The IGS Alter 500-Series Compressor is an FET compressor built is the 500 standard. The FET-type solution was used for the first its application in the legendary UREI 1176 compressor from the 70s. The Alter is a single-channel unit with stepped input and output controls. The Ratio switch has six positions, including two additional to the original 1176 1:1 and 2:1 settings. Slam Mode can be turned on with a separate switch, working regardless of the Ratio settings. Attack and release times can be set to Fast / Mid / Slow with 3-pole switches. The IGS Alter 500-Series Compressor is equipped with a relay bypass, achieved on the front panel. The input is balanced with a modern, low-noise op amp and the output with a custom IGS transformer transformer. The circuit has two amp stages, between which is the output control. The stage amps are based on the discreet API2520 circuit. The level of gain reduction is shown by a 20 point led bar.

Input – Input level and compression depth

Output – Output Level

Attack – Variable Attack – 3 ranges: 0.02, 0.2 and 0.8 ms

Release – Amp recovery time to the value of 0.85 max. Range: 50ms, 600ms, 1.1 sec

Ratio – compression ratio over the threshold response

Ratio ranges: from 1:1 (line amp), through 4:1 (compressor) to 20:1 (limiter)

SLAM – allows the enabling of All-Buttons-On – the “secret weapon” of any studio engineers 😉

COMP IN / OUT – Enable Bypass relay device

GR – very fast LED indicator showing the compression level in the range from 0 to 20dB

IGS Alter 500-Series Compressor Specifications

Device Type:

FET Compressor: Yes

Basic Features:

All Stepped Manipulators: Yes

Input & Output:

Input Impedance (Balanced): 10k Ohm

Output Impedance (Balanced): 600 Ohm

Audio Transformers: Yes, IGS’s own custom transformer

Levels:

Operating Level: +4 dBu

Max Input Level: +20 dBu

Max Output Level: +22 dBu

Noise Level: -99 dBA

Max. Gain: 36 dB

Max Gain Reduction: 20 dB

Time Constants:

Attack: 20us, 400us, 800us

Ratio: 1:1 to 20:1

Release: 50ms, 600ms, 1.1s

Bandwidth:

Fequency Response: 8 Hz to 20 kHz, +/- 0.1dB

Distortion (@ 20 Hz – 20 kHz):

THD+N: 0.012%

Power:

Power Consumption: 2.5W

Packing Box:

Shipping Weight: 1 kg / 2.2 lbs

IGS Alter 500-Series Compressor Includes