Flat mids & notch filters in a screamer clone circuit...

[SteveB]

I know that there are a few sites with explanations of how to lessen the mid range peaks in tube screamer style circuits. Most involve lowering capacitor values, which do indeed give a better bass response to my ears, while also making the mids seem less prevalent. GEO & John Greene's site were really helpful on this.

I built one using these things found on the web, & while I think it sounds very good to me, it is still a bit more midrangey than a FD 2, & lacks a bit of the sparkle I hear in the FD2. It is subtle, & most noticable when A/B-ing both pedals while playing the same lick or phrase.

Looking at the guts of the FD2, there are obviously more parts than in the one I built, namely more capacitors & resistors. While most of them are identifiable as being just like an original TS circuit, there are others that make me wonder what their purposes are. Like a small value ceramic cap near the input, & a .005 film cap elsewhere on the board, not to mention some additional or different value electrolytics & resistors. This FD is for a good friend, & I don't want to cut all that silicone out to take the circuit board out to try & trace some of these.

Could there possibly be some sort of notch filtering going on in there?

Thanks,
Steve

[cd]

The cap on the input is for RF rejection.  The extra electrolytics are probably for power supply filtering.  In general, play with the values of the tone caps (.22u caps on the tone control) for more/less mids.  For more high end sparkle, try a larger value Volume pot (1M) and/or get rid of the small value cap in the first stage feedback loop.  Or put a cap across the volume pot like a bright switch.

Can you take pictures of the top/back of the board?

[SteveB]

Pictures of mine, or the FD2? If it's the FD2, like I said in my post, I can't take the FD2 circuit board out because it's not mine, it's for a friend. I can take photos of the component side.

Steve