kylewetton
Active member
Here's the schematic, I'm wondering if any bright minds have ideas on where i should start with troubleshooting this, I've used the same ICs as recommended in the schematic
I built a GE-7 clone based on this schematic, but the volume isn't unity at 50% of volume pot, it's near unity (not quite) at 100% volume pot?
- Thread starter kylewetton
- Start date
kylewetton
Active member
I’ve left all frequencies at midpoint (they’re slide pots, all B10K). A GE-7 is meant to boost or cut the level from the center on the level pot, so I’m confused by this one is cutting the signal in half at center. This is my own PCB. I’m hoping to not modify the schematic but instead try fix what is wrong with my PCB of this schematic
kylewetton
Active member
Good point, my trace can be found in this Drive folder
GE-7 - Google Drive
drive.google.com
Enclosures are actually ported over from this Eagle library, it has 3D models included too
Dropbox
www.dropbox.com
It’s worth slightly correcting them because some are 1-2mm off center, but no biggie, I find them very helpful to confirm the build is going to fit.
What’s fun about them is that I can export the GLTF straight into Blender and make renders of them to use if I ever get around to setting up a shop. For instance this render had the PCB and all components included inside the enclosure
Brett
Well-known member
Are you seeing stable voltages at your opamps? I don't see any decoupling caps any of the opamps (except the NE5532) and your traces are suspiciously thin, especially for the power rail.
The bottom 33KΩ resistor near the top appears to be grounded on both ends, if this is R31 or R33 in the schematic you linked, your 1/2VCC bias rail isn't going to work properly.
kylewetton
Active member
Y
Also with the rails, totally fair enough, I plan to beef these up for the next version once I fix this one. I SUCK at layout so the decoupling caps are there if they’re there in the schematic, but probably not placed in a logical place. I think I may have used thin traces because I kept creating islands everywhere that lifted components off the ground pour
Youre right, that 33K isn’t connected, good eye.
Also with the rails, totally fair enough, I plan to beef these up for the next version once I fix this one. I SUCK at layout so the decoupling caps are there if they’re there in the schematic, but probably not placed in a logical place. I think I may have used thin traces because I kept creating islands everywhere that lifted components off the ground pour
kylewetton
Active member
just looking again, I just be that 33K that’s the problem, I don’t know what I did there to mess that up so bad
Robert
Reverse Engineer
I see red spokes on the left ends of both of those 33K resistors.
The right end of the top 33K goes to VCC, the right end of the bottom 33K has blue spokes which appears to be your ground plane.
It looks like you have a VREF plane (red) rather than individual traces.
The right end of the top 33K goes to VCC, the right end of the bottom 33K has blue spokes which appears to be your ground plane.
It looks like you have a VREF plane (red) rather than individual traces.
Brett
Well-known member
My mistake, you’re right. I didn’t look close enough, I just noticed the 33k didn’t have any traces and missed the colors on the thermals.
kylewetton
Active member
That’s correct, I’m away from my computer but I recall one plane is meant to be VREF, is this voltage divider even going to work with the way that 33K is connected to both planes? It almost looks like something that is technically correct to the KiCad but not actually dividing the voltage correctly
kylewetton
Active member
Because I know ya'll are having sleepness nights over this, @Robert @Brett, the final resistor in my schematic was accidentally a 1M instead of a 1K, i probed it and cross referenced my trace with the original and I found that error. Version 1.1 will have thicker traces and that fixed up. Thanks for your time on this!