Hi everyone,
I'm experiencing breakup when using the Jam Pedals Dyna-ssor Compressor, but only when playing through my pedal steel guitar — it sounds fine with regular guitar. So I suspect the issue is due to insufficient headroom in the pedal.
Are there any compressors specifically designed or well-suited for pedal steel guitar?
Also, how can I determine a compressor's headroom just by looking at product specs or documentation?
On your second question, some compressors specify the "nominal input level" which might be somewhere close to the clipping threshold (above there and you could get distortion.) And some compressors use higher working voltages to give more headroom, look for 18V or 24V internal operation derived from the usual 9V input. Example: Cali76 uses 24V internally, and says it's compatible with line level. That's a little ambiguous, and could mean either pro line level (roughly 1.2V ) or consumer line level (roughly 0.3 V), but either way it's higher than instrument level (roughly 0.075V.) Example: Boss CP-1X uses 18V internally for greater headroom, but specifies an instrument level input (0.075V.)
On your first question, I've only ever used one compressor (Empress) and it doesn't distort with my lap steel humbucker. It converts the 9V input power to 18V internally, and has an advertised headroom of +15 dBu which is roughly 4V.
Long-time guitar player, currently being schooled by a lap steel.
I'm completely happy with the Keeley Compressor Pro, all the performance and control I looked for when I was mixing for a living, packaged in a 9vdc pedal.
Distortion in a compressor circuit can come from at least three sources
1. Rail to rail voltage as already mentioned
2. Distortion internal to the gain element - optical, OTA, FET, or VCA chip
3. Sidechain design and how it interacts with the gain element
The common MXR/Ross/clone Dyna Comp that uses an OTA can have noticeable distortion with pedal steel and also have very primitive side chains that are part of the issue.
Optical and VCA tend be much cleaner, especially with well designed side chains. FET can also be clean with the correct design like the famous 1176.
I manufacture an optical compressor designed specifically for pedal steel you can check out on my website.
I like to place a steel compressor after the volume pedal. Otherwise, you’ll hear the compressor clamping down (or in your case distorting) just from picking a little harder. In my view, it should put a finishing touch or boost on the whole signal, and not just the dynamics of your right hand.
I've used MXR Dyna-Comps for Tele (right before the VP) time out of mind, and no complaints at all. Tried one with steel and it was un-useable. The Keeley Compressor Plus worked better on steel, enough to get by live if the sustain was far enough back, but what worked best was an Alesis 3630 limiter. They're out of production now, but I'm sure there are equivalents being made.
