QUOTE
i have another question.what values should be used for the pots?is there any difference in sound quality if the whole circuit is designed for 500k pots instead of 10k pots?
........imho lower pot res is preferred........have a look at this thread
http://www.diyaudio.com/forums/chip-amps/176182-problem-ne5532-based-preamp-3.html
greets
i have another question.what values should be used for the pots?is there any difference in sound quality if the whole circuit is designed for 500k pots instead of 10k pots?
........imho lower pot res is preferred........have a look at this thread
http://www.diyaudio.com/forums/chip-amps/176182-problem-ne5532-based-preamp-3.html
greets
Hey Godfrey,
Thanks for thinking things through and pointing out my doodoo - because that's precisely what it was, I made a mistake when cobbling together the schematic (redrawn from another source which didn't have anything to do with guitars)
I was concerned whether corner frequencies of both sections make sense for guitar duty.
Good point, I'll definitely have to make sure there is enough gain left over. As it stands now, with a very conservative estimate of the openloop gain (this is a tube amplifier, hence no schematic in this part of the forum ) there should be 20 dB to spare if guitar pickup puts out 0.06 V RMS max. (anything more than that and the output will overdrive). I believe this to be a reasonable assumption, plus OL gain is likely to exceed the conservative estimate so some GNFB will be needed anyhow.
Thanks for thinking things through and pointing out my doodoo - because that's precisely what it was, I made a mistake when cobbling together the schematic (redrawn from another source which didn't have anything to do with guitars)
I was concerned whether corner frequencies of both sections make sense for guitar duty.Good point, I'll definitely have to make sure there is enough gain left over. As it stands now, with a very conservative estimate of the openloop gain (this is a tube amplifier, hence no schematic in this part of the forum
) there should be 20 dB to spare if guitar pickup puts out 0.06 V RMS max. (anything more than that and the output will overdrive). I believe this to be a reasonable assumption, plus OL gain is likely to exceed the conservative estimate so some GNFB will be needed anyhow.sorry.i forgot these caps in the schematic.but in the layout i have included only 100nf decoupling capacitors at both opamps rails.i thinkk i have to make a new layout to include electolytics too.
i have used a tl072 as an input buffer and not opa2134 because i have only one opa2134.the layout is stereo.
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