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TOPIC: Alternatives to tl972

Alternatives to tl972 6 months 2 weeks ago #659

  • goku546578
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hello, I wanna say thanks for all the effort you have done with this open source and open hardware project.

I actually loved the project from the moment I first saw it, I'm trying to make a pedalshield uno and I'm buying the components and ensemble it by my own.

Unfortanetly, I can't afford buy the pack to assemble. I have already managed to buy or substitute almost all the components that I can't find, but in my town (some town in México) only are a few electronic suppliers and no one have tl972 neither lt1677 nor rc4558 (those I read that fit).

I've read that I could use a LM358 with an external power source and some diodos but I'm an IT student so I don't have enough electronic background to such action.

Could some of you guys please tell me some advices? maybe another options (without other power supplies) even though they will sound dirtier, or a way to use the LM358.

Thanks in advance guys, I really appreciate anything you can tell me.

I hope I can contribuite in the future.

See you
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Alternatives to tl972 6 months 2 weeks ago #661

  • Ray
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Hi,

The op amp requirements for pedalSHIELD UNO are just two:
- To be powered at +5V.
- To be rail-to-rail, that means that it is able to supply output voltages from 0 to 5V, because the ADC supports input voltages of 5V and it is ideal.

A nice substitution of the TL972 can be the MCP6002, in paper looks good but I have never tried it.
Other rail to tail op amp is the TLC2262.

Usually the TL972 is easy to find online, ebay, mouser, farnell, etc...

There is also this topic talking about substitutions:
electronics.stackexchange.com/questions/...art-for-tl972-op-amp

Also this forum could be interesting:
forums.overclockers.com.au/showthread.php?t=810258

The other alternative is to mod the circuit, so you feed the op amp with 9V instead of 5V but then you will need clamping diodes not to destroy the ADC because it only support 5V and not 9V.
The circuit would look similar to the pedalshield DUE (check the diodes, they will be connected to 5V instead of 3V3):
www.electrosmash.com/images/tech/pedalsh...shield-schematic.png
But you will run into another problem, finding the 1N5817 that could be difficult.
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Alternatives to tl972 6 months 2 weeks ago #663

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Thank you for your response Ray, I have already seen the stackexchange post but I did not find anything really useful.

I already found an JRC 4558D, I havent found the specific datasheet but I believe its the same as www.alldatasheet.com/datasheet-pdf/pdf/27317/TI/RC4558D.html

Do you think its a good substitute for the Tl972?
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Alternatives to tl972 6 months 2 weeks ago #664

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Hi, I am afraid to say no, the JRC4558 is a very popular bipolar dual op-amp but it is not rail to rail.
A fantastic option if you want to build a Tube Screamer but not for this....
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