SOLVED Help with Total Bender (PCB Guitar Mania)

[neiltheseal]

Hi everyone.

I just put together a Total bender from PCB Guitar mania. I have managed to get the Mk1 and Mk2 working but am having trouble with the Mk3. I'm hoping someone can help.

This is the silicon version and in the Mk3 transistors are 2n3904.

Currently I can get a very faint signal what is very spluttery. Sounds like the transistors are not biased properly, although the trimpot do not really affect this.

Someone in a facebook group suggested I put a 100nf capacitor in c3.4 where the build docs (link here) said to put a jumper. This has helped somewhat and now I get an audio signal (before that there was nothing)

Does anybody know what might be the issue here?

For voltage :q3 collector is 8.48v, base is now -0.01v and emitter is 0v.

Thanks in advance!

 

[neiltheseal]

I'm with you @idlebydesign, my Total Bender board arrived the day I discovered this thread from @neiltheseal. Hoping all the advice here will help put together a full functioning build with this one.

BTW, I just completed PCBGM's "Ultimate Pharaoh" and it had a few issues on the board and in the build docs too (docs have wrong clipping order for the rotary switch and wiring the 5th and 6th clipping options need more tweaks than the build docs indicate). Not a huge deal (and the pedal sounds great) but definitely unfortunate.

Good luck. I hope you can get it working. As you can see i managed to get Mk3 working as GE but not Si. Mk1 and 2 worked fine as silicon.

I have had a few issues with PCBGM's build docs as well. The Electric Lover claimed to work with a v3207. However this did not work for me. The consensus in the PCBGM facebook group was that it would only work with an mn3007. I used this and it works perfectly

 

[idlebydesign]

I'm with you @idlebydesign, my Total Bender board arrived the day I discovered this thread from @neiltheseal. Hoping all the advice here will help put together a full functioning build with this one.

BTW, I just completed PCBGM's "Ultimate Pharaoh" and it had a few issues on the board and in the build docs too (docs have wrong clipping order for the rotary switch and wiring the 5th and 6th clipping options need more tweaks than the build docs indicate). Not a huge deal (and the pedal sounds great) but definitely unfortunate.

I was actually going to try my hand at a Pharaoh build after the Total Bender. I saw

 

[idlebydesign]

Hey Neil (@neiltheseal ) I am hoping you can help me out. I had a few questions about the Total Bender you made.
1. What transistors did you end up using? The building document, doesn't specify and I was hoping for any suggestions.
2. Where did you get the box film capacitors you used for most of the non polarized capacitors? They look tiny enough to fit the tight spaces. I'm having difficulty finding box film capacitors that fit in the tiny spaces.
3. Any idea what the left and right switches do? The building spec doesn't really outline this too much. Obviously one is an on-off switch, but I don't know which one it is, and what does the other switch do?

Thanks,
Travis

 

[neiltheseal]

Hey Neil (@neiltheseal ) I am hoping you can help me out. I had a few questions about the Total Bender you made.
1. What transistors did you end up using? The building document, doesn't specify and I was hoping for any suggestions.
2. Where did you get the box film capacitors you used for most of the non polarized capacitors? They look tiny enough to fit the tight spaces. I'm having difficulty finding box film capacitors that fit in the tiny spaces.
3. Any idea what the left and right switches do? The building spec doesn't really outline this too much. Obviously one is an on-off switch, but I don't know which one it is, and what does the other switch do?

Thanks,
Travis

Hey Travis.

1 - For the silicon version I used 2n3904 in Mk1 and BC109 or Bc109. It doesn't matter all that much. I socketed them to try different ones. You could probably use 2n5088 or 2n5089.

For the germanium I found a matched set on the internet. I think it's worth doing this as I have read the HFE is specific in this circuit. Aion FX has quite a bit of detail in their build docs for Phobos Germanium Fuzz. Just google matched tone bender germanium transistors. The part number doesn't really matter. Mine are russian transistors.

2 - All of my capacitors are from Tayda. If your caps don't fit you can always bend them sideways. I've done this on other builds.

3 - One of the foot switches turns the pedal on/off and the other is a slight volume boost. From memory you can use the volume boost with the total bender turned off so you can boost other pedals in the chain too.

I hope you get it going. It is quite fun.

 

[neiltheseal]

I bought these transistors specifically. I'm really not sure what the model number is, bit I don't think it matters.

Germanium Transistor Sets : diyguitarpedals.com.au, A shop for all diy guitar pedal enthusiasts!

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If you're in America you could go to smallbear or somewhere. They have them. As the Mk 3 is a 3 knob pedal I suppose you could get that set. But as you can see by the ones I bought they weren't specific for any model of tone bender.

Internal Components - Transistors - Germanium - Germanium Setups - Tone Benders and Similar - Small Bear Electronics

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