SOLVED First vero build - circuit works but output is barely audible.

[zakco]

My first Vero build. It’s the Mind Bender as per this layout:

Mindbender Fuzz - Compact layout

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tagboardeffects.blogspot.com

The only modification is the trimpot is wired off-board to a regular pot

Voltages at all transistors are good, all controls function as expected but the output is barely audible - probably 30db quieter than it should be, but I can clearly hear that other than the output level, the volume, attack and bias pots are working. The gigantic GT404s make it difficult to see the top layout, but I've taken photos from a few angles, so hopefully everything is visible.

Any help would be appreciated, thanks!

 

[zakco]

Can you bias it out with the trimmer?

was it this gated when you breadboarded the circuit? (with the exact same transistors, in the same positions, i presume).

This vero layout doesn't have a trimmer on Q1, so I have removed the transistors and rebuilt the circuit on a breadboard using this schematic: https://generalguitargadgets.com/pdf/ggg_tb_m2p_sc_ng.pdf

Q3c biased to almost exactly 8v with a fixed 15k resistor and with a trimmer on Q1c, I balanced Q1 to 8v with a fixed 8k2 resistor and now the circuit sounds glorious. A nice wide range on the Attack pot with no unwanted gating. It sounds so good, I might just skip the bias pot altogether when I put it back on vero. Fingers crossed I don't screw it up again!

EDIT: I messed around a bit more with the bias and I actually prefer the sound with Q1c and Q3c both at 8.4v . It sounds pretty much the same at higher gain settings, but it's sweeter and more controlled when the Attack control is turned way down.

 

[Coda]

EDIT: Yes, you are absolutely right. I read the outline of the trimmer as a connection. I re-soldered the output cap to the correct junction at it works! Well done...thank you! And boy do I feel dumb...sheesh.

How can you feel dumb after learning something? You should feel anti-dumb now. You are stronger as a result of your new knowledge…

 

[zakco]

Well, I'm pleased to report that I spent a bit more time fine tuning the bias, put the circuit back on Vero and it sounds amazing! Thanks to everyone for the help and encouragement. I was definitely ready to give up after my 2nd failure