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Tubescreamer 220n, Neutrino 150n cap?

Started by add4, January 12, 2012, 10:28:55 PM

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add4

Just wondering about the 150n cap on the neutrino, right before the tone control, same place as the famous 220n of the tubescreamer, C4 in the neutrino schematic, C6 in the tubescreamer.

the 220n is supposed to give the nasal sound to the tubescreamer, but i had thought it would do that by rolling off bass. or that 220n is letting high freq signal pass to groud and keeps the bass frequencies, so i don't get how the nasal sound is produced then ..

also, in the neutrino, the cap is 150n so it should .... keep more high miss than the 220n, means there should be more high mids than in the traditional TS, is that correct?
does that makes sense?

aziltz

its actually rolling off most of the highs.  the bass has already been cut (or rather, NOT amplified by the first stage).  With the highs rolled off, the only thing left is the mids.

so yes, a lower value will leave more upper mids because the rolloff starts at a higher value

add4

thanks for your answer, i was certain i was missing something. i wasn't aware there was a high cut too in the TS. So the bass happens before that in the TS.

I guess that happens in the RC network going from the feedback loop of the first opamp to VB (C4 and R6 in bead's open source tubescreamer schematic.)?

i would have said input cap also, but isn't 47n supposed to let the whole range of the guitar through? or is it 0.47uF? :)
if that's 0.47uF, then definitely input cap.

aziltz

Quote from: add4 on January 13, 2012, 07:54:03 AM
I guess that happens in the RC network going from the feedback loop of the first opamp to VB (C4 and R6 in bead's open source tubescreamer schematic.)?

yes, most of the bass is filtered out (ie not boosted) by the opamp's RC value C4/R6