orange squeeze + variable output, voltages?

[dachshund]

I'm building this circuit,
http://www.generalguitargadgets.com/diagrams/orangesqueezer_marks_variable.gif

Does anyone know the expected DC voltages around the 2 opamps?

thanks.

[Mark Hammer]

Not sure what you mean by "around the op-amps".  Certainly pin 5 should be sitting around 4.5v with a fresh battery, and pin 3 should be sitting a little higher than that.

[johngreene]

Not sure what you mean by "around the op-amps".  Certainly pin 5 should be sitting around 4.5v with a fresh battery, and pin 3 should be sitting a little higher than that.

Not in that schematic. Pin 5 may be connected to a voltage divider with 2 330k's but they are DC coupled to a 10k pot that goes to ground! Which probably also forward biases the diode, etc. Mistake in the schematic perhaps?

--john

[dachshund]

Yes, the voltages on the pins of the IC. So far the thing barks, at best 
This is the orange squeezer plus a second stage that Mark Hammer added.
It's possible I've got the wrong FETs. I have NTE457 which are supposed to be equivalent to the 5457... but that could be incorrect.

[Mark Hammer]

Not sure what you mean by "around the op-amps".  Certainly pin 5 should be sitting around 4.5v with a fresh battery, and pin 3 should be sitting a little higher than that.

Not in that schematic. Pin 5 may be connected to a voltage divider with 2 330k's but they are DC coupled to a 10k pot that goes to ground! Which probably also forward biases the diode, etc. Mistake in the schematic perhaps?

--john

More like a mistake in the conception, heh, heh!   I got lazy and just assumed that C6 would do all my dirty work for me.  Probably another cap should go between R13 and the R15/R16 junction, then?

[johngreene]

Not sure what you mean by "around the op-amps".  Certainly pin 5 should be sitting around 4.5v with a fresh battery, and pin 3 should be sitting a little higher than that.

Not in that schematic. Pin 5 may be connected to a voltage divider with 2 330k's but they are DC coupled to a 10k pot that goes to ground! Which probably also forward biases the diode, etc. Mistake in the schematic perhaps?

--john

More like a mistake in the conception, heh, heh!   I got lazy and just assumed that C6 would do all my dirty work for me.  Probably another cap should go between R13 and the R15/R16 junction, then?

That would do the trick.

--john

[dachshund]

Another 4.7u there?

[johngreene]

Another 4.7u there?

That should be fine, + side toward the opamp Pin5.

--john