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Ross Compressor Fuzz Central Mods to guitarpcb MoRC

Started by claytushaywood, May 18, 2012, 01:23:45 PM

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claytushaywood

I have a guitarpcb.com MoRC which is basically a modified ross compressor.  It has some of the fuzz central mods done to it, but they are a bit different.  I am not getting the amount of treble response I'd like out of this pedal, the keeley comp had a much better treble response... it even added a nice amount of shimmer in my experience.  I actually noticed that the Ross and the Keeley both used tanatulum caps for all the electrolytics- and I tried them out for the heck of it, even though a LOT of people have said it wouldnt make a difference- it totally did improve the high end response of the pedal, and seemed to make the recovery 'quicker' or something- a nice improvement in the feel.

Anyways- the fuzz central mods say to change the 220pf input cap to ground to 100pf to reduce the amount of treble frequencies gone to ground.  The MoRC eliminates this cap completely.  That means the MoRC should have more treble content and possibly more noise, right?  Would adding the 100pf cap take away more high end?  would it help with noise?

Another fuzz central mod to the original ross is to add a small capacitor in parallel with the 10k resistor going to the level pot (or output)- the fuzz central says to use 1nf, the MoRC has a 2n2 cap there- would 1nf allow more treble or less than the 2n2?

I was also contemplating trying out one of those old school metal can RCA 3080's.  Has anyone tried this?  I've heard it is a nice improvement over the modern ones?  Also, I believe I read they used a different one in the 80's or something that was supposedly an improvement over the original. 

Does anyone know what the secret to the keeley comp is?  Or what I should do to get that kind of transparency?  I was also digging the mix control on the barber tone press... anyone have any info on how to add that control?  I also dig the attack knob on the keeley 4 knob... etc etc... etc... haha.  Should I just build the BYOC 5 knob?

Any help or direction is much appreciated!

claytushaywood

well... I didnt get any replies to this... so i just did it without knowing the outcome.  and I am VERY impressed.

definitely do the fuzz central mods if you build a ross clone.  I also completely eliminated the small cap to gground on the input (well it was never there to begin with as in guitarpcb's morc board) Would adding this cap give me even more treble?

I think tanatulum caps play a big part in getting a "faster" responding compressor, along with a kinda of quicker and more present treble response... call me crazy, but try it for yourself... there's a reason all those comp pedals use em... i think. 

the cap in parallel with the 10k resistor near the output is crucial- and the switchable recovery mod is cool.
I did the 10uf cap coming off Q5 at the same time, so i'm not sure of it's exact implications but the pedal does seem to have less noise now. 

These things changed this compressor, from completely muffled and poopy, to awesome and on my board!  as far as I can tell, each mod was important to getting closer to the keeley comp pedal (which I like). 

I could still use a LITTLE bit more treble though and I would love to add a controllable attack and a blend knob.  Anyone point me in the right direction?