adding vu meter to output of pedal

[randomair]

hey all, i was wondering if anyone could school me on adding a vu meter to the output of a shaka tube TL072 version? can i just tap into the master volume pot and bring the other lead on the vu meter to ground? or maybe the output pin of the tube? thanks!



here is schematic for the pedal i have built:

http://www.diyguitarist.com/PDF_Files/ST1590BB-PCB_9-9-06.pdf

[Mark Hammer]

Do you want an old-school electromechanical VU meter, or is an LED meter sufficient?

[randomair]

i have a number of old school meters in my shop...i like the needle movement. so yes, the electromechanical meter is my flavor of choice.thanks for your response!

[randomair]

still curious to know if anyone has an idea of how i can accomplish this? thanks again!

[R.G.]

still curious to know if anyone has an idea of how i can accomplish this? thanks again!

The problem is not whether there is any idea, it's sorting one out.

The simplest is probably to put in an LM386 power amp chip to drive the meter then to dink with the signal level in and and gain in the chip to get 0db whereever you think it should be on the meter. Guitar does not normally reach 0DBm, so you'll need some conversion.

[Steve Conner]

See Figure 1 in this page.

http://sound.westhost.com/project55.htm

Drive it from an op-amp voltage-to-current converter to get round the diode forward voltage thing. Note that some VU meters may have the circuit of Fig.1 inside already.

[frankjc]

I don't know the answer to your question, but that looks like an interesting pedal. How do you like it?