Sabbath Distortion

[BuddytheReow]

Hey guys,

Just finished the circuit on a sabbath distortion. I alligator clipped it to test and I get virtually no signal coming through. The signal that does come through is incredibly faint and sounds not distorted. The pots appear to sound correct (volume, gain, etc). I did test the pots before soldering them in. Here are the voltages for the trannies, pins reading left to right:

q1 0 2. 8.7
Q2 0. 1.6 3.7
Q3 2.9 4.8 8.8
Q4 0 0.6 4.2
Q5 2.9 5 8.8
Q6 2 5 8.8

Any assistance would be greatly appreciated. I know I can count on you guys to help with this.

 

[BuddytheReow]

Gotcha. I’ll circle back here once a be boxed it up.

Thank you all!

 

[BuddytheReow]

OK. I've boxed it up and tested it again. The effect works, however I'm still having these gain issues where I hear a warble. I've linked 2 videos below with my daisy chain power supply. One video is only this pedal plugged in and you do hear the grounding noise. The second video I have multiple pedals plugged in, but not engaged and the grounding noise is cleaned up. See below link where I talk about this.

Daisy Chain Power Supply

Not sure if this is really an "issue", but I have a Donner daisy chain from Amazon. I can chain 5 pedals together. When I only have one pedal plugged in I get a lot of noise when engaged. However, if I have all of them plugged in I get very little noise when I engage a single pedal or multiple...

forum.pedalpcb.com

The work around is I simply don't turn the gain to max, but I don't think it should work like that. Can anyone assist?

IMG_0206.MOV

drive.google.com

IMG_0205.MOV

drive.google.com

 

[Nostradoomus]

Can we see a final gut shot? Some high gain stuff benefits from using shielded wire on the input/output.

 

[BuddytheReow]

What do you mean by shielded wire? Heat shrink? I just used 22 gauge hookup wire.

 

[Nostradoomus]

Like this, youll most commonly see it in your guitar patch cables. The outer braid goes to ground while your inner wire is for signal. I usually run them from the switch to the jacks with ground attached at the jack only, helps keep down interference in some situations.

 

[Nostradoomus]

Also you may want to sand the paint away from inside your enclosure where your jacks are sitting.

 

[BuddytheReow]

Would grounding be the issue why i hear this gain "warble"? Cant think of another word to describe it.

 

[Nostradoomus]

It might not be but it wouldn’t surprise me, improper grounding can lead to all kinds of oddities.

 

[BuddytheReow]

Also you may want to sand the paint away from inside your enclosure where your jacks are sitting.

It’s powder coated. Does that change anything? Hoping there’s a noob reason why I’m getting this issue

 

[music6000]

Input & Output Jack Tips ( Green & Yellow ) look like they could be touching Enclosure?
Are you sure all your Transistors are firm in the Sockets!

 

[Nostradoomus]

It’s powder coated. Does that change anything? Hoping there’s a noob reason why I’m getting this issue

Anything impeding direct metal on metal contact should be removed.

 

[BuddytheReow]

Input & Output Jack Tips ( Green & Yellow ) look like they could be touching Enclosure?
Are you sure all your Transistors are firm in the Sockets!

Jack tips are fine. Weird camera angle I guess. Will double check the socketed items.

 

[Chas Grant]

Double check the value of C12, I see a 4 on top of it, can't read the value though. It should be a 2u2. Not sure what the 4 is for.

 

[BuddytheReow]

Double check the value of C12, I see a 4 on top of it, can't read the value though. It should be a 2u2. Not sure what the 4 is for.

It’s a 2u2. The “4” that you saw was a temperature range. See pics.

 

[Chas Grant]

It’s a 2u2. The “4” that you saw was a temperature range. See pics.

Cool just wanted to make sure. I've had a high gain pedal warble before and the problem was a feedback capacitor.

 

[BuddytheReow]

I sanded down the enclosure where the jacks touch and doubled checked my socketed items. All are good, but I’m still getting the gain warble starting around 3 o’clock. I guess I’ll just have to live with it unless there’s another thing I’m missing. Maybe in my next tayda run I’ll look for shielded wire.

 

[Nostradoomus]

Maybe your C10 47pf cap has become unstable/microphonic. I really hate those little red disk caps and recommend you buy the yellow MLCC style, but for now maybe try swapping it out.

 

[BuddytheReow]

So, I've been playing around with the pedal and I think this has to do with grounding issues, particularly in my daisy chain. If I have all the power sources plugged in to the various pedals the gain warble virtually disappears. This may be a one time "fix", but I will try it again later this evening and see if there are any changes. I'll tag this as 'solved' if this goes away. I will also try swapping out the 47pf cap too just in case.

 

[Untro]

Maybe your C10 47pf cap has become unstable/microphonic. I really hate those little red disk caps and recommend you buy the yellow MLCC style, but for now maybe try swapping it out.

I noticed the dinky caps for the 47p, is a good rule of thumb to use MLCC in high gain situations? Or just whenever at all possible?

Also i want to make sure about the shielded wire thing as i have a sabbath to complete: the hot goes from switch to jack as normal, while the cold goes from switch ground to just being terminated at the jack, not attached to anything, on both input/output? And there shielded wiring available in 22/20 gauge?
Thanks for the info, its good to know that theres a few additional things to pay attention to when building high gain pedals.

 

[Nostradoomus]

I haven’t touched those little disk caps in years, MLCC or better for me.

As for the shielded cable hot goes to jack tip and switch, cold to jack sleeve or another ground point, easiest to get it on
The jack. I believe I have a spool of RG-174 cable that works well, I’ll double check when I get home but it’s 24 or 25awg on the inside. It’s not a cure all for noise but it’s helpful in cases where the input wire is running close to an LFO or opamp like in the Phase II.