Guitar amp clean stage

189

02:35:44

TL072, revision changed 270p to 220p

published 9 years ago

Karma247

9 years ago

Not working. You need to remove both the 15v supplies. The op-amps have a supply.

sturlan

9 years ago

Yeah i reversed polarity of the sources. Now its ok.

hurz

9 years ago

Inputs of second opamp have to be swapped. Keep it up.

sturlan

9 years ago

Can you please explain why? I have been reading your comments and it seems that you know a lot. :)

hurz

9 years ago

Increase the input voltage and see whats happed. The last opamp stage will act as schmitt trigger and won't come back into linear amplification again.

sturlan

9 years ago

Ok, i tested it and you were absolutely right. Please tell me one more thing: how can i know the correct gain of the TL072 opamp?

hurz

9 years ago

Std opamps do have all an open loop gain greater than 10000! TL072 i guess has even more than 100000 but this won't change your simulation a lot. Check the data sheet of TL072.

sturlan

9 years ago

I checked but didn't find. I think i don't know what to search. The number i came up with in the datasheet is 3V/V. Am i wrong or do i need to set up gain correctly to find out what is max resistance value for gain of the opamp to operate without signal distortion?

hurz

9 years ago

3V/V is as i said much to low! I guess you found the transfer bandwidth at 3MHz. That means a 1V ; 3MHz signal won't be voltage amplified any more. Above 3MHz the gain would even drop below 1 or 0dB! What i found is an open loop gain of about 200000V/V however, that does not make a big different for your simulation from EveryCircuit default gain of 100000V/V.

sturlan

9 years ago

Probably, i found that in the datasheet. OK. Thank you for all your help!

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