Bit Commander Debug (This may get complicated)

[Kevin Mitchell]

There isn't much for help out there reguarding new/unfamiliar effects and layouts. So please work with me here.

I've been meaning to design a pcb for the bit commander that has been floating around recently. The other night I've found this layout and decided to give it a go seeing how it's said to be verified. Upon firing it up and playing around for a bit I realize that the low octave is nowhere in the signal. After spending hours poking around attempting to debug I feel I should seek some help.

I've drawn the schematic from another layout a while back and compared the recent layout I've used and they match up. So I'm sure it's good to go. I'd share it for debugging efforts but due to the effect being somewhat new I suppose that would be frowned upon (probably why I can't find one anywhere)

On this site where the pcb is presented I beleive they've mistakenly said the CD4024BE and transformer works at the high octave and the dual opamp is for low. From what I can guess the high octave is from the transformer and the low is from the 4024 and then is mixed through the TL072. So the JCR386D (audio amp) is for input/effect? I'm no expert these are simply my thoughts.

So here's what's going on. To note, I'm using a TM022 transformer and at the moment have omitted the protective diode and cap. The Octave up, Base, Level and Filter seem to act. But I don't think they work fully with the octave down effect missing and all. The Octave Down and Sub don't seem to do anything. My first thought was to check out the 4024 that those 2 controls feed from. I only have one so I can't swap it out right now. The traces seem to be fine so my next guess would be a problem with what's going on with the opamps. No cigar from my efforts.

All settings half way (all linear pots) All NC-not connected read 0v.
CD4024BE
1-8.42    2-0(gnd)    3,4,5,6-NC    7-0(gnd)    8,9,10-NC    11- 9.28    12-9.28    13-NC    14-9.32(v+)

TL062 (Tried TL072 and LM358 with same audio results)
1-4.64    2-4.66    3-4.63   4-0(gnd)   5-4.63    6-4.66    7-4.66    8-9.3(v+)

JCR386D
1-1.31    2-NC    3-0   4-0(gnd)    5-4.59    6-9.31(v+)    7-NC    8-1.32


These voltages should be correct I apologize for any mistakes. Please let me know if you notice anything I should check out. Any possible solder mistakes have been investigated with no luck and I'm sure it's not a wiring mistake. If you would like a copy of my notes(the schematic) please let me know I could share a temporary link.

Waiting for the regrettable (simple mistake) face-palm moment. Any help would be greatly appreciated.

[slacker]

Something's wrong around pin 1 of the CD4024, it shouldn't have any DC voltage on it. Maybe it's shorted to pin 14? Double check against the layout that you've got everything correct between the output of the 386 and pin1 of the 4024.

[Kevin Mitchell]

You're the man slacker! 

Spot on. There was the smallest short at the 4024 pin1/100k and the v+/4k7(led res). I didn't think it was linked to v+ with it being about 1 volt under. Now I hear it. There's allot of variation between the controls and dialling it to something desirable or workable is difficult. I'm thinking using a TM022 instead of a TM011 may have diminished some of the high octave sound - it's not as pronounce as some demos. I'll keep at it. It has a while before being boxed.

Gotta play around a bit more perhaps I'll post a sound demo later.

[thehallofshields]

Do you have all 6 pots mounted on your board?

[Kevin Mitchell]

Do you have all 6 pots mounted on your board?

That's a silly question. If you check out the pcb I used (link in top post) you can tell that it isn't for board mounted pots.

I am however using board mounted pots for the first time for this project ironically. I'm designing daughter boards for the pots and my custom bypass system. At the moment the controls are breadboarded.

[zsound]

Hi, i would like to know where i find the  component list of the bit commander? (capacitor type) Thanks