# 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?


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## 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.


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## 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?


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## 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


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## 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.


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## PKRPedals

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


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## Chuck D. Bones

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


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## PKRPedals

No it’s out of the box


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## 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?


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## PKRPedals

Yes sir


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## Chuck D. Bones

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


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## PKRPedals

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


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## PKRPedals

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


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## 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?


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## 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.


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## 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.


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## PKRPedals

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


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## 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.


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## 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?


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## 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.


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## 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?


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## zgrav

PKRPedals said:


> I don’t have an audio probe, I need to build one.


than make it so....


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## Chuck D. Bones

One of the places I want to probe is the power supply rails


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## PKRPedals

Chuck
I have been over this pedal with a fine tooth comb. I have checked all the resistors and caps for correctness and orientation. All my diodes are in correct and the correct ones. I swapped out the IC's just to be sure. The squeal is affected by the Treble, Mids, Gain, and/or Presence. It seems to be affected by volume but I think it just makes it louder. If I plug into the power amp out or into the loop, it still squeals. Thoughts?


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## Chuck D. Bones

I'm gonna suggest that we temporarily disable one stage at a time to get an idea how much of the circuit is participating in the oscillation.  We won't get very far without an audio probe, so you need to make or buy one.


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## PKRPedals

Let me make one and then we can continue. Probably be later this week. Thanks for your help so far. This will definitely be a learning experience. I have never used an audio probe.


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## PKRPedals

update: Out of curiosity I built another Valhalla. Guess what...It squeals just like the first one. What is it with this pedal? I moved it away from the amp and it still squeals. I saw a Youtube vid earlier and the one in the vid squealed just like mine does. I know others have built this pedal and had good luck. I'm at a loss here. I've watched Youtube vids of the actual VH4 and it doesn't do that. It does get a little noisier when the gain is cranked but no squeal.


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## music6000

PKRPedals said:


> update: Out of curiosity I built another Valhalla. Guess what...It squeals just like the first one. What is it with this pedal? I moved it away from the amp and it still squeals. I saw a Youtube vid earlier and the one in the vid squealed just like mine does. I know others have built this pedal and had good luck. I'm at a loss here. I've watched Youtube vids of the actual VH4 and it doesn't do that. It does get a little noisier when the gain is cranked but no squeal.


This might Help :
http://guitar-fx-layouts.42897.x6.nabble.com/Diezel-VH4-td43035.html


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## Chuck D. Bones

Interesting read.  It's easy enough to tell if the charge pump has a problem using a DVM and an audio probe.  If the plan is to build another Valhalla without understanding what's wrong with the first one, then I can't help.


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## music6000

Try a 7660SCPAZ, Try a MAX1044 also. Pull one from a working pedal!
Post Pictures.


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## PKRPedals

Thanks, I will give that a try.


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## music6000

PKRPedals said:


> Thanks, I will give that a try.


Are you using 9v or 12v to Power it? Make sure your Charge Pump is TC1044*S* or 7660*S.*
Someone @ FSB also suggested trying a buffered pedal before it as it worked with their Clone PCB squeal.
Using shielded cable on Input & Output Jacks is also suggested by another.


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## Chuck D. Bones

If changing the charge pump does not solve the problem, try pulling out IC1 and see if the squeal stops.  If if does, then we know the problem lies somewhere in the circuit near IC1.  If the squeal persists, pull IC2. Repeat with IC3, then IC4.  At some point, the squeal will stop.


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## PKRPedals

I'll try my boss ds-1 in front and see if that works. Thing is, I would like to be able to use the pedal without trickery to make it work. It's either a faulty part or something I did. I'm going with faulty part because I've built 2 and they both squeal using parts from Tayda. Up until this point I haven't had any issues with Tayda stuff, but I guess it was inevitable. Thanks for the suggestion.


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## PKRPedals

Chuck D. Bones said:


> If changing the charge pump does not solve the problem, try pulling out IC1 and see if the squeal stops.  If if does, then we know the problem lies somewhere in the circuit near IC1.  If the squeal persists, pull IC2. Repeat with IC3, then IC4.  At some point, the squeal will stop.


Ok I will do that this afternoon.


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## music6000

Chuck D. Bones said:


> If changing the charge pump does not solve the problem, try pulling out IC1 and see if the squeal stops.  If if does, then we know the problem lies somewhere in the circuit near IC1.  If the squeal persists, pull IC2. Repeat with IC3, then IC4.  At some point, the squeal will stop.


Yes Chuck, But after the pulling  & squeal stops, will the pedal still work.


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## music6000

PKRPedals said:


> Ok I will do that this afternoon.


Can you Double Check that your 5232 Zener's are correct values!


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## PKRPedals

They are 5232B. Is that wrong?


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## music6000

PKRPedals said:


> They are 5232B. Is that wrong?


Part Number is Correct, But test it anyway as below:


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## PKRPedals

5.4 volts is what I get


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## Robert

You aren't the first person to have oscillation issues with this circuit.  (and the issue seems to affect several different vero / PCB layouts)

As music6000 mentioned, at least one person found that a shielded input wire helped.         It's odd that a buffer in front helps, considering the first stage of the circuit is a unity gain buffer.  

(EDIT: Nevermind I see them in your pic and they're correct.)


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## 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?


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## PKRPedals

music6000 said:


> Are you using 9v or 12v to Power it? Make sure your Charge Pump is TC1044*S* or 7660*S.*
> Someone @ FSB also suggested trying a buffered pedal before it as it worked with their Clone PCB squeal.
> Using shielded cable on Input & Output Jacks is also suggested by another.


I checked my charge pumps and they are 1044s and 7660s. I swapped the 1044 for the 7660 and it still squealed. I did put my boss pedal in front and that stopped the squeal.


Robert said:


> You aren't the first person to have oscillation issues with this circuit.  (and the issue seems to affect several different vero / PCB layouts)
> 
> As music6000 mentioned, at least one person found that a shielded input wire helped.         It's odd that a buffer in front helps, considering the first stage of the circuit is a unity gain buffer.
> 
> Just a random thought, make sure R29 and R31 are both 10 ohm and not 10K by some chance.


I was very careful with the resistors on this build, I’ve had that bite me before. I can put my ds 1 in front of it, just plugged in and not on, and there is no squeal at all. It is almost completely quiet. It’s a great sounding pedal aside from the squeal.


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## Chuck D. Bones

I usually think that shielding the input wire is overkill, but in this case it may be necessary. For shielded wire to to be most effective, the separated center conductor and shield leads at each end must be as short as possible. You should be able to keep each under 1/2 inch or so. If you don't have shielded wire, twist the green & black input wires tightly, like 5 turns per inch, and see if that helps.  Twisted wires are not as effective as shielding, but it's a whole lot better that individual wires. Shielding the output wires (both pairs) could also help, but try the input side first.

The DS-1, or any other buffered bypass pedal, helps because it presents a low impedance source at the input to the Valhalla.  Any stray signal that would be picked up on the Valhalla's input gets shunted to ground by the preceding pedal's output buffer.

The input buffer is unity voltage gain, but it has extremely high current gain. It can be thought of as a very sensitive receiver with the input wire as the antenna.


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## PKRPedals

I replaced the input with shielded cable and it still squeals. I think it may just be one of those that squeal. Could a buffer be installed on the input  instead of using another pedal to solve it, maybe?


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## music6000

Chuck D. Bones said:


> I usually think that shielding the input wire is overkill, but in this case it may be necessary. For shielded wire to to be most effective, the separated center conductor and shield leads at each end must be as short as possible. You should be able to keep each under 1/2 inch or so. If you don't have shielded wire, twist the green & black input wires tightly, like 5 turns per inch, and see if that helps.  Twisted wires are not as effective as shielding, but it's a whole lot better that individual wires. Shielding the output wires (both pairs) could also help, but try the input side first.
> 
> The DS-1, or any other buffered bypass pedal, helps because it presents a low impedance source at the input to the Valhalla.  Any stray signal that would be picked up on the Valhalla's input gets shunted to ground by the preceding pedal's output buffer.
> 
> The input buffer is unity voltage gain, but it has extremely high current gain. It can be thought of as a very sensitive receiver with the input wire as the antenna.


I was looking at the Original PCB guts & the LM2940CT-12 is bent at right angles & screwed down to the PCB through the top hole, Does that need to be Grounded.
Also the jacks are PCB mounted so no leads!


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## PKRPedals

I looked at that also but it is grounded through the middle leg. I put my meter on it and it's showing ground. That's interesting about the PCB mounted jacks. I know there was one guy on here that built one and said he had no issues, so I don't know what he did different. There was also another guy that had the squeal. I watched the one video on Youtube for this pedal and it squealed around 2 o'clock.


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## music6000

PKRPedals said:


> I looked at that also but it is grounded through the middle leg. I put my meter on it and it's showing ground. That's interesting about the PCB mounted jacks. I know there was one guy on here that built one and said he had no issues, so I don't know what he did different. There was also another guy that had the squeal. I watched the one video on Youtube for this pedal and it squealed around 2 o'clock.


Some have upped the 47pf cap to 560pf to get rid of Squeal but it muddies the sound.
Apparently the Original has a Ferrite Bead resistor type which is used to shield unwanted noise.
Try putting some over the Input & Output leads, There are Hollow type & Clamp type available.


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## Robert

PKRPedals said:


> Could a buffer be installed on the input  instead of using another pedal to solve it, maybe?



Ideally I'd like to find out what in the heck is plaguing these things (because it's not just you).... 

But, as a last alternative, I will get some mini buffer PCBs worked up today that can be inserted into effects like this. (or any other case where you might need a tiny buffer).


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## PKRPedals

I would love to find out and not use a band-aid for it. But there are apparently other guys that are building these with different pcb's and they are having the same issue.


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## Chuck D. Bones

Here's the thing about the squeal.  It's an instability.  It's non-linear.  A circuit can be right on the edge of oscillating and not oscillate.  A circuit can be just past the edge and oscillate like a &^*#$@#.

You can measure the resistance of a wire from the jack to the board and read a number close to zero.  But that's not the whole story.  There can be some inductance in the lead and that might make the difference between oscillating and not oscillating.  Board-mounted jacks have significantly less lead inductance.

I can see how Vero boards can have oscillation problems because they don't have ground planes.  I've built a few Vero boards and so far (knock on wood) I have been pleasantly surprised by a lack of oscillation and noise problems.

Try the ferrite beads.  Might just be the ticket.  Dialing back the bandwidth a little on each stage might help too.


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## PKRPedals

I’ll try the bead first and get back with you. Hopefully it will work but if not, that will be one more thing tried


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## music6000

PKRPedals said:


> I know there was one guy on here that built one and said he had no issues


I'm assuming they plugged into their pedalboard & had a Buffered pedal in Front & are probably in for a Surprise as a Stand Alone pedal!


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## PKRPedals

That could be very true. I'm going to install the ferrite bead tomorrow and see what that does. Maybe Pedalpcb will come up with a small buffer to add to the input so that an extra pedal isn't needed to kill the squeal.


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## Chuck D. Bones

Adding another buffer inside the box may not help.


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## PKRPedals

You don’t think adding it in the input would work? I don’t know if it would or not, I was just thinking the the boss pedal going in stopped the squeal so surely adding a buffer at the input would.


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## Chuck D. Bones

It really depends on the coupling mechanism.  If the stray coupling that causes oscillation is on the board itself, then a buffer inside the box will fix it.


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## PKRPedals

I tried the ferrite beads and they didn't work. I also did a buffer on breadboard, the basic buffer from muzique. It stopped the squeal but was really noisy.


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## PKRPedals

I did a breadboard circuit of a Klon style buffer and put it in the input and that stopped the squeal. Maybe something to think about adding it to the board on the front end?


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## Chuck D. Bones

music6000 said:


> Yes Chuck, But after the pulling  & squeal stops, will the pedal still work.



No, but that's not the point.  We're pulling IC1 as a diagnostic to help us narrow down where the problem lies.


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## Chuck D. Bones

The fact that adding an off-board buffer helps makes me think the squeal is stray coupling on the board, probably due to the proximity of traces.  I can't find anything suspicious on the top layer of the board, but maybe there is something on the bottom side.


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## PKRPedals

It could be. When you look at the original, it is spread out on a much larger board.


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## 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?


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## music6000

Chuck D. Bones said:


> No, but that's not the point.  We're pulling IC1 as a diagnostic to help us narrow down where the problem lies.


I was just making some light hearted Humour. I agree that the traces are further apart on the Original & this being more Compact can cause it to be more prone to Oscillate just like the other versions of this circuit available out there.
If a Klon type buffer fixed the issue then Everybody is happy, Unless they are a ''True Bypass'' Only type!


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## Robert

music6000 said:


> If a Klon type buffer fixed the issue then Everybody is happy, Unless they are a ''True Bypass'' Only type!



The original is buffered bypass, but the additional buffer could still be inserted into a true-bypass config if desired.

This is one of the older layouts here, it might be time for an update to re-route traces and clean things up a bit...


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## PKRPedals

Robert said:


> The original is buffered bypass, but the additional buffer could still be inserted into a true-bypass config if desired.
> 
> This is one of the older layouts here, it might be time for an update to re-route traces and clean things up a bit...


Interested. Even if it has to go into a larger enclosure, that would be fine. The original is pretty large, and sometimes size matters.


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## Robert

You built two of these, right?

Have you patched both of them up with a buffer, or just one?


BTW you think this one is big?   You should see the monster I'm considering tracing next.....


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## PKRPedals

I did. I only put the buffer on the one but both circuits do exactly the same thing. If you need me to, I will verify the other is good also. The one that is in my avatar is the one that I play and just stick my Kliche in front of it and it works perfect.


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## PKRPedals

Robert said:


> BTW you think this one is big?   You should see the monster I'm considering tracing next.....


Interested.


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## Chuck D. Bones

music6000 said:


> I was just making some light hearted Humour. I agree that the traces are further apart on the Original & this being more Compact can cause it to be more prone to Oscillate just like the other versions of this circuit available out there.
> If a Klon type buffer fixed the issue then Everybody is happy, Unless they are a ''True Bypass'' Only type!



Ha ha ha ha ha, I totally zoned on that one.  
My concern is that _if _this board is prone to oscillation, the Klon buffer may not be a reliable fix. Could work for some builds and not others, or could work for a while and then one day, at the most inconvenient moment, start oscillating.


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## PKRPedals

I’m going to tie it into the input of the finished one tomorrow and see if it works. I feel pretty sure that it will, if only temporary. Maybe Pedalpcb will update this board and spread it out some, maybe that will do it. I'm enjoying being part of research and development. lol


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## PKRPedals

I finally got around to adding the buffer in to the finished pedal and it got rid of the squeal as it did on the test board.


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## benny_profane

Have you tried a charge pump IC from a different vendor than Tayda?


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## PKRPedals

I did something pretty cool. I built a switcher and put a buffer in the first loop. That is where the Valhalla will go if it’s on the board. Hooked it up and no squeal. Here are some pics of the switcher. I had some guitarpcb boards so I used them.


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## PKRPedals

Pedal board with switcher is up and running and the Valhalla is working great. The buffer definitely stops the squeal. 3 different buffers worked on the input.


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## BurntFingers

When you mention the buffer, is that something at the switch? I see they offer breakout boards for the c bypass, so if a buffer was desired, you'd just use one of those?


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## PKRPedals

No. I put the buffer on the input. I made a switcher with a buffer in it and that took care of the squeal.


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## wirrl

I also finished the Valhalla a while ago. It sounds amazing, but of course squal after 2 o clock ^^
So what is the most efficient way to make it work with a buffer without building a separate switcher that will go to the input of the Valhalla?

Or has it to be done like you did?

Regards,
Patrick


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## music6000

wirrl said:


> I also finished the Valhalla a while ago. It sounds amazing, but of course squal after 2 o clock ^^
> So what is the most efficient way to make it work with a buffer without building a separate switcher that will go to the input of the Valhalla?
> 
> Or has it to be done like you did?
> 
> Regards,
> Patrick


This is all that is needed to be installed if you can build it on Vero
You want the TL072 Layout :








						Klon Buffer
					

Collection of vero (stripboard) & tagboard layouts for 100s of popular guitar effects, with over 500 verified designs. DIY your own boutique effects!




					tagboardeffects.blogspot.com
				




I tried to show it roughly to Scale


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## music6000

This is my "Always On" Klone Buffer Eyelet version I designed & built around 5 years ago, Electro's & Caps are on the Underside.
The Enclosure measures 90mm x 35mm ( 3  1/2 '' x 1  3/8 '' )
The 3mm Cap screws hold the FR-4 Eyelet Board in place with a Nylon Hex Riser.
A couple are in Germany somewhere...


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## music6000

Valhalla  wth Klon Buffer Mock up :








						Klon Buffer
					

Collection of vero (stripboard) & tagboard layouts for 100s of popular guitar effects, with over 500 verified designs. DIY your own boutique effects!




					tagboardeffects.blogspot.com


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## PKRPedals

wirrl said:


> I also finished the Valhalla a while ago. It sounds amazing, but of course squal after 2 o clock ^^
> So what is the most efficient way to make it work with a buffer without building a separate switcher that will go to the input of the Valhalla?
> 
> Or has it to be done like you did?
> 
> Regards,
> Patrick


The easiest thing to do is put a Boss pedal in front of it. You don't have to turn it on, just have it there. I built a switcher with a buffer built in and it works great. I tried the buffer that Music6000 is suggesting and it works perfect, so that's another way to go also. Don't give up on it though, it's a really good sounding pedal.


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## music6000

Here is another Mockup showing the  Tayda Klon Buffer PCB placement , That would be what I would use :









						Klon Buffer DIY PCB Guitar Effect
					

DH Electro Acoustics - Get It Fast - Same Day Shipping




					www.taydaelectronics.com
				








__





						Klon Buffer
					

This simple and effective buffer improves the high frequency degraded by long cables or pedal chains.



					www.taydakits.com


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## 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?


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## familybezerker

I solved my oscillation problem! It was my switching power supply. Using a non-switching power supply fixed it.

I got the idea from one of bajamans earlier posts on FSB where he said his power supply whined.

I have no whine when the guitar is plugged in. If there is no input into the pedal, it will while above 60% gain but putting the Valhalla in front of a buffer pedal solves this.

I shielded the input and output wires but have no way of knowing without unsoldering what effect this had on the final result.

Now - since I have an real VH4 pedal, when comparing side by side they are very close. The character and sound is all there.
The real one is a bit more crisp - more hifi. I wonder if this is due to the Nichicon and Wima caps in the original plus they have an OPA2134 in IC1 and I have a TL072. I may try upgrading these components to see if it brings it close. The huge yellow Wima cap in the original may have to be bent in some way to fit inside the enclosure.

[[I ordered this Valhalla kit from Musikding. I realized after the fact that one difference between their Valhalla kit and their Benzin VH4 kit is that the Benzin VH4 kit includes the OPA2134. However Valhalla kit BOM has the correct C25k pots but I received B25k with it.]


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## Chuck D. Bones

Some switching power supplies are very noisy.  Some have stability issues.

As for the sonic differences, it could be down to component tolerances or the opamps.  If you have film caps, you probably won't hear the diff between brands. If you replace ceramic with film, that you will probably hear.


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