AION Comet DS1 - sound is a low fuzz

[broomhandle]

Hello Everybody,

I have built a Lion DS-1. I chose the vintage build. I get sound when engaged. Volume and tone work. The distortion knob does nothing. It sounds like a low "tone turned down" fuzz. Pictures attached.

any help?

[antonis]

Check continuity between DIST pot lug 3 -> R10(47k) -> C7 (1μF) -> GND

If something there is "open", IC1A acts as a buffer (unity gain) so the only distortion comes from Q2 preceding stage..

[iainpunk]

i suggest you lookt at this link:debugging guide

cheers, Iain

[broomhandle]

Thank you, I am testing now. Trying to figure it out...

[broomhandle]

Hello,

thanks for helping. When we are talking Left and Right, I think we are talking about from looking at the top.

My results are odd (Left and Right) I am not the best with a DMM... here are my results.

1.) DMM on cont. red prob on dist lug 3, black probe on R10 right leg.  = no beep on right leg ( - ), but beep on left ( + )  (looking from top down)
2.) DMM on resistance. black prob on dist lug 3, red on R3 =   I get no reading.
3.) DMM on cont. black prob on dist lug 3, reg prob C7 = no beep on either leg.
4.) DMM on cont. Red prob on C7, black on ground. = beep on ( - ) right leg. no beep from left leg (+)

[antonis]

I might confused you about Left-Right, so here it is:

[broomhandle]

I think I am more confused now.

so for C7, are you saying left leg as in (+) or (-)

and for 1-3. the red prob should be on lug 3 of dist pot?

I think this is right... photo attached...

sorry if I am more confused now.

[antonis]

Forget about DMM probe polarity, either for continuity test or resistance measurement..
(you don't read your P.M.s thoroughly..)

C7 Left leg should be the one marked (-)

As for R10, place one probe to pot lug 3 and the other probe to one of R10 legs..
You have two options:
1. Beep -> OK
2. No beep -> turn to resistance measurement mode -> 47k -> OK (no need for other leg beeping now..)

[broomhandle]

Ok..

1.) LUG 3 > R10 = a beep on the left side. "Picture attached". If that is not correct. I can do this:

No beep -> turn to resistance measurement mode -> 47k -> OK (no need for other leg beeping now..)

2.) Lug 3 > C7 Right (+) = No Beep
3.) C7 Left (-) > Ground = Beep

Sorry if any confusion. I am a novice. I just thought this is fun, until one has issues.. thank you again everybody for helping.

[antonis]

OK..

Now measure resistance between pot lug 3 and C7 right (+)..

[broomhandle]

at 200k I get 4.5

[antonis]

So, NFB gain branch is OK..

Check for pot lug2 & lug1 connections..

[broomhandle]

So now check Lug 1 and 2: resistance  C7 right (+)..

the connections of lug 1 and 2 solider looks good.

[antonis]

Sorry but I tend to forget your initial issue.. 

So, let's get it from the beginning:

Check all pot connections to respective items..
e.g Lug 1  to IC1A pin 6, C5, C6 & R12..
Lug 2 (wiper) to C5 & R9
R9 to IC1A pin 3..

[broomhandle]

I am a little confused again. Are you asking to get continuity (beep)? or a measurement?

Lug 1  > IC1A pin 6, C5, C6 & R12
Lug 2 > C5 & R9

R9 to IC1A pin 3.. (?)

Sorry but I tend to forget your initial issue.. 

So, let's get it from the beginning:

Check all pot connections to respective items..
e.g Lug 1  to IC1A pin 6, C5, C6 & R12..
Lug 2 (wiper) to C5 & R9
R9 to IC1A pin 3..

[antonis]

Check for proper connection and value of everyone item and wiring inside red frame..

[broomhandle]

Finally replying... thanks again for the help..

on my MultiMeter using 200k Ohm.

R9 = 100.1
R10 = 4.8

C5 = 40.8
C6= 54.0
C7 = 143.5 (side does say 1uf)

100kB = 90.8

IC = 4.0-2.0

Im not sure if the caps are the correct measurement. And I am not sure about the IC. I used red on the 1st hot pin, and took each pin. Not sure if I collected the right measurements..

thanks for helping the noobs. These projects are really fun, thanks to people in these forums

[iainpunk]

have you considered an Audio Probe?


it goes to your amp and you can test for guitar singal at several parts of the circuit!
cheers

[broomhandle]

Yes, I have a probe. The problem is am not sure what to test. The circuit works. Its is just a low fizzle. Like a bad cap or something. Or Bad IC. not sure...

[antonis]

The circuit works.

The distortion knob does nothing.