Mini zen problems

[baggystevo82]

Hello, I've been building Marcello Pellerano's Mini Zen headphone amp and have a problem. The voltage drop accross r10 and r12 is constantly 40mV exactly, on both channels, no matter what the adjustment pots are set to. The schematic is here and I was hoping one of you might know what I'm doing wrong.
Cheers for any help,
Steve

[wuffwaff]

Hi Steve,

40mV means that (almost) no current is going through the fets. Please check your active current source (especially the voltages across the transistor). Something is surely wrong here. Since it is in both channels it won´t be a bad solder contact but must be a systematical mistake. Like a wrong connection or a restistor (2k2 instead of 2R2..........)

William

P.S. Your Ultima?

[baggystevo82]

Hi William,
Yeh I thought I must have done something stupid for that to happen. It doesn't sound too horrible though, just very lacking in power at the moment, but then I haven't had much to compare with.
I'll have a good check through the schematic and my layout later tonight.
P.S. One day!
Cheers,
Steve

PPS its more likely to be a wrong connection rather than a wrong value component isnt it? As the drop across r10 and r12 doesn't change at all.

[baggystevo82]

Fixed! Dozy me put the drain connection to Q1 the wrong end of R1 spose that'll teach me for building it at 5am last night.
Finished now anyway, so here it is...
Cheers
Steve

[baggystevo82]

Hello, finally got some reasonable pictures of it. Please let me know what you think, and your experiences with this amp design.
Thanks,
Steve
PS temporary case!!