Kryo Posted February 25, 2005 Report Share Posted February 25, 2005 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 and... 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! -Kryo Quote Link to comment Share on other sites More sharing options...
Workbench Posted February 25, 2005 Report Share Posted February 25, 2005 Try over at Aron Nelsons stompbox forum. Great knowledge and info abound!!! Chris Quote Link to comment Share on other sites More sharing options...
lovekraft Posted February 25, 2005 Report Share Posted February 25, 2005 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. Quote Link to comment Share on other sites More sharing options...
Kryo Posted February 26, 2005 Author Report Share Posted February 26, 2005 (edited) 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 Edited February 26, 2005 by Kryo Quote Link to comment Share on other sites More sharing options...
lovekraft Posted February 26, 2005 Report Share Posted February 26, 2005 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. Quote Link to comment Share on other sites More sharing options...
Kryo Posted February 27, 2005 Author Report Share Posted February 27, 2005 Ok, so I have built both the TubeReamer and the Little Gem... I quite like the tone of them both... Now, would I be able to use the Little Gem as a pre-amp for the TA8210 power amp? Quote Link to comment Share on other sites More sharing options...
hessodreamy Posted February 27, 2005 Report Share Posted February 27, 2005 Not entirely on-topic, but I was thinking of building the big muff and/or superfuzz I found on this site Uzzfay Utsgay. Has anyone tried any of these or similar? Do they work/sound good? Quote Link to comment Share on other sites More sharing options...
thedoctor Posted February 27, 2005 Report Share Posted February 27, 2005 For grins, go to www.diyguitarist.com. Guy's nuts but lotsa pedal/box ideas. Quote Link to comment Share on other sites More sharing options...
lovekraft Posted February 27, 2005 Report Share Posted February 27, 2005 DIYguitarist.com is our resident stompbox expert Paul Marossy - he should be chiming in here shortly! 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! Quote Link to comment Share on other sites More sharing options...
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