MightySmallElectrons
Active member
I’m getting ready to build my 3rd Muroidea pedal and am curious if you have a mod that you think makes this classic even better and why?
There are two 4.7uF caps. Are you talking about C2 or C7?I usually lower the 4.7uf cap down to 1uf to get rid of the farty compression sound but other than that I love them stock or Turbo spec.
What’s your preferred value for C8?There are two 4.7uF caps. Are you talking about C2 or C7?
I like the BASS mod and increasing C8 so the entire range of the FILTER control is usable.
There are two 4.7uF caps. Are you talking about C2 or C7?
I like the BASS mod and increasing C8 so the entire range of the FILTER control is usable.
What’s your preferred value for C8?
What is the ‘BASS mod’ ... I’m guessing it’s in addition / complementary to increasing C8?There are two 4.7uF caps. Are you talking about C2 or C7?
I like the BASS mod and increasing C8 so the entire range of the FILTER control is usable.
https://forum.pedalpcb.com/threads/so-this-is-where-i-am-with-my-pandora.1601/#post-11782What is the ‘BASS mod’ ... I’m guessing it’s in addition / complementary to increasing C8?
I've just modelled the Rat in LTSpice to learn about the circuit before I build it. I noticed that the distortion pot seems way too big as you are clipping the op amp before you get close to half travel even on a 100k log pot (~10k). So I think you are right. Of course the diodes then clip again..... I also like a lower value gain pot but suspect I might be alone on that. I have no use for crazy amounts of dirt except in a gatey fuzz.
With the 2N5457 (don't have the -58 model) the drain current is 45uA-165uA, and with the J201 it falls to 15uA-130uA. So, not zero but close.The Rat has two tone ranges: opamp clipping and diode clipping. Some people only like the latter and in that case, limiting the max gain is a good idea. Referring to the Muroidea schematic, the max gain can be reduced by either reducing the DIST pot or by increasing the impedances of C2, C3, R3 & R5. If you reduce the DIST pot, you might want to increase C5.
The J201's Vp is too low for the output buffer unless you bias the gate up. There are plenty of JFETs that are good subs for 2N5458 in the Rat. J201 is not one of them. Look at Q1's drain current waveform in LTSpice. Does it go to zero during part of the waveform?
I recently built a stock rat and think this might be what I am experiencing/want to look intoI usually lower the 4.7uf cap down to 1uf to get rid of the farty compression sound but other than that I love them stock or Turbo spec.