Diezel VH4 Pedal  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.

Re: Diezel VH4 Pedal

Postby psychepool » 20 Apr 2018, 09:12

I read all the contents and try to make my own layout. I have some questions that I need to confirm.

1. I want to run it through the 9v power supply for convenience.
I am going to get 9v and drive it by making bipolar doubler through 7660 or 1054.
What is worrisome is whether to supply 18v bioplar power or 12v bipolar power through a 12v regulator.
Is the 18v bipolar power source too much choice? Is it better to supply 12v through the regulator?

2. Are R28 and R34 100R or 1K?

3. There is a controversy about the tone stack in connection with the middle pot connection.
Is it correct to connect according to the current circuit diagram? Or is it just like connecting a vintage amp with a tone stack?

Thank you for always helping me to do happy DIY. please answer about my question.
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Re: Diezel VH4 Pedal

Postby mnemonic » 21 May 2018, 22:27

I finally got around to building this pedal on Bugg's PCB. Great pcb as always, sounds great and works perfect.

I used the requisite TC1044SCPA and its silent, no switching noise.

pictures attached.
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Re: Diezel VH4 Pedal

Postby the_ungod » 24 May 2018, 11:10

Does any one knows whats the point of the send? I understand that it may be a buffer if we dont make the pedal true bypass. But using a 3PDT does it make sense to include C3 and R4?!

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Re: Diezel VH4 Pedal

Postby Optical » 25 May 2018, 02:19

It's useful as a key input for noise gates or recording a dry signal.
Other than that you can leave it out
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Re: Diezel VH4 Pedal

Postby icziko » 29 May 2018, 21:58

Guys, thanks for this fantastic schematic and this thread - it is very useful and informative.
I built using Tagboard layout and pedal sounds fantastic.
I had problem with oscillation when gain is above 60%. I tried option with 560pF instead of 47p in C10 but additional cap decreased gain a lot and entire pedal became muddy. I prefered to have better sound but oscillation above 60%.
After, I used JHS Little Black Buffer in front of pedal (clone also as per Tagboard layout) and I can crank gain to 100% without any oscillation except when my MIDS are really hi (like 70-80%) and gain at 100% than oscillation came back. Anyway I did not plan to use total gain but I will try idea to shorten connection wires between pots and board. But just to let You know, buffer pedal helps a lot but not fixed situation completely.
I also had some squeal floor noise/background - I could play but it was annoying - I figured out I used 7660A instead of 7660S. Change to 7660S solved noise issue.

I have a question - maybe somebody had similar issues so it could help me out.
My Gain Pot from 0-40% of rotation is giving me clean sound. Then between 40-50% there is big jump and it gives me hi gain stuff. It does not look like original pedal shown on Youtube. Generally on promo videos I saw that this pedal can also deliver some blues crunchy stuff, however in my situation it gives me clean to 40% and then hi gain stuff.
I already replaced pot because I thought it might be good solution but I was wrong thus gain pot is still as it is.
Does anybody have similar issue?

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