Re: Preamp/EQ troubles

On Tue, 25 Aug 2009 10:13:54 -0700 (PDT), jpd <jped.aru@xxxxxxxxx>
wrote:

On Aug 23, 10:34 pm, jpd <jped....@xxxxxxxxx> wrote:

I do not believe I did bypass the supply pins...  In fact I'm not
exactly sure what that means or how to do it.  15v means better
operation of the opamp right?  Sounds good, I think I'd like to do
that.

Sounds like you'd benefit from a book on opamps. Or maybe one of the
books on guitar electronics. Not to sound critical, but you're
missing some of the background stuff and terminology that will make it
easier for you to get around.

I'm using the tl082 opamp, which I figured out is rated to +-18V.

The TL082 is a bit power-hungry. The TL062 will have longer battery
life. Some compromise and go with the TL072.

The major reason for using two 9v batteries is for headroom. And you
wouldn't have to develop an artificial 'virtual ground.' Opamp
circuits need that reference point half-way between the + and -
supplies.

There's a chip from TI that could be used for that:
http://focus.ti.com/docs/prod/folders/print/tle2426.html

It looks like a small transistor (TO92 package). Effectively turns a
9v battery into +/- 4.5v by creating that 'virtual ground' halfway
between.

Could I use a voltage doubler on the 9V battery?

I wouldn't worry about that.
.

Relevant Pages

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