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Author Topic: Preamps, tone stacks, and the TDA2003  (Read 5133 times)


  • Chipper
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Preamps, tone stacks, and the TDA2003
« on: July 17, 2007, 01:26:45 PM »
Good day folks,

I'm in the process of designing (if my random thoughts can be said to "design" anything) a TDA2003 based guitar amp. I have a couple of Ruby amps I've built, and now want something with a bit more power, and the TDA2003 seems to be a good choice from the reading and research I've done.

What I'd like to do this time around is add a tone stack to the amplifier. Can I just put the tone stack right after the input or do I need a "Fetzer valve" type setup before the tone stack? I would think that I do, as the tone stack will take out some of the tone from the input, correct?

Thanks all . . . your advice and insights are much appreciated.


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Re: Preamps, tone stacks, and the TDA2003
« Reply #1 on: July 20, 2007, 10:03:14 AM »
I've found that if im using a passive tone stack then i need a preamp of some type in front of it. I havn't tried an active tone circuit so I can't say for that.


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Re: Preamps, tone stacks, and the TDA2003
« Reply #2 on: July 22, 2007, 01:16:27 PM »
You could probably just put a tone stack in there, but I don't think it will sound that good.
First of all, you should build a preamp. The guitar signal alone is not powerful enough to push the poweramp alone, and a tone stack takes away even more of the signal. You should also use the preamp to match the guitar signals impedance to the power amps'. If you're going to just wire up a tonestack at the input, I would at least add an input and an output buffer to it,(wich again make it as complicated as the simplest preamps). You could really just add a ruby with a tone controll at the input, and run it of the same power supply as the 2003.

Thats my advice. Try the poweramp with just a simple tonestack, and then with one of your rubys, and you'll see what I mean.