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Vintage threads from the first ten years

Compressors

9/16/1999 10:42 PM
Mike shaw	Compressors I'm thinking about getting a stompbox compressor. Which are the really natural sounding ones and which are the dogs? I've heard that the Ross and MXR are good, but are there any new ones worth considering? Thanks for any input! Mike

9/17/1999 1:02 PM
Mark Hammer	"Natural sounding" needs some articulating. In general, if one wishes "natural sound", the dynamics of the original signal should be preserved as much as is possible. This would argue against a compressor, and probably in favour of a limiter. The difference is that restriction of dynamic range occurs within a specified range with a limiter. On the other hand, what you mean by natural sounding may simply mean no colouration, no matter how much squeezing of the signal occurs. Here I can't help you, although people seem to like the Orange Squeezer (GEOFEX has the schematic. I think its called the Fresca Splash or something.). People also like the Dynacomp, but the 3080 chip it uses does tend to inject a smidgen of distortion when you push it, but this is part of what people like.

9/17/1999 1:02 PM

Mark Hammer

"Natural sounding" needs some articulating.

In general, if one wishes "natural sound", the dynamics of the original signal should be preserved as much as is possible. This would argue against a compressor, and probably in favour of a limiter. The difference is that restriction of dynamic range occurs within a specified range with a limiter.

On the other hand, what you mean by natural sounding may simply mean no colouration, no matter how much squeezing of the signal occurs. Here I can't help you, although people seem to like the Orange Squeezer (GEOFEX has the schematic. I think its called the Fresca Splash or something.). People also like the Dynacomp, but the 3080 chip it uses does tend to inject a smidgen of distortion when you push it, but this is part of what people like.

9/21/1999 4:43 PM
Mark Hammer	Looking at the posts from the last few days, and doing some thinking, it would appear that we have 3 categories of compressor, each with their pros and cons: 1) VCA-based: This includes anything with a CA3080. LM13600/700 or SSM2165/66 chip in it, and a number of other more exotic designs. Pros - much tighter control over envelope, selective threshold, etc., and if the VCA is high quality, very transparent. Cons - parts not always available, higher parts count (Q&D compressor excepted), and colouration if VCA not high quality (e.g., Dynacomp). 2) FET-based: Any design which uses a FET as a voltage-controlled resistive element to attenuate gain or attenuate input/output signal. Orange Squeezer is primary example. Pros - parts count modest, highly tweakable by amateurs within design constraints, parts cheap and easily found. Cons - susceptible to several sorts of distortion (e.g., IMD from twitchy envelope detector), provides some minimal colouration, can't easily handle high signal levels cleanly. 3) LED/LDR-based: Anything that uses a photocell to provide signal attenuation in the input, output, or feedback loop. Prime examples are the ROSS (as described in the thread), the various Craig Anderton designs, and (without even bothering to look at the schematics) Morley pedals (just a shot in the dark here, but LDR's seems to be their game). Pros - can handle high signal levels, LDR smooths out glitches from envelope detector, minimal colouration virtually regardless of design, simple tweakable design and modest parts count. Cons - parts are sometimes hard to find. From a transparency-at-any-cost perspective, Mike wants a decent VCA-based design. From a transparency-I-can-afford perspective, Mike wants an LED/LDR-based design. This particular analysis suggests that the Dynacomp ought not to have been as popular as it was and still is. HOWEVER, sometimes folks like the colouration that an ostensibly non-colouring device adds. Witness the Joe Meek compressors that are VERY costly, anything but transparent, and just the thing the doctor ordered for many a production. (I'd be curious as to whether the Joe Meek developers have ever considered a floor box, given that they have a few rackmount models).

9/21/1999 4:43 PM

Mark Hammer

Looking at the posts from the last few days, and doing some thinking, it would appear that we have 3 categories of compressor, each with their pros and cons:

1) VCA-based: This includes anything with a CA3080. LM13600/700 or SSM2165/66 chip in it, and a number of other more exotic designs. Pros - much tighter control over envelope, selective threshold, etc., and if the VCA is high quality, very transparent. Cons - parts not always available, higher parts count (Q&D compressor excepted), and colouration if VCA not high quality (e.g., Dynacomp).

2) FET-based: Any design which uses a FET as a voltage-controlled resistive element to attenuate gain or attenuate input/output signal. Orange Squeezer is primary example. Pros - parts count modest, highly tweakable by amateurs within design constraints, parts cheap and easily found. Cons - susceptible to several sorts of distortion (e.g., IMD from twitchy envelope detector), provides some minimal colouration, can't easily handle high signal levels cleanly.

3) LED/LDR-based: Anything that uses a photocell to provide signal attenuation in the input, output, or feedback loop. Prime examples are the ROSS (as described in the thread), the various Craig Anderton designs, and (without even bothering to look at the schematics) Morley pedals (just a shot in the dark here, but LDR's seems to be their game). Pros - can handle high signal levels, LDR smooths out glitches from envelope detector, minimal colouration virtually regardless of design, simple tweakable design and modest parts count. Cons - parts are sometimes hard to find.

From a transparency-at-any-cost perspective, Mike wants a decent VCA-based design. From a transparency-I-can-afford perspective, Mike wants an LED/LDR-based design.

This particular analysis suggests that the Dynacomp ought not to have been as popular as it was and still is. HOWEVER, sometimes folks like the colouration that an ostensibly non-colouring device adds. Witness the Joe Meek compressors that are VERY costly, anything but transparent, and just the thing the doctor ordered for many a production. (I'd be curious as to whether the Joe Meek developers have ever considered a floor box, given that they have a few rackmount models).

9/17/1999 1:42 PM
JD Sleep	Before I make my suggestion, let me say that I think my ears seem to be a lot different from most of the others on this forum. I really like the AMZ Q&D compressor. A very simple circuit using the SSM2165 IC. It does a great job compressing and adds little or no audible distortion, which may be described by some as characterless. A Great little project though. However, if you're looking to buy and not build, I don't have much for suggestions, except that the cheap ones are usually pretty noisy if you follow them up with any other stomp boxes. I know for a fact that the DOD Stomp box compressor is a dog, however the DOD rack mount stereo gated compressor/limiter ain't bad for guitar. JD

9/17/1999 1:42 PM

JD Sleep

Before I make my suggestion, let me say that I think my ears seem to be a lot different from most of the others on this forum.

I really like the AMZ Q&D compressor. A very simple circuit using the SSM2165 IC. It does a great job compressing and adds little or no audible distortion, which may be described by some as characterless. A Great little project though. However, if you're looking to buy and not build, I don't have much for suggestions, except that the cheap ones are usually pretty noisy if you follow them up with any other stomp boxes. I know for a fact that the DOD Stomp box compressor is a dog, however the DOD rack mount stereo gated compressor/limiter ain't bad for guitar.

JD

9/17/1999 1:48 PM
Mike shaw	Thanks for the reply guys! Let me clarify what I meant by "natural" sounding. I mean little coloration of the tone of the guitar. No distortion, no pops and farts, things like that. I guess an easy way to put it is the guitar sounds the same with the compressor on or off. The only difference would be with the compressor on,it would sustain a little longer. Thanks again!! Mike

9/17/1999 4:08 PM
Jay Doyle	I own a USA made grey Ross compressor and I'd swear by it. To my ears there is no coloration of the sound, unless you set the output level to a fairly high value then you can start to overdrive the front end of your amp, but if you lay back on the level the sound is exact (except for the sustain) and it is still very warm, without pops and farts. The sustain knob is quite versitile, ranging from no effect to endless (well almost) sustain. With nothing else but the compressor on and the sustain all the way up I can get controlable feedback on clean settings (I use a strat plus through a Fender Blues DeVille). The problem is finding the little bastards. It took me 6 months to get one with out being out-bidded by some neo-hippie kid with daddy's wallet (Trey Anastasio from Phish uses one, so that is why they are becoming so hard to find, IMO) Sorry about that, I got a little worked up there. I just had about three deals for these things and then was informed that a kid had offered the seller $25 more than I did, can't blame the seller really... I've been working on a schematic to post on the net but the problem is that there is an LED/LDR unit which I can't find out the values to, if any one has any suggestions they would be much appreciated. Contrary to popular belief, the Ross (at least mine) is NOT a direct copy of a MXR DynaComp, the dynacomp does not use a LED/LDR unit. BUT the rest of the circuit is similar. Jay Doyle

9/17/1999 4:08 PM

Jay Doyle

I own a USA made grey Ross compressor and I'd swear by it. To my ears there is no coloration of the sound, unless you set the output level to a fairly high value then you can start to overdrive the front end of your amp, but if you lay back on the level the sound is exact (except for the sustain) and it is still very warm, without pops and farts. The sustain knob is quite versitile, ranging from no effect to endless (well almost) sustain. With nothing else but the compressor on and the sustain all the way up I can get controlable feedback on clean settings (I use a strat plus through a Fender Blues DeVille).

The problem is finding the little bastards. It took me 6 months to get one with out being out-bidded by some neo-hippie kid with daddy's wallet (Trey Anastasio from Phish uses one, so that is why they are becoming so hard to find, IMO) Sorry about that, I got a little worked up there. I just had about three deals for these things and then was informed that a kid had offered the seller $25 more than I did, can't blame the seller really...

I've been working on a schematic to post on the net but the problem is that there is an LED/LDR unit which I can't find out the values to, if any one has any suggestions they would be much appreciated.

Contrary to popular belief, the Ross (at least mine) is NOT a direct copy of a MXR DynaComp, the dynacomp does not use a LED/LDR unit. BUT the rest of the circuit is similar.

Jay Doyle

9/18/1999 6:48 AM
Ed	Have one in for repair, and could not find a schematic so I had to make one up, time consuming but you do what you got to do. This compressor (ROSS) compared right next to the MXR Dynacomp, sounded much better, more of a natural tone, smooth, no gas and fairly quiet, this Ross was fuller sounding than any of the others that I have heard so far, I am thinking of building a clone, I liked it so much!

9/18/1999 6:48 AM

Have one in for repair, and could not find a schematic so I had to make one up, time consuming but you do what you got to do. This compressor (ROSS) compared right next to the MXR Dynacomp, sounded much better, more of a natural tone, smooth, no gas and fairly quiet, this Ross was fuller sounding than any of the others that I have heard so far, I am thinking of building a clone, I liked it so much!

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