Valhalla issue

[PKRPedals]

I have noticed a couple quirky things with my Valhalla since building it. It has the same squeal/oscillation that my pineapple has when the gain is up around 2 oclock. Also when turning down the eq section all the way, it kills the volume. I run my cable from the power amp out to the front of the amp, it actually sounds better to me this way, and the pedal acts like a mute when you switch it off, but this my be normal for it to do that. Just thought I would bring it up. I have used all my guitars with this pedal and the pineapple and they all cause the squeal. I thought my Les Paul was different but turns out it does it to. These are the only 2 pedals that I have this issue with and I can't seem to figure it out. I reran my cables in the pineapple with shielded cables and that may have helped a bit, but it still has the squeal. My Thermionic and Thermionic Deluxe don't have the squeal. Now with all that said, these pedals sound amazing but I have to roll off my volume just a bit to make the squeal go away. I can deal with it but would rather it work properly. Any ideas?

 

[PKRPedals]

Anybody? I have gone back through the Valhalla and nothing. I pulled it out of the box and went over each solder joint. I swapped out each IC one at a time. Still has the squeal with the gain above 2 oclock.

 

[Chuck D. Bones]

The Valhalla has a Fender tone stack, so it's normal for the volume to go to zero when TREBLE, MID and BASS are all zeroed.

The Pineapple & Valhalla are two very different pedal designs. It's interesting that they would do the same thing.

If you turn the guitar's volume down, does the squeal go away?

Would you like to post some pictures of the insides of your Valhalla?

 

[PKRPedals]

Yes, you can turn the volume on the guitar down or turn the gain down and it will go away. If you play a chord, it will go away until the strings stop. Here’s a pic

 

[Chuck D. Bones]

Does turning a tone control on the Valhalla affect the pitch? How about the tone control on your guitar?

And yes, if you use the Power Amp output of the Valhalla, it will go mute when you switch the pedal to bypass. It sounds better using the Power Amp output because C19 rolls off the treble on the Normal output. If you want to get the Power Amp output sound on the Normal output, then try reducing or removing C19.

 

[PKRPedals]

Turning the tone controls has a small amount of affect. Not as much as the gain

 

[Chuck D. Bones]

Is it installed in a metal box in the pic? Looks like some kind of textured plastic in the background.

 

[PKRPedals]

No it’s out of the box

 

[Chuck D. Bones]

Does it squeal when it's installed in a metal box, with all of the shielding and grounding the the box provides?

 

[PKRPedals]

Yes sir

 

[Chuck D. Bones]

And if you unplug the guitar, does it squeal then?

 

[PKRPedals]

I’ll have to check that and get back to you

 

[PKRPedals]

Chuck the squeal is there with the guitar unplugged. Definitely something in the pedal?

 

[Chuck D. Bones]

Absolutely. All the parts I can read look right. I can't read any of the ceramic or aluminum caps. The aluminum caps look like they're facing the right way. What are you using to power this beast?

 

[PKRPedals]

I've got an isolated power supply that has several 9 volt and a 12 and 18 volt supply. I tried it in the 12 volt spot and it still squealed there.

 

[Chuck D. Bones]

Please verify that all of the ceramic caps are the right value. Are the jacks making good metal-to-metal contact with the box? Lotta powder coated boxes have paint on the inside that needs to be sanded off around the jacks.

 

[PKRPedals]

I did verify the caps. I’ll check the connection to the box

 

[PKRPedals]

I checked the box and it turns out there was some over spray. I sanded that out and put it all back together and the squeal is still there. I also noticed that if I turn the treble knob down, I can add more gain. But then it gets real dark and muddy.

 

[Chuck D. Bones]

Do you mean that if you turn the TREBLE down, you can turn the GAIN higher before the squeal sets in?

There must be some coupling between the input and output causing the oscillation. Either from the proximity of wires or via the ground or power rails.

Where do you have the VOL set and does it affect the squeal?

Can we get some pix of the board in the box?

Do you have an audio probe?

 

[PKRPedals]

Yes if I turn the treble down, I can add more gain. The volume doesn’t seem to affect it. I can send you a pic inside the box but even when it’s outside the box, the cables are separated. I don’t have an audio probe, I need to build one.