Diezel VH4 Pedal  [schematic]

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Diezel VH4 Pedal

Postby kh602 » 29 Nov 2016, 23:53

Just got my VH4 pedal today. Pretty cool idea getting that CH3 VH4 tone from a pedal. Definitely a lot of chunk to say its solid state.
I use it in a preamp config blended with a boogie Tri-axis with custom 5 band eq i built into a boogie 2:90 power amp so vh4 is coming out
of one side of my cab and TA out of the other so its blended in stereo etc....

Not sure if its worth what it is from thomann. Yeah the sound is cool and works well to the power amp but the build quality isn't really there
in terms of material used for the case and things. Still need more time to mess with it as i only just got it and hooked it up.

Anyway i took some quick shots in case anyone is interested.
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Re: Diezel VH4 Pedal [Gut shots]

Postby askwho69 » 08 Dec 2016, 13:42

There is a Jfet version somewhere else here. I made it years ago and became my main pedal. It is a cool copy of Diezel amp's preamp.
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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 09 Dec 2016, 19:27

Yeah I did the same with the diefet but it's far chunkier and has more depth to it than that. The diefet sounded a little fizzier to me. The pedal is cool. Still a lot of cash to splash out on a pedal but I suppose I have done worse.
I will pull it a part more at a later date and get shots of both sides of the Pcb and maybe someone can trace it up as I don't have the time to lately.

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Re: Diezel VH4 Pedal [Gut shots]

Postby zamguitar » 09 Dec 2016, 20:04

kh602 wrote:Yeah I did the same with the diefet but it's far chunkier and has more depth to it than that. The diefet sounded a little fizzier to me. The pedal is cool. Still a lot of cash to splash out on a pedal but I suppose I have done worse.
I will pull it a part more at a later date and get shots of both sides of the Pcb and maybe someone can trace it up as I don't have the time to lately.


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Re: Diezel VH4 Pedal [Gut shots]

Postby J0K3RX » 10 Dec 2016, 01:42

This will probably be an easy trace... all we would need is one or two good shots of the other side and consider it done! Too damn close not to do it now man 8) God, this pedal is silly expensive... :shock: Diezel must not want to move a lot of them at that price..!!?

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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 13 Dec 2016, 21:01

I have just taken more shots front and back tried to cover all angles and things but obviously uploading on here
is limited yet every pic is at least 1-3mb. Anywhere i can upload them maybe zip them up as 1 download
or something and still comply with forum rules?
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Re: Diezel VH4 Pedal [Gut shots]

Postby marmaliser » 14 Dec 2016, 11:05

You can get a free 2GB dropbox that will do the job
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Re: Diezel VH4 Pedal [Gut shots]

Postby J0K3RX » 17 Dec 2016, 04:15

Just upload them as attachements like you did with the other pics.. If the other side is like the back then there is no need for higher resolution than the other pics. Resize them if they are too big and get them down to around 800k each. That should be plenty good enough if they are clear and the lighting is good like the other pics. The traces on the back are mostly quite large and easy to follow, no reason the other side would not be the same. I see some hair line traces also leading to via's and up under components and stuff but pics of the other side should connect all of the pieces of the puzzle together. Sometimes I shine a bright LED flashlight through the board and I can see right through like an x ray..
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Re: Diezel VH4 Pedal [Gut shots]

Postby J0K3RX » 17 Dec 2016, 20:38

You can sign up for an account here, 10gigs for free

https://www.box.com/pricing/individual
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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 19 Dec 2016, 13:09

J0K3RX wrote:You can sign up for an account here, 10gigs for free

https://www.box.com/pricing/individual


Here are all the pics front and back. https://app.box.com/s/eqpa1fe9nd8f6gbq8wfxkqw85lxax054

there is 48 in total from all different angles. hope this helps

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Re: Diezel VH4 Pedal [Gut shots]

Postby J0K3RX » 19 Dec 2016, 19:06

kh602, excelent pics! Hate to bother you further but, do those pots have any values on them that you can see without lifting them? I have a few pots like that so I am fairly sure the values are on the bottom facing the board.. We can probably guestimate what they should be in the tonestack since it looks like your average marshall type stack with standard values judging from the cap and resistor values.
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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 20 Dec 2016, 19:52

J0K3RX wrote:kh602, excelent pics! Hate to bother you further but, do those pots have any values on them that you can see without lifting them? I have a few pots like that so I am fairly sure the values are on the bottom facing the board.. We can probably guestimate what they should be in the tonestack since it looks like your average marshall type stack with standard values judging from the cap and resistor values.


Measured values of the pots (most are in rheostat config, i assume master and treb are potential dividers at a glance).

Gain pot = 159.7k
Bass pot = 566k
Mid pot = 24.82k
Treb Pot = 262.3k
Master Pot = 10.93k
Pres Pot = 21.07k
Deep pot = 25.35k

Hope this helps

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Re: Diezel VH4 Pedal [Gut shots]

Postby zamguitar » 20 Dec 2016, 20:08

I'm pretty sure the pot values are the same as the Zerrer pedal.
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Re: Diezel VH4 Pedal [Gut shots]

Postby Manfred » 20 Dec 2016, 20:24

Measured values of the pots (most are in rheostat config, i assume master and treb are potential dividers at a glance).

Gain pot = 159.7k
Bass pot = 566k
Mid pot = 24.82k
Treb Pot = 262.3k
Master Pot = 10.93k
Pres Pot = 21.07k
Deep pot = 25.35k


Thanks for sharing the pot values.
Could you please measure the pot values on the 12:00 position for to determine the pot curve type.
Please measure each values from tap to the ends.
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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 20 Dec 2016, 20:45

Manfred wrote:
Measured values of the pots (most are in rheostat config, i assume master and treb are potential dividers at a glance).

Gain pot = 159.7k
Bass pot = 566k
Mid pot = 24.82k
Treb Pot = 262.3k
Master Pot = 10.93k
Pres Pot = 21.07k
Deep pot = 25.35k


Thanks for sharing the pot values.
Could you please measure the pot values on the 12:00 position for to determine the pot curve type.
Please measure each values from tap to the ends.


all at 12 oclock
Gain pot = 32k
Bass pot = 105.5k
Mid pot = 12.64k
Treb Pot = 128k
Master Pot = 1.5k
Pres Pot = 1.1k
Deep pot = 2.85k

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Re: Diezel VH4 Pedal [Gut shots]

Postby zamguitar » 20 Dec 2016, 20:50

I'm having hard time figuring out the zener values D3, D4 and the gold cap next to the C28, this cap is responsible for the presence control, so it's value is critical.

I'm halfway done with the tracing.

When the pedal is in bypass mode, the "OUT TO POWER AMP" is muted, right?
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Re: Diezel VH4 Pedal [Gut shots]

Postby zamguitar » 20 Dec 2016, 20:55

The capacitor is C17
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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 20 Dec 2016, 21:00

zamguitar wrote:I'm having hard time figuring out the zener values D3, D4 and the gold cap next to the C28, this cap is responsible for the presence control, so it's value is critical.

I'm halfway done with the tracing.

When the pedal is in bypass mode, the "OUT TO POWER AMP" is muted, right?


I can't see the zeners unless i pull them off. it's 1N5 but no idea on the value underneath. c28 is 47uf 35v, c17 1uf 100v, c20 10uf 63v.

I dont use it in pedal mode but i assume so because when using the power amp output socket it's either on or off (the off state, there is no audio signal/true bypass using the power amp socket)
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Re: Diezel VH4 Pedal [Gut shots]

Postby zamguitar » 20 Dec 2016, 21:10

kh602 wrote:
zamguitar wrote:I'm having hard time figuring out the zener values D3, D4 and the gold cap next to the C28, this cap is responsible for the presence control, so it's value is critical.

I'm halfway done with the tracing.

When the pedal is in bypass mode, the "OUT TO POWER AMP" is muted, right?


I can't see the zeners unless i pull them off. it's 1N5 but no idea on the value underneath. c28 is 47uf 35v, c17 1uf 100v, c20 10uf 63v.

I dont use it in pedal mode but i assume so because when using the power amp output socket it's either on or off (the off state, there is no audio signal/true bypass using the power amp socket)



Thanks for the time you spent on this.

I can assume the zeners are there to prevent nasty opamp overload and throw a value just below the V+/V- or I can play with asymetrical clipping putting different zener voltages.

I think both ways would give interesting sounding results.
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Re: Diezel VH4 Pedal [Gut shots]

Postby kh602 » 21 Dec 2016, 22:33

zamguitar wrote:
kh602 wrote:
zamguitar wrote:I'm having hard time figuring out the zener values D3, D4 and the gold cap next to the C28, this cap is responsible for the presence control, so it's value is critical.

I'm halfway done with the tracing.

When the pedal is in bypass mode, the "OUT TO POWER AMP" is muted, right?


I can't see the zeners unless i pull them off. it's 1N5 but no idea on the value underneath. c28 is 47uf 35v, c17 1uf 100v, c20 10uf 63v.

I dont use it in pedal mode but i assume so because when using the power amp output socket it's either on or off (the off state, there is no audio signal/true bypass using the power amp socket)



Thanks for the time you spent on this.

I can assume the zeners are there to prevent nasty opamp overload and throw a value just below the V+/V- or I can play with asymetrical clipping putting different zener voltages.

I think both ways would give interesting sounding results.


No problem. anything else just let me know. i would be interested to see the schem.

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