ROG Eighteen help SOLVED

[John R]

Hey there, it's me again.

I built this one https://tagboardeffects.blogspot.com/2012/12/runoffgroove-eighteen.html

I don't have any 100K trimmers so I alligator clipped 9V+ > B100K pot > Drain on each transistor. I figured I'd get them set, measure the value on each pot, and drop resistors in there.

However, I'm not getting anywhere close to 4.5V on any of the Source pins (red voltmeter lead on the pin and black on the ground, correct?)

Here's what I get on each Source with the pots fully on (no resistance):
Q1 0.28V
Q2 2.04V
Q3 0.08V

and the pots fully off (100K resistance):
Q1 0.07V
Q2 0.67V
Q3 0.01V

Last note: I put jumpers between Vol 2&3 and Tone 2&3, just so I wouldn't have to hook up pots for testing.

Thanks in advance,

John

[Ciaran Haslett]

Do you mean Drains?  Measure DC on the top leg of each FET.

again some dodgy looking cuts.  Make sure every cut is compete and free from any burrs that might short to another row/component etc.

[John R]

wow, i could swear i read somewhere on the boards here or the main site to measure from the Source. Now of course I can't find it! :)

Measured to the Drain (top leg) and got them set to 4.24, 6.8 and 4.6 with soldered-in resistors. But it's barely making a sound. Distorted, but super thin. I checked the 9V adapter, and it's putting out 11.78 Volts! I swear it was just a smidge over 9v yesterday. Can that change?

I tried it with another adapter that's putting out 9.24 volts, and it sounds basically the same. The Drains are at around 2, 5 and 2 with that one.

How is one supposed to set the voltages on these pedals when the source voltage could change depending on the adapter?

John

[John R]

I went ahead and got some trimmers, and got the voltages set to 4.36, 6.4 and 4.4 with a 9.36V wall wart.

Now there's no sound at all. No fizz, no hum, no crackle, nothing.

Here's new pix, with pot wiring...

Thanks in advance.

[ξεναγος νεκροπολης]

hi there.
i believe you've wired your input to vol3
and you give input to your circuit at the source of q1.
also i don't see a ire from master2 but i guess you use aligator clips for testing.
hope i found it!
EDIT:vol2 wire must go one hole down too

[John R]

Oh man. That was it. They should take away my soldering iron license for that one.

Eighteen and Big/Grace successfully boxed together! Rain B/G before 18, so they can be used independently, or the 18 is like a lead boost when they're both on. So cool! Gonna send those ROG guys some $$. These sound great.

Thank you so much for the help!

John