SOLVED Valhalla Distortion Noisy Squeal at high gain...

[RobertJay]

I'm sorry, not sure if this is a general question, a troubleshooting question, or what? Maybe there is no problem? Is this build such a high gain beast that I should have a squeal when the gain is past 2:00 / 2:30. I only noticed this last night as I finally got to run my guitar through it. When building, I always use a loop station pedal with riffs and test tones loaded in. No problem there. But with actual guitar it's noisy. I used my Les Paul and Fender strat. Double coils on both, wish I thought to use the single coil pickup just for more comparison. I'm curious to again double check my component values, I will trace out anything around the gain circuit of course, but... What do ya think? Does this sound right? Assume I should be using a suppressor or gate anyway? Or should this not be happening?
Also came back to add that I did swap out the power adapter as I have come across some where a faulty power source was actually the culprit. I didn't swap out instrument cables though. That too. But I see some very helpful replies already here. Thanks in advance.

 

[mdc]

Assuming everything is built correctly, try swapping out the opamps for other TL072s.

If that doesn't work, and you have some, try a TL062 in one of the gain stages (probably the final one?) and see if that clears it up. The TL062 is the lower-power version or the same device and can sometimes help with ticking/squealing/etc.

I'm guessing you're not seeing an issue with the loop station because of the buffer built into it. Try sticking the valhalla behind a boss pedal and see if it clears up. It could be something as simple as cable capacitance on the output causing the squealing - the buffer will often cure that. What happens when you have the pedal engaged but unplug the input cable? Does it go bonkers?

 

[mdc]

Some other stuff that might work.. try increasing the values of C2 C4 C8 and C11 a bit?
Add 100n MLCCs across +12V and ground / -12V and ground to block out high frequency stuff?
I'd start with swapping the opamps and see if you get lucky that way though, I'm guessing they're socketed so it's the easiest thing to try!

 

[temol]

Oscillation seems to be built in feature of diy version of the VH4 pedal And it's free of charge
It's quite common issue with this pedal. I recommend spending some time reading freestompboxes thread

Diezel VH4 Pedal

Just got my VH4 pedal today. Pretty cool idea getting that CH3 VH4 tone from a pedal. Definitely a lot of chunk to say its solid state. I use it in a preamp config blended with a boogie Tri-axis with custom 5 band eq i built into a boogie 2:90 power amp

www.freestompboxes.org

and also comments section

Diezel VH4

Gotten a lot of requests for this one and I finally bit the bullet and laid it out. It's the pedal version of the 3rd channel on Diezel's VH...

effectslayouts.blogspot.com

Diezel VH4

Collection of vero (stripboard) & tagboard layouts for 100s of popular guitar effects, with over 1000 verified designs. DIY your own boutique effects!

tagboardeffects.blogspot.com

and of course this forum.

I'd start with shielded IN/OUT wires. Sometimes it helps.

 

[RobertJay]

I suppose I should also now isolate the Valhalla and see if I have the noise without the Boss buffer....

 

[RobertJay]

Hello all. Thanks. I checked all of those links out. I see this is quite common. Now, an Admin answered an old question for me instructing me on how to work around this PCB's normal input and output so as to wire it up to a 3pdt wiring board. I think this bypassed the pcb's buffer.... And as for shielded cables or wiring inside the build? I'm unaware, is there a chance my spools of wire aren't shielded? Gotta read up more.

 

[RobertJay]

Yeah, Let's not go crazy spending more time on this idiot, aka , me. My original inquiry to the forum was the need for a footswitch to be wired up just to test the initial circuit assembly. I was told how to bypass the switch, which bypassed the internal buffer. I didn't know or think to wire it as designed for the final build. This might be on me. I'm on it.

 

[music6000]

Wiring it this way took out the buffer. Let's assume that's what we have going on? I'm sure I can wire up the way it's intended and still run the effects together .

'' Pictures are worth a thousand words ''
Can you show Good pictures of the PCB showing all the Resistor & components!!!
This is an updated PCB, all the stuff on this forum relates to the previous PCB issues.

 

[RobertJay]

Oscillation seems to be built in feature of diy version of the VH4 pedal And it's free of charge
It's quite common issue with this pedal. I recommend spending some time reading freestompboxes thread

Diezel VH4 Pedal

Just got my VH4 pedal today. Pretty cool idea getting that CH3 VH4 tone from a pedal. Definitely a lot of chunk to say its solid state. I use it in a preamp config blended with a boogie Tri-axis with custom 5 band eq i built into a boogie 2:90 power amp

www.freestompboxes.org

and also comments section

Diezel VH4

Gotten a lot of requests for this one and I finally bit the bullet and laid it out. It's the pedal version of the 3rd channel on Diezel's VH...

effectslayouts.blogspot.com

Diezel VH4

Collection of vero (stripboard) & tagboard layouts for 100s of popular guitar effects, with over 1000 verified designs. DIY your own boutique effects!

tagboardeffects.blogspot.com

and of course this forum.

I'd start with shielded IN/OUT wires. Sometimes it helps.

I just got the noise to stop when I happened to move the input wire out of the way. Someone else just told me to make sure I keep the input wire out of the way and away from the board...

 

[mdc]

Probably a good idea to use shielded input wire then, just in case it gets jostled in the enclosure.
RG147 coaxial is what everyone seems to like - it can be fussy to strip/prep.

 

[RobertJay]

Probably a good idea to use shielded input wire then, just in case it gets jostled in the enclosure.
RG147 coaxial is what everyone seems to like - it can be fussy to strip/prep.

I will order this now. I was / am in the middle of replacing the in and outs to and from this pcb and the 3pdt footswitch board with a pre-tinned rigid wire. I may be able to shape and bend the wire so as to run around the enclosure and avoid the pcb. I was also thinking of wrapping it in electrical tape. Would that help? Or is this an EMI type signal interference that needs a special shield? Maybe RG 174? I see that coming up.

 

[music6000]

I will order this now. I was / am in the middle of replacing the in and outs to and from this pcb and the 3pdt footswitch board with a pre-tinned rigid wire. I may be able to shape and bend the wire so as to run around the enclosure and avoid the pcb. I was also thinking of wrapping it in electrical tape. Would that help? Or is this an EMI type signal interference that needs a special shield? Maybe RG 174? I see that coming up.

Do you have your In & Out jacks at the top like in the BOM:

 

[RobertJay]

No. I use the audio in jack pad for the signal in but go to a 3pdt footswitch board from the board out pad which is the yellow wire at bottom right in pic.