I want to test the circuit before I wire the foot switch, and the method I'm using (the most common?) is to connect a battery to the board,
then the Input jack to "In" on the board, and the Output jack to "Out" on the board, grounding everything together. "In" is always clearly marked on diagrams and schematics, but what about "Out" when not connecting the footswitch?
I've come across it a couple of times, but specifically this is the one I'm working on at the moment, a v828 tone bender.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=2796&g2_serialNumber=2)
Out for the entire effect is lug 2 of the volume pot (P1-2), and the output from the board is P1-3
Hi--
R1 is listed as "10". I can see where that could be 10K (typical usually 33K), but a 10 ohm resistor there will not work and could blow Q2.
You have the schematic.
In the full-finished pedal, OUT is the wiper of P1.
The "top" of P1 would be the full-up OUT signal.
This seems to connect to both C1 and R5. And indeed the point is marked "P1-3".
R5 is a happy landmark. If we didn't have that, or the P1-3 mark, we'd know the OUT was one side of C2. But which side? The side *not* connected to R2 R3. Follow the C2 strip left, we find R2 R3, so the OUT is the *other* end of C2.
And yes, "10 Ohms" can NOT be right. 33K or 68K is fine for higher gain devices. 10K may be better for high leakage devices? It is tweakable, but it only has to be close enough to work, and would "never" be smaller than R3+R2.
Thanks for the replies
Still slow on the uptake though. ;D
To test it, I'd need the pots wired, so P1-3 would be attached, so I'm assuming I could just connect the Out test wire coming from the Mono Output Jack to that space between R5 and P1-3 connection? (Or even just straight ontop of p1-?3)
Like this:
(http://i448.photobucket.com/albums/qq202/snufkino/test_zpsece267bd.png)
Quote from: PRR on August 03, 2014, 09:31:18 PM
R5 is a happy landmark. If we didn't have that, or the P1-3 mark, we'd know the OUT was one side of C2. But which side? The side *not* connected to R2 R3. Follow the C2 strip left, we find R2 R3, so the OUT is the *other* end of C2.
So what determines C2 as being a guide to where the OUT is? Is that a general rule that Cap 2 always goes to Out?
And, yes I'm using a 10k for R1.
the R5//C2 with your green blob is fine for the output, but is at FULL volume.
in this circuit config, the output is the collector load. C2 is used to block the DC between the B- and the Q collector. dc to your amp input would/could be bad. and you don't want dc on your volume pot, because it will "crackle, not ok" when you turned it. and R5 was probably there to tell the amp-end of C2 where it was, so the voltage there wouldn't creep up with leakage and POP.
it doesn't have to be called C2, it is just that there aren't any more C's to number and 3 is taken.
Just tested it that way, and it worked fine. :)
Wired up the footswitch same way as my other +ground tone bender.... doesn't work! :icon_mad:
At least I know the problem lies in my wiring.... again.