Wampler pinnacle clone question

[alphadog808]

Hey guys,
 I was hoping someone could maybe chime in on a pinnacle build I'm working on.  I finished building the pinnacle with a vero layout from tagboard.  It's not boxed and some of the wires are long, etc, and I'm testing with all the knobs on full.  

I notice that if I turn on boost switch, I get a constant whine.  

When I turn on the vintage/modern switch to modern I get a whine and the sound is very tinny.  It could be because the knobs are all on full, not sure, need to double check.

Heaven forbid if I were to have them both on at the same time!  

Anyways, I was looking online to see if anyone else had that type of problem, and noise problems see relatively common.  One thing that caught my eye tho, is I saw a perfboard of the pinnacle by a user here and while I'm no EE, it seems both the vintage/modern switch and boost switch are wired up differently.

Here is tagboards.


Here is diystompboxes one.


I think the user was also saying he dropped the value of the 1M resistor on the input to bring down noise as well.  IIRC doing that is lowering impedance...I guess that would lower noise as well?

The other thing is I have trimmers on Q5 and Q6.  Would swapping those out for regular resistors maybe lower noise as well?

[J0K3RX]

Have you tried to use an audio probe?

[alphadog808]

Have you tried to use an audio probe?

Unfortunately, I don't have any fancy testing equipment, I'm only armed with my DMM.    I figure even if I had one, I wouldn't be sure where/what to check anyways...

[J0K3RX]

Have you tried to use an audio probe?

Unfortunately, I don't have any fancy testing equipment, I'm only armed with my DMM.    I figure even if I had one, I wouldn't be sure where/what to check anyways...

Very simple... bout as simple as it gets, but very useful! You probably already have an audio probe and you didn't even know it
https://www.youtube.com/watch?v=jWvIfDSxbIk

http://www.guitarforum.co.za/amps-speakers-and-valves/audio-probe-locate-noise-in-a-circuit/

[GibsonGM]

Build the audio probe, man....no WAY does anyone want to look thru vero layouts, ha ha!  A real schematic + the probe should get you into the area where the trouble is pretty fast.

If you want to do this hobby, you must have a DMM and the probe.  For the cost of 1 capacitor, I think it's within most peoples' grasp!     You can just run a line from a CD player and throw a song into your circuit, then 'zap it down' with the probe right to where your trouble starts.   It's like magic )

[alphadog808]

wow, that is a great tool!  I'll have to make one.  I did have a couple questions tho.

I saw that some people used a 63V 100nf cap, but others use 10mf cap.  Does it matter which I use?  As for voltage, I assume as long as you're over 9v you're good.

I can see how this can analyze where there are breaks in a circuit, but in my case, my circuit is good(sorta) it's just that I get a whine on the boost and vintage/modern switch.  I guess if anything I can see where the signal starts to whine and mod that component from there?

Oh, and can I blow anything up if I accidentally hit multiple things at once, etc?

Thanks guys, this looks like a GREAT and easy to use troubleshooting tool!

[bluebunny]

Oh, and can I blow anything up if I accidentally hit multiple things at once, etc?

Yes!  I was probing a mini-tube circuit (voltages, not audio, but the "prodding around" part is much the same...).  I managed to short a high-ish voltage to a heater connection.  For a brief moment, I had created a light-emitting triode.      And now it's a dark-emitting triode...   

[alphadog808]

Oh, and can I blow anything up if I accidentally hit multiple things at once, etc?

Yes!  I was probing a mini-tube circuit (voltages, not audio, but the "prodding around" part is much the same...).  I managed to short a high-ish voltage to a heater connection.  For a brief moment, I had created a light-emitting triode.     And now it's a dark-emitting triode...  

Bummer to hear man.    I hope it's harder to do on stompboxes...

So I got further, but now face another issue...of course.
I got it boxed up, I have shielded(and grounded to one side only) cabling for the input and output and here's what I got...with all knobs on full(for testing)

-With boost on..
  - pedal squeals with or without guitar plugged in.  4x510k pulldown from input to ground did nothing.

-With boost off...
  - pedal squeals only when guitar is unplugged.  a 3x510k pulldown from input to ground silenced the squeal in this mode.

- Doesn't matter if I use a battery of wallwart, same symptoms.

- Squealing completely goes away in both modes with a boss pedal(Boss AC2! haha) is in front.  

Now, I could just lug a boss pedal around, but that's kinda..weird...haha!  I heard this works because of the boss buffering.  So, with my situation, is there any easy way to build an internal buffer for it or does anyone have any ideas on how I can mod the board to get rid of the squeal?  

I heard replacing the j201s with 2N5457s helps with only a little loss of gain.  If so, do I need to change them all out?  Or is this an experimental thing?

I'm going to look over the boost section with my non EE eyes, so I don't think I'll get too far.  Thanks in advance for any suggestions.  

[bluebunny]

Bummer to hear man.    I hope it's harder to do on stompboxes...

It was a stompbox...  

- Squealing completely goes away in both modes with a boss pedal(Boss AC2! haha) is in front.  

Now, I could just lug a boss pedal around, but that's kinda..weird...haha!  I heard this works because of the boss buffering.  So, with my situation, is there any easy way to build an internal buffer for it or does anyone have any ideas on how I can mod the board to get rid of the squeal?  

If a buffer is the answer (and it may not be), then you could build a simple JFET buffer like this one at AMZ?

[alphadog808]

Thanks bluebunny.  Actually, the more I think about it, the more I think I'm going to see if I can get around this without building a buffer.  I know other users have solved squeals/whines in different ways, I just think I might be missing something or need to mod a part or two.  

I did realize that I did NOT use shielded cable for the boost 3 and boost 6 wires and maybe they should be?  Looks like Q1 and Q3 are tied to the boost.  

Also, I noticed the 2 layouts in this thread for the boost are different.  The vero has nothing hooked up for lugs 1 and 4, but the other one has something on each lug.  Anyone have any ideas?

I have ordered some 2N5457s, so I will try replacing some J201s as well to see if that helps without damaging the tone.

[alphadog808]

So, update...

I am now able to keep the pedal quiet in all states, UNLESS the boost is on.  If it's on, it squeals with or without anything plugged in.  Once it's squealing, the frequency of the squeal changes as I turn the knobs.  Happens with battery or wallwart.  The boss pedal in front still silences the squeal.

Last night I cleaned up more wiring but I think what REALLY helped and what might have been my problem except for the boost part is...


That bridge on the 3pdt switch.  I was making it with a piece of wire that I had humped up in the air like an inchworm.  I figured it would keep stuff out of the way, etc.  It did seem that once I changed it to a flat piece of wire going point to point, it got much quieter...or it could have been a fluke.  But that was a common thing in my previous whiny builds...

In trying to fix the boost squeal, I tried shielded cable for ALL the gain pot wires, no dice.  In fact, the noise got worse.  Even though it was shielded cable, I think as the wire is so inflexible, it made it hard to lay down nicely.

I tried shielded wire for the 2 boost wires, still squealing.  

The only thing I can think of is that volume pot 1 is a pretty long run and it's unshielded.  pot 2 is shielded, and pot 3 is a pretty short run.  If that doesn't work, I think I'll try to replace some of the j201s with 25457Ns and see if I can get it working that way.  

Anyone have any ideas of a component change I can make to help remedy this?  I guess I could try lowering the pulldown from 1M to something lower?

Hopefully if I can't get this sorted out maybe my trials can help other pinnacle makers in the future...

[Pojo]

I would think the biggest help would be to keep the input and output leads to the board as far apart as possible. Even if it also means redoing the 3pdt so that the led column is in the center with the input and output columns at opposite sides.