GGG bmp violet rams head

[Devius]

All my values seem to be correct. It sounds amazing... when the volume knob is cranked. The same problem that plagues my Starscreamer also infects my muff. With the volume knob on full, its unity gain. I used the ggg violet rams head schematic, my own layout, the only substitution is in the tone stack (I used a 4n7 cap instead of a 3n9).
I love the sound, I put on a tone bypass switch, it is doing what it should.
The sound is great with the vol pot full cw but even when I roll it back to half it is barely audible.
Anyone have any ideas?

http://www.generalguitargadgets.com/pdf/ggg_bmp_vram_sc.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

[Govmnt_Lacky]

Check the way you wired the Volume pot to the PCB. Make sure you don't have the wiring reversed.

[pappasmurfsharem]

Assuming you used a LOG pot as per the schematic. You could try a Linear are Anti-Log pot and see if the control suits you better

[Devius]

The volume pot is wired correctly, lug 1 to ground lug 2 output and lug 3 from c13.
I'm just frustrated that this effect is not louder. I'd like unity gain to be around noon or so, not full cw.

[Govmnt_Lacky]

As far as I know, BMP circuits should have PLENTY of gain on tap. Far beyond unity.

You need to look deeper. Look at the debug thread and post voltages.

[Devius]

All the voltages are spot on. Super close to the reference voltages from ggg. I measured from the collector on q4 and its 4.56v up to the output cap, after the output cap is 1.10v which is what is coming from the output.
Should this not be 4.56 or close to it?

[lowbrow]

This sounds like a job for a audio probe.

[Arcane Analog]

Do you have the correct value for the volume pot? Wiring it in reverse and/or using a different taper will not change maximum volume output - it will just make the sweep work/feel different. However, a different (lower) value pot will definitely change the amount of output available.

[LucifersTrip]

The vol should indeed be way over unity.

It's a very easy circuit to debug since it's nothing more than 4 linear stages.

Just take an output after each of the stages and see where you're vol drop is, starting with the cap after the last transistor before the vol pot and work backwards.

But first, look for problems with your input and output jack wiring and connections. A crap connection/crap quality jack can actually cause a low volume.