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Hi peeps...

I have aquired several op-amp IC's and am having a problem choosing what to build with them...

I have...

1 LM324N Quad Op's

1 LM358N Dual Op's

1 LM386N Single Op

2 TA8210AH 20w Dual Channel Power amps


2 TL071CN J-FET Single Op's

Can anyone recommend a decent sounding pedal that uses any of these chips?

I have already built a SmashDrive with the 386, but I wasn't that impressed with it... I would prefare not to mess around with J-Fet's or other transistors (Unless they are generic)...

Any help would be much appreciated!


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Run over to Runoff groove and get the specs on the Tube Reamer - that'll take care of one of the TL071s. While you're there, look at the Little Gem - a good use for that LM386 (which isn't an op amp, it's a power amp).

That TA8210 chip is also a power amp - the datasheet is here. It's pretty simple to use, but you're going to have to build a hefty power supply to feed it. Those Toshiba chip amps are used in a lot of low-end guitar amps - you could easily make a nice amp with the right preamp design.

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Thanks for that!

Assuming I was to build an amp with the TA8210 chips, would this be the circuit to reproduce?


Obviously the red highlighted bits are the output, but I don't understand what to do with them...

Also, the blue highlighted bits... are they needed? if so how would I implement them?

and by adding a LOG/LIN pot to the output would act as a volume control?

I'm not a n00b at electronics... just a n00b with amps and IC's :D

Edited by Kryo
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The load resistors are your speakers. The blue bits are respectively a preamp mute switch and an amp standby switch - they'll probably have to be biased as shown to make the amp drive the load(s). Any volume adjustment or tone shaping should be done before the inputs (in a separate preamp). Putting a 20 watt rheostat on each output doesn't work very well, and could easily cause heating problems and chip death. And remember, it's designed to drive a 4 ohm load with each channel.

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DIYguitarist.com is our resident stompbox expert Paul Marossy - he should be chiming in here shortly! :D

Kryo, you shouldn't need anything as hot as the Little Gem (remember, it's a power amp, not a preamp) to push that Toshiba chip - it looks like any preamp with about 20dB of gain will drive it to full power. A dual opamp with a Baxendall tone control would probably be the simplest approach.

hessodreamy, you owe it to yourself to build at least one Big Muff PI in your lifetime - you may hate it sfter the novelty wears thin, but I promise you'll recognize the sound(s) it makes! It's my favorite old school squonk box! URock.gif

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