Acoustic Guitar Amp KAC-60

[Woodstalker]

Hi all. I'm back after a lengthy sabbatical (previously Numpsha) and was wondering if anyone is interested in acoustic guitar amplifiers. Teemu has a nice section on these in his book which inspired me to dust off my Dean Markley KAC-60 and download the schematics. (available at Dean Markley's website http://deanmarkley.com/Info/LegacyAmps/Docs.shtml  ).  This is quite the sweet little amp (I now realize). I had picked it up for like fifty bucks at the local pawn shop to use for solo acoustic stuff at pubs around New Hampshire. Problem was, I abused it by running an overdriven Les Paul thru it and naturally the smaller speaker was not pleased. I recently repaired the amp, used it at an outdoor wedding gig in the mountains and received a lot of positive feedback from folks about the tone quality from the mike and guitar. Is anyone interested at looking at the schematics and opening a conversation about the topologies involved in this rather unique solid state amp? Anyone else have a SS amp dedicated to acoustic instruments?
Rob

[teemuk]

Is anyone interested at looking at the schematics and opening a conversation about the topologies involved in this rather unique solid state amp?

What sections especially? All circuits look pretty generic for their function.
Textbook OpAmp gain stages, generic active Baxandall tone control, BBD-based chorus with Op-Amp -based LFO and discrete lo-pass filtering to get rid of the BBD noise, integrated graphic EQ chip, basic reverb and FX loop amps, and a generic differential input power amp. About everything else but the bucket brigade delay chorus is discussed in my book. Even that will be featured in the next edition.

Basically that chorus is just a bucket brigade delay controlled by a LFO. The actual BBD is the IC8 while the IC9 is a driver for it. Q1, Q2 and the surrounding components are filtering to remove the switching noise and distortion BBD chips create.

[Woodstalker]

Thanks Teemu!

  Great snapshot circuit analysis  ..  I was a little overwhelmed by the power amp section and also was curious how (or if) the amp was designed to reproduce a wider frequency range than a "normal" guitar amp. I was thinking that perhaps the filtering in different stages may be a factor in its voicing  ..  I'm just not quick enough to grasp this stuff at first glance. But, no excuse  ...  the resources are within arm's reach. 8|