima Products Corporation
Printed in USA
p/n 21695 rev 03.09
User Manual
2
Limited Warranty
Sima Products Corp. (“Sima”) warrants that if the accompanying product proves to be
defective to the original purchaser in material or workmanship within 90 days from the original
retail purchase, Sima will, at Sima’s option, either repair or replace same without charge (but no
cash refund will be made). To enforce warranty you must deliver, mail or ship the product,
together with both the original bill of sale and this limited Warranty statement as proof of warranty
coverage to:
Sima Products Corp.
Att: Customer Service
140 Pennsylvania Ave. Bldg. #5
Oakmont, PA 15139
Phone: 800-345-7462 FAX : 412-828-3775
It is recommended that you call Sima at the number listed above to obtain a return
authorization number.
Limitation of Liability and Remedies
Sima shall have no liability for any damages due to lost profits, loss of use or anticipated benefits, or other
incidental, consequential, special or punitive damages arising from the use of, or the inability to use, this
product, whether arising out of contract, negligence, tort or under any warranty, even if Sima has been advised
of the possibility of such damages. Sima’s liability for damages in no event shall exceed the amount paid for
this product. Sima neither assumes nor authorizes anyone to assume for it any other liabilities.Some states
do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation or
exclusion may not apply to you. This warranty gives you specific legal rights, and you may also have other
rights which vary from state to state. Volume Stabilizer is a trademark of Sima.
2003 Sima
Typical Questions (cont.)
Why are the attack and decay time constants different?
The attack time is the time for the SVS-1B to respond to an increase in volume. It needs to be
very fast in order to “catch” a sudden burst of music. The attack time constant of the SVS1B is 2 msec ( 0.001 seconds) and is an exponential shape so that the slope (change of
db per second) increases with larger changes of music volume. Therefore, a loud burst
will cause the unit to reduce the volume more quickly than a small volume change. This
provides a more natural sound.
The decay time is the time for the SVS-1B to turn the volume “up” after loud music. This is
much longer (about 5 seconds) than the attack time. The slope is constant so the volume
changes smoothly, just as you would do. This prevents “pumping” and “breathing” sounds
associated with conventional compressors and other such devices.
23
Sima Products Corp. (“Sima”) warrants that if the accompanying product proves to be
Limited Warranty
defective to the original purchaser in material or workmanship within 90 days from the original
retail purchase, Sima will, at Sima’s option, either repair or replace same without charge (but no
cash refund will be made). To enforce warranty you must deliver, mail or ship the product,
together with both the original bill of sale and this limited Warranty statement as proof of warranty
coverage to:
Sima Products Corp.
Att: Customer Service
140 Pennsylvania Ave. Bldg. #5
Oakmont, PA 15139
Phone: 800-345-7462 FAX : 412-828-3775
It is recommended that you call Sima at the number listed above to obtain a return
authorization number.
Limitation of Liability and Remedies
Sima shall have no liability for any damages due to lost profits, loss of use or anticipated benefits, or other
incidental, consequential, special or punitive damages arising from the use of, or the inability to use, this
product, whether arising out of contract, negligence, tort or under any warranty, even if Sima has been advised
of the possibility of such damages. Sima’s liability for damages in no event shall exceed the amount paid for
this product. Sima neither assumes nor authorizes anyone to assume for it any other liabilities.Some states
do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation or
exclusion may not apply to you. This warranty gives you specific legal rights, and you may also have other
rights which vary from state to state. Volume Stabilizer is a trademark of Sima.
2003 Sima
Typical Questions (cont.)
Why are the attack and decay time constants different?
The attack time is the time for the SVS-1B to respond to an increase in volume. It needs to be
very fast in order to “catch” a sudden burst of music. The attack time constant of the SVS1B is 2 msec ( 0.001 seconds) and is an exponential shape so that the slope (change of
db per second) increases with larger changes of music volume. Therefore, a loud burst
will cause the unit to reduce the volume more quickly than a small volume change. This
provides a more natural sound.
The decay time is the time for the SVS-1B to turn the volume “up” after loud music. This is
much longer (about 5 seconds) than the attack time. The slope is constant so the volume
changes smoothly, just as you would do. This prevents “pumping” and “breathing” sounds
associated with conventional compressors and other such devices.
232
22
What is the difference between the SVS-1B Volume Stabilizer and compressors,
companders, limiters, expanders, and automatic gain controls?
The key difference is in the purpose of how each used.
- Compressors are typically used for two reasons: 1) To be part of a COMPANDing system to
eliminate tape hiss (in which music is COMPressed then recorded on to tape and exPANDED
when played back) and 2) To make radio stations sound as loud as possible. Here multi
band compressors are used which maximize loudness at the expense of affecting the
spectral content of the music; hence everything sounds flat and dull. The Volume Stabilizer,
on the other hand, has been designed to provide an improved sound for listening.
- Limiters simply clamp audio signals above a certain level, thus removing all music dynamics.
These are typically used at radio station to stay within FCC modulation limits.
- Expanders increase the dynamic range of music. These were popular when all music had to
be compressed to fit onto LPs and tapes (with 45 to 65 db of dynamic range). Now with
CDs, HiFi Video tape, DAT, MiniDisc, and DCC, it is no longer necessary to compress the
source. Music is now recorded with its full dynamic range.
- Automatic gain control devices are compressors with an infinite compression slope, so they
completely remove the dynamic range from music. In the MAX position, the SVS-1B also
provides a flat output vs. input, yet retains the instantaneous dynamics of the music.
Typical Questions
3
Warning
- To prevent fire or electric shock hazard, do not expose the
unit to rain or water.
- Use only with the supplied power transformer.
- Do not cycle power at high volume settings as this
could possibly cause loud turn on/off surges
This package includes:
The SVS-1B, AC adapter, an audio connecting cable and this
manual. If any of these items is missing or damaged, contact
Sima customer service at 800-345-7462.
22
Typical Questions
What is the difference between the SVS-1B Volume Stabilizer and compressors,
companders, limiters, expanders, and automatic gain controls?
The key difference is in the purpose of how each used.
- Compressors are typically used for two reasons: 1) To be part of a COMPANDing system to
eliminate tape hiss (in which music is COMPressed then recorded on to tape and exPANDED
when played back) and 2) To make radio stations sound as loud as possible. Here multi
band compressors are used which maximize loudness at the expense of affecting the
spectral content of the music; hence everything sounds flat and dull. The Volume Stabilizer,
on the other hand, has been designed to provide an improved sound for listening.
- Limiters simply clamp audio signals above a certain level, thus removing all music dynamics.
These are typically used at radio station to stay within FCC modulation limits.
- Expanders increase the dynamic range of music. These were popular when all music had to
be compressed to fit onto LPs and tapes (with 45 to 65 db of dynamic range). Now with
CDs, HiFi Video tape, DAT, MiniDisc, and DCC, it is no longer necessary to compress the
source. Music is now recorded with its full dynamic range.
- Automatic gain control devices are compressors with an infinite compression slope, so they
completely remove the dynamic range from music. In the MAX position, the SVS-1B also
provides a flat output vs. input, yet retains the instantaneous dynamics of the music.
3
Warning
- To prevent fire or electric shock hazard, do not expose the
unit to rain or water.
- Use only with the supplied power transformer.
- Do not cycle power at high volume settings as this
could possibly cause loud turn on/off surges
This package includes:
The SVS-1B, AC adapter, an audio connecting cable and this
manual. If any of these items is missing or damaged, contact
Sima customer service at 800-345-7462.
4
Table of Contents
Subject Page
Warranty ................................................................................................... 2
Introduction .............................................................................................. 5
Product Overview ................................................................................... 6-9
Installation .......................................................................................... 10-13
Operation ........................................................................................... 14-15
Technical Information ......................................................................... 16-19
Trouble Shooting ..................................................................................... 20
Specifications .......................................................................................... 21
Typical Questions ............................................................................... 22-23
Specifications
Frequency Response 20 Hz to 20 KHz, +/-3 db
Signal-to-noise ratio More than 70 db, A weighted
Total harmonic distortion Less than 0.2 % THD at 1 KHz
Input impedance 200 Kohm
Input level 0.55 V rms
Output impedance 1 Kohm
Maximum input level Greater than 2 V rms
Channel separation More than 60 db
Volume stabilization effects
@ Max
Maximum gain +20 db (input = .25 mv rms [ -70 dbm])
Maximum reduction -20 db (input =3 V rms [ +12 dbm])
Volume Stabilization ratio Norm - 2:1Max - approx. 10:1 to 1
Zero gain level 0.35 V rms
Signal polarity Positive (non-inverting)
Time constants
Attack 2 msec
Decay About 5 seconds
Power requirements 12 vdc, 200ma
Transformer input 120 vac, 7.2 VA
Unit dimensions Approx. 5.5" x 4" x 1.6" (w/d/h)
Operating temperature 40 to 110 deg F
Supplied accessories Power transformer with 6' cord
21
4
Table of Contents
Subject Page
Warranty ................................................................................................... 2
Introduction .............................................................................................. 5
Product Overview ................................................................................... 6-9
Installation .......................................................................................... 10-13
Operation ........................................................................................... 14-15
Technical Information ......................................................................... 16-19
Trouble Shooting ..................................................................................... 20
Specifications .......................................................................................... 21
Typical Questions ............................................................................... 22-23
Specifications
Frequency Response 20 Hz to 20 KHz, +/-3 db
Signal-to-noise ratio More than 70 db, A weighted
Total harmonic distortion Less than 0.2 % THD at 1 KHz
Input impedance 200 Kohm
Input level 0.55 V rms
Output impedance 1 Kohm
Maximum input level Greater than 2 V rms
Channel separation More than 60 db
Volume stabilization effects
@ Max
Maximum gain +20 db (input = .25 mv rms [ -70 dbm])
Maximum reduction -20 db (input =3 V rms [ +12 dbm])
Volume Stabilization ratio Norm - 2:1Max - approx. 10:1 to 1
Zero gain level 0.35 V rms
Signal polarity Positive (non-inverting)
Time constants
Attack 2 msec
Decay About 5 seconds
Power requirements 12 vdc, 200ma
Transformer input 120 vac, 7.2 VA
Unit dimensions Approx. 5.5" x 4" x 1.6" (w/d/h)
Operating temperature 40 to 110 deg F
Supplied accessories Power transformer with 6' cord
21
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