The Alesis 3630 is a rack-mount compressor: a two-channel RMS/Peak compressor limiter with a built-in gate, with both channels fitting in a single rack space. Alesis describes it as providing "two independent full-featured compressor/limiters in one rack space," and it can run as a stereo-linked pair or as two separate mono compressors. Alesis lists the unit as discontinued.1
The controls and ranges
Each channel carries Threshold, Ratio, and Output controls, with a 12-segment LED meter for level. The threshold runs from -40 to +20 dB, and the ratio spans 1:1 to inf:1, so the unit covers everything from gentle leveling to full limiting. Attack time is 0.1 to 200 ms, program dependent, and release runs from 50 ms to 3 sec. Alesis also offers a choice of Hard or Soft Knee dynamic curves: a soft knee eases into compression as the signal approaches the threshold, while a hard knee clamps at full ratio once the threshold is crossed.1
| Control or parameter | Range |
|---|---|
| Threshold | -40 to +20 dB |
| Ratio | 1:1 to inf:1 |
| Attack | 0.1 to 200 ms, program dependent |
| Release | 50 ms to 3 sec |
| Output | gain control |
| Knee | Hard or Soft Knee dynamic curves |
| Metering | 12-segment LED |
Stereo link and sidechain
The 3630's two channels can be set to Stereo Link or Dual Mono operation with individual Bypass. In stereo link mode both channels respond together, which keeps a stereo image from shifting when one side is compressed harder than the other; in dual mono each channel works on its own and can be bypassed separately. A sidechain jack on a 1/4" TRS connector lets an external signal control the detection circuit.1
In the box and the manual
Alesis lists the included items as a Power Supply and a Quickstart Guide. The full 3630 Compressor Reference Manual is available as a PDF from Alesis at alesis.com/rscdn/980/documents/3630_manual.pdf.1
Alesis lists the 3630 as discontinued, so the unit is no longer in current production.1
For players used to pedal-format dynamics, the 3630 belongs to the same family as compressor pedals, but in a rack format with two channels, a gate and a sidechain1.
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Questions
Can the Alesis 3630 be linked for stereo?
Yes. The 3630 is a two-channel unit and Alesis lists Stereo Link or Dual Mono operation with individual Bypass. In stereo link mode the two channels track together so a stereo signal is compressed as one, while dual mono lets each channel work independently with its own bypass switch.
Is the Alesis 3630 still in production?
No. Alesis lists the 3630 Compressor as discontinued on its product page. The unit is no longer made new, so players looking for one are dealing with the used market.
Does the Alesis 3630 have a sidechain input?
Yes. The 3630 has a sidechain connection on a 1/4-inch TRS jack, which lets an external signal drive the compressor's detection.
What is the ratio range of the Alesis 3630?
The ratio runs from 1:1 all the way to inf:1. At the low end the compressor barely acts, and at inf:1 it works as a limiter, holding the signal at the threshold.
Where can I find the Alesis 3630 manual?
Alesis hosts the 3630 Compressor Reference Manual as a PDF on its own site, at alesis.com/rscdn/980/documents/3630_manual.pdf.
Sources (1)
- Alesis 3630 Compressor, Alesis, 2026