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Hoffman Amps Forum image Author Topic: wanting to use an op-amp reverb circuit/power supply question  (Read 1968 times)

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Offline phsyconoodler

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I want to add an op-amp reverb circuit to an existing amp that has no room for tube sockets .Is it best to add a transformer for the op-amp power supply or is it ok to use a rectified ac power source?I want to utilize a blues jr design that requires a 5v power supply for the op-amp.Having not done this before,I kinda would like to not stress the PT if it can't take it.I can't see an op-amp drawing very much current but I may be wrong.
  Anyone done this successfully?

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Offline HotBluePlates

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Re: wanting to use an op-amp reverb circuit/power supply question
« Reply #1 on: April 06, 2014, 09:10:40 am »
... I want to utilize a blues jr design that requires a 5v power supply for the op-amp. ...


Are you planning on using the same opamps that the Blues Junior used? If so, a +/-15v supply was used, derived from a ~20vac winding.


Looking at that schematic, it appears there is ~16mA is drawn from each leg of the +/-15v supply, based on the voltage drop across R50 & R53. If you have the needed winding, I bet you know if you can spare 16mA.

Offline eleventeen

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Re: wanting to use an op-amp reverb circuit/power supply question
« Reply #2 on: April 06, 2014, 03:20:28 pm »
A tube power transformer will not even know an op-amp is there. The current draw is tiny.

 


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