It looks like the general "D" style effects loop is right off the master volume between the pre-amp and the PI. I have a circuit that's similar to an AB763 with an added D'style OD circuit and I've put in a Lar-mar style post PI master volume. So in something like that if I want an effects loop (preamp out power amp in) where would I do that? Would it just go in-between the end of the pre-amp section and before the PI still?
(I don't have the schematics handy...I can post those later, sorry...just can't stop thinking about this while I'm at work
Humbly,
mark.
"...there are flying v's and then there are the ones shaped like peanuts..." - my son at age 9
Big problem with effects loops is where to put them, and signal levels involved.
between preamp out and power amp in is already difficult, because signal level there is usually around 1 V RMS and sometimes up to 4 V RMS ,a tough act for any effect to follow and definitely impossible for a 9V powered one.
And practically impossible after the PI, because signal levels there run into the 20 to 60V RMS area ... who can cope with that?
And to boot you have two, balanced, out of phase signals.
Better swallow the whole pill, no matter how large and bitter it is, let the power stage clip, let it drive some kind of load, attenuate to effects loop levels, process and reamplify.
The only loop I use anymore is a virtual earth mixer with the dry signal at unity and the wet signal at whatever you need. You need two triodes, so space for an extra 12A?7. KO'C has examples in a couple of the books.
Would it just go in-between the end of the pre-amp section and before the PI still?
That is how I have done it and it has worked fine with me. This is just one schematic of several amps where this has worked successfully for me. I have NOT found the PPIMV makes any difference with the "normal" D-style topology of FX insertion.
My favorite amp that I am currently playing has a PPIMV and the FX there.
with respect, 10thtx
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