Ross Compressor improvements?

[mindwave_21]

Ok, so I though I would enjoy the slight treble cut from a Ross Compressor on my Heritage H-535 through to a Traynor YCV40.  In general, my 535 has a bit more treble and bite than say, a Hollowbody (I think it's the Duncan 59's), and the sound comes acrossed to my liking with a strong bass presence in my traynor.  However, when I engage my compressor, the bass becomes almost unbearably loud compared to the treble, with almost no fix when I tamber with the eq on my amp.  I want my beatiful sound back!  I love the compressor effect though, and don't want to start a new project without trying to mod this one first.  Also, I need this compressor for recording and such as it goes either DI or miked through a LDC (newly ordered MK319).  That, and I can't figure out how to use VST compressors to keep the signal from clipping, cause I have no idea how to do a lot of stuff right now.  The mid boost is fine, but the bass just overpowers the treble so much...I've tried raising the presence on my amp, lowering bass, raising mid and treble, and tampering with the sustain and level knobs on my compressor, but haven't found the sweet spot yet.  Any suggestions are welcome and thanks for all the help!

[Jay Doyle]

There is an error on some of the schematics that are going around on the web. The first cap the signal sees is NOT .0022uF, it should be 220pF. That should help with the treble cut.

If it doesn't do all that you want, you may want to try reducing the coupling caps, but I think that the first cap switch will do what you want.

Jay Doyle

[mindwave_21]

Thanks Jay, but a 220pF is already in place.  I initially even tried a 22pF ceramic, but that didn't help the pedal at all.  It was like a bypass with gated sustain...goody....However, the 220 pf I have in right now is actually a cheapo ceramic from RS.  I don't think that has anything to do with it though...or maybe it does, I'm confused...

[Eric H]

However, the 220 pf I have in right now is actually a cheapo ceramic from RS.  I don't think that has anything to do with it though...or maybe it does, I'm confused...

That's fine. You could try reducing the value of the 1uf  between Q1 and the 3080 --start with .47uf

-Eric

[Jay Doyle]

That's fine. You could try reducing the value of the 1uf  between Q1 and the 3080 --start with .47uf

-Eric

Actually you may want to try this with all of the 1 uF caps that are in there, though as you reduce them more and more you get closer and closer to a Dyna Comp.

Did you double check all of your cap values? Are you sure that you have a .001uF in place in parallel with the 150k resistor on the output of the OTA? A bigger value there would kill highs considerably.

Jay

[Eric H]

Actually you may want to try this with all of the 1 uF caps that are in there, though as you reduce them more and more you get closer and closer to a Dyna Comp.Jay

Sounds good to me

I referred to the Dyna scheme --I didn't realize the Ross had different coupling caps (other than the input).

-Eric

"I had the right to remain silent. I just didn't have the ability."  (Comedian Ron White)

[Mark Hammer]

Just about all compressors have that particular trait, unless they build in something to compensate for the lack of brightness.

The simplest fix to this is to cheat.  You will note that the MXR and Ross compressors have an output arrangement with a 10k fixed resistor in series with a 50k pot.  Try sticking a 2n2-4n7 cap between the "input" of the 10k resistor (the end closest to the .05uf cap) and the wiper of the pot.  That will provide a nice bright-bypass compensation that will give some edge to the output.  As with all such compensation, the effect is greater as you turn the volume down.  The nice thing about this is that it does not tax the chip itself.

[Jay Doyle]

I referred to the Dyna scheme --I didn't realize the Ross had different coupling caps (other than the input).

-Eric

Eric, I don't have the schems in front of me but I am almost certian that the coupling caps are the same values, it is the 1uF caps that are built into the bias supplies that I was talking about.

Those caps were put in the Ross to help prevent high frequency spike triggering and pumping that can be a problem in the Dyna.

Sorry I wasn't clearer.

Jay