Pre-Amp, Fancy Chip?

[petemoore]

http://www.electronickits.com/kit/complete/ampl/k100.pdf
 This pre-amp tone control looks pretty easy to handle build wise.
 In an application like Driving a Tube power amp Dyna ST70...with Stompboxes before it...
 Any suggestions as to a good one or whether somehting like this might be cool for my needs are welcomed...!

[Fret Wire]

That was in the link I threw up for the amp thread. I checked out the preamp too. Looked like it might make a nice companion for the 18w (5watts RMS into 8 ohms) mono amp.

http://www.electronickits.com/kit/complete/ampl/ck706.htm

http://www.electronickits.com/kit/complete/complete.htm

What threw me though, was the balance pot. Seems like it could be converted to a midrange or presence control. But would the pcb support that?

[Peter Snowberg]

Hehehe.... I built a digitizer in the late 80s that used a TDA1524 for front-end filtering. It was modeled after somebody else’s design that used the same chip (does anybody remember an Apple //gs board from a company called MDIdeas called the DigitizerPro?). It's an interesting device.... I just wish you could get separate control for bass and treble on each side. Oh well...

It's a serious power hog, but it works. I think you're better off with building your own filters in the long run.

If you want an interesting effect, connect two LFOs to the bass and treble inputs.

You can also get wahish noises by connecting an inverting opamp stage between the bass and treble inputs.

The balance control is an extension of the volume input. I would just tie it to 1/2 of the control voltage supply and leave it although I guess you could use it as a pseudo mid control in a weird sort of way. One thing to think about would be to use different caps for the left and right channels and run them in parallel with a summing amp at the output. that would make the balance control useful for some additional tone control.

Take care,
-Peter

[Ge_Whiz]

But would the pcb support that?

Heh, heh - if you know what you're doing, and have a decent craft knife, most PCBs can support almost anything... :twisted:

[Mark Hammer]

The bass/treble turnover frequencies for that chip appear to be optimized for music reproduction (i.e., full band/orchestra recordings) and are fixed internally.  You will note from the kit schematic that the controls simply provide a control voltage to the chip, which takes care of everything else.

Unlikely to be a useful chip for guitar because you can't revoice the tone stack at all.