OPA549 on single supply

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Hello !

Can anybody comment if the schematic for connecting the OPA549 on the single supply is correct ? If it is not please give me some advice how to make it right.

Cheers
 

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There's a few errors, look at your power supply connections. But more importantly why would you want to run with a single rail? You now have to use a coupling cap at both the input and output which isn't what I'd recommend for anything related to hifi. If you only have a 30-volts single rail you can also split it to 2x15 and settle on that.

Best regards,

Sander Sassen
http://www.hardwareanalysis.com
 
Hi bostjancek,

Yes, there are a few errors on your shematic.
The 4,700uf + 100nf caps are in series with the positive voltage rail (?!), they should be parallel from V+ to ground.
The input 2.2uf cap should be before the 47k cap.
And a suggestion: use a 4,700uf cap on the output, although not so important for a guitar amp.
 
carlosfm said:
Hi bostjancek,

Yes, there are a few errors on your shematic.
The 4,700uf + 100nf caps are in series with the positive voltage rail (?!), they should be parallel from V+ to ground.
The input 2.2uf cap should be before the 47k cap.
And a suggestion: use a 4,700uf cap on the output, although not so important for a guitar amp.


And... use a snuberized PSU :D ... I like the snubber that sound is more beautiful than the others schematics! I love your idea.

Thanks :bawling:
 
bostjancek said:

Can anybody comment if the schematic for connecting the OPA549 on the single supply is correct ? If it is not please give me some advice how to make it right.


One suggestion:

Try a different way for your virtual ground input connection. Increase the value of those resistors to something like 47K each, and don't connect that point directly to the + input, but through another 47K resistor. Then use a a 1uF capacitor from that middle resistor point to the V- rail. That should lower your ripple noise. Or use the parts used in the LM3886 datasheet for single supply application.

A single supply design has several flaws, the large output capacitor being the main one. So I don't think it will help much using a snubberized supply with it.


Carlos
 
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