Ross Compressor Too Bright!

[erick4x4]

So I know that the Ross Compressor is usually described as one that has a noticable reduction in highs, so that is why I think mine is funny?

It works right, it compresses like its supposed to, but when its on, no matter at the max or min compression, it still brightens my tone (or maybe just cuts some lows). I have checked all the parts and they seem to be right. I don't have another op-amp to try, could that be it? Or where should I be looking to fix this?

Thanks for any help.

[Shakal]

 What is your base layout?

I just made a Ross Comp using the Tonepad's layout, and it didn't bright anything, actually it "mudded"(a term I learned here) the tone but was a wrong Cap.

Maybe u got a wrong cap too.

[Murfman]

Shakal-

I just finished a Ross compressor and it too is way too muddy with far too much loss in the highs. Which cap did you change out and to what value?

Any help would be appreciated.

Thanks-
-Murfman

[nordine]

the ROss/DYna compressors, more than loss of highs or extra highs, they both cut bass and highs, thats why some find their sound "mud up" (take in count also that 'too bright' can mean little bass content)

two changes can bring back the missing frequencies (following tonepad's layout):

-for highs restoration:  .001 cap on Q2 base. Make that a 470pf and you'll get your highs back (turn it up, like .0022, and that will cut excessive highs)
-for bass restoration: output cap is .05. Change that one to a 1uF, then the bass is restored

cheers

[Mark Hammer]

Important to distinguish between what the compressor does to the tone as a function of favouring certain frequencies even when the compression is not up very high, and what it does to the perceived tonal balance as a function of evening out levels of different parts of the input signal when the compression is set for greater squish.

before you start performing surgery, it might be best to set the unit for less squish and do some critical listening to determine whether the cause of your undesirable tone is cause #1, cause #2, or some particular combination.

[JDoyle]

You have an error in the value of one of your coupling caps.

Recheck all cap values, make sure all bias resistors are the correct value (i.e. make sure the two 470ks on the input Q are actually 470k, not 47k) and double-check the cap and resistor values of the filter network on the positive input of the 3080.

As a general rule:

IF YOU BUILT IT ACCORDING TO A VERIFIED SCHEMATIC AND LAYOUT (and the input cap to ground is 220 pF, NOT .0022uF) AND:

Your circuit compresses but the output TONE is the problem, there is a part value error somewhere OR if it is not extreme and subtle, you need to tweak the cap values to adjust the tone (don't mess with the resistors so much, unless you know what you are doing).

Your circuit is DISTORTED, it is a bias problem with one of the semiconductors (most likely the 3080 as long as the Vbias string is definitely 56k/27k). With everything connected from guitar to amp, turn the trim until you hear the MOST noise. Don't use two 1k resistors - the offset adjustment happens over about 60mV and two 1k carbon comp resistors could put the offset outside of this on tolerance variation alone. Use a 2k trim for the best results.

Regards,

Jay Doyle

[Murfman]

I'm going to try the 0.001 to 470 cap change. I've checked and double checked all components and values before I posted. They're correct. Although, I used lots of parts that I had instead of buying better caps. All my polar electro caps are 50 volt Xicons with 20% tolerances. Not the greatest by any leap. I'm not sure how much these shape the actual tone of the pedal. The pedal is quiet with zero hum.

Would it be worth it to change these out to better caps?

Which caps should I focus on when it comes to the actual tone in this pedal.

I wanted to also say that this forum is an incredible resource to newbie builders like me. I've learned lots and have been inspired by you guys. Thanks for your help and patience with the dumb questions! I do try and search and read past posts before posting the same question for the hundredth time (I know you guys must get tired of this) And have answered most of my questions and troubledshot most bugs this way.

Again, thanks for your help and knowledge.

-Steve