Aion lab series l5

[swtnqn]

Hi. Just finished this project and i am having problems with r76. Before it, i have audio probe and tested the 4.40 ac volts as per calibration. Right after it, audio is almost lost and ac volts drops down to few millivolts. Any clues?

[aion]

Here is a set of test voltages for each IC and transistor:

https://docs.google.com/spreadsheets/d/1GbYmJUXo2WXESJkMD1xxxkrgvPOt8DurWDE5TvscMMk/edit?usp=sharing

Can you measure yours and see how it compares? That's always the easiest first step for troubleshooting.

[swtnqn]

Thanks Kevin. Strange is that compressor is working ok. I have audio probe til one leg of r76. Then it drops to almost nothing . If i take the comp ics out...still the same.
Ic 11 3080

1    0            8   0
2    0.03       7   rail 14.83
3     0            6   0
4   -14.85      5  -14.3

Q1   d  14.83   s  2.59   g   0
Q3   -14.85   -14.14   -0.08
7815 and 7915 a little hot to the touch
Audio probe is ok on both channels and multifilter. Distortion is also ok. Compressor works as expected. Right before r76 i have 4.4 v ac 1khz. After it it drops to .030 v. Taking ic9 and 11 doesn't change anything.
Positive source on q1 looks suspicious. And 0 v on pin 6 3080 too.
Following original l5 schem...i should have almost 5v ac at both ends of r76. I have 5vac at one end....0.03 at the other one. Bad .068 cap? Bad q1?

[Paul Marossy]

I have a friend who has the real amp. Best sounding SS amp distortion ever. When I got King X's "Dog Man" album, I thought those tones were coming from a tube amp, but no it was an L5.

Anyway, hope you get that circuit working. I should try building this one just for fun.

[swtnqn]

According to the original L5 schem i should have between .5 and 2 volts dc at q1 source. So 2.6 that i have is not so strange...

[swtnqn]

Hi Paul. Yeah...i want this one working baaadly. Kevin did an amazing job on this pcb.
If you like that sound and don't want the trouble of building this project...the pearl od5 is similar...has distortion...it's highly tweakable...and kevin has a superb pcb for it...

[Paul Marossy]

Hi Paul. Yeah...i want this one working baaadly. Kevin did an amazing job on this pcb.
If you like that sound and don't want the trouble of building this project...the pearl od5 is similar...has distortion...it's highly tweakable...and kevin has a superb pcb for it...

Did you check all the usual suspects like bad solder joints, etc? Sometimes a bad solder joint somewhere or a tiny unintentional solder bridge you don't see can mess up stuff down the line.

[swtnqn]

Thank you guys for the support. The 100p cap that was suppossed to be a multilayer...was in fact an inductor. Bad supplier...

[Paul Marossy]

Thank you guys for the support. The 100p cap that was suppossed to be a multilayer...was in fact an inductor. Bad supplier...

Well that will throw a wrench into the whole system. Sounds like you got it sorted then...