Diezel VH4 Pedal  [schematic]

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Re: Diezel VH4 Pedal

Postby Jan1966 » 23 Jun 2017, 17:41

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Re: Diezel VH4 Pedal

Postby bmxguitarsbmx » 23 Jun 2017, 18:57

bajaman wrote:I am pretty certain it would sound the same with less expensive 100v capacitors though perhaps they used 630v types to justify the high price of the pedal or maybe , being a tube amplifier manufacturer, they simply had lots of these high voltage capacitors in stock already :hmmm:


bajaman:

What is your opinion on counterfeiting?

Do you feel that the market should not dictate the price of a product and that there should be some limit to what stompbox builders can earn?

Is there an "activist" role that DIY people should play to punish companies that charge above a reasonable limit?

Thanks! Curious to better understand these topics! :)
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Re: Diezel VH4 Pedal

Postby bajaman » 23 Jun 2017, 23:51

Hello bmxguitarsbmx
Since you are asking me personally on a public forum i will give you my answers - these are my opinions only and do not neccessarily reflect the views or opinions of any other member of this forum :wink:
What is your opinion on counterfeiting?

I do not think counterfeiting is good if the counterfeiter is using another person or company's good business name in an attempt to sell their own product to the "marketplace" in an attempt to fool the potential purchaser that the product is genuine. Behringer produces a large number of products that are derived from other manufacturers designs circuit wise but they do not advertise them as Boss, ibanez, tech 21, QSC, Peavey, Mackie etc, products, so in this sense would you say that they are counterfeiting ? Many companies in mainland China produce musical instruments such as guitars where they are clearly offering counterfeit product displaying the true owner's name such as Gibson, Fender, Rickenbacker, MusicMan etc. I guess they do not view counterfeiting as a crime in China.
:roll:

Do you feel that the market should not dictate the price of a product and that there should be some limit to what stompbox builders can earn?

Short answer is no to both questions :)

Is there an "activist" role that DIY people should play to punish companies that charge above a reasonable limit?

I don't believe so. If a company charges above a reasonable limit, they do not sell enough product to remain in business surely. I see no role for a DIY person to punish a company for any reason.
I do see DIY as a very satisfying way of learning how to build things differently - a great learning experience and very satisfying for the DIY builder when their actual build works first time, although this is not always the case and that is where the DIYer learns fault finding skills or enlists the help of more experienced DIYers to get his or her build working as desired. Incidentally many DIY folks that frequent this forum have gone on to become builders themselves and many of them produce fine products that are unique to them and not simply clones or copies of some one else's work - Brian Wampler comes to my mind.

cheers
bajaman :D

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Re: Diezel VH4 Pedal

Postby bmxguitarsbmx » 24 Jun 2017, 04:35

bajaman,
I really appreciate your time and thoughtfulness in writing your response. :)

DIY is fun and a fantastic way to spend the evening time. I was part of the BE OD project going on, and this VH4 is also up my alley. I am conflicted about this stuff. I wouldn't want to have a negative effect on the market.

In general, I think that reversing these designs could actually push innovation. Possibly and hopefully ;)

Best wishes,
bmx

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Re: Diezel VH4 Pedal

Postby bajaman » 28 Jun 2017, 06:43

After a few nights work I have shrunken the layout to fit inside a Hammond 1590BB enclosure - it will also fit inside the equivalent NSC enclosure :wink:
I decided to cut the board down so that the potentiometers, and sockets are connected by flying leads - this reduces the pcb cost by 50% and allows the use of any style of potentiometer and socket etc. :)
I have placed an order with OSH PARK for the minimum 3 boards, so will probably have a spare board available at some stage. Once i have actually built and tested the pcb I will share the board on OSH PARK. I think this is the best way of doing things in case of any pcb errors - i will publish some pictures of the board and pedal in this thread once built and tested :thumbsup
In the meantime here are some top and bottom views of the board layout for you all.
cheers
bajaman
Weasel V84 1590BB mini board bottom.JPG

Weasel V84 1590BB mini board top.JPG
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Re: Diezel VH4 Pedal

Postby 440hz » 30 Jun 2017, 02:37

Very cool, bajaman!

If you end up with a spare working board, I'd be interesting in buying one off of you.

If not, I'd be down to split an OSH Park order with someone, if anyone else is interested.
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Re: Diezel VH4 Pedal

Postby roseblood11 » 30 Jun 2017, 11:14

Bajaman,
if you don't plan to sell these boards yourself, they should be available via madbean, 1776 or Aion! Or maybe uk-electronic.de in germany?
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Re: Diezel VH4 Pedal

Postby bajaman » 30 Jun 2017, 13:11

Bajaman,
if you don't plan to sell these boards yourself, they should be available via madbean, 1776 or Aion! Or maybe uk-electronic.de in germany?



But first - I will build one - the boards are with the fabricator at the moment - enclosure and pots all ready - just need to get the board, populate and test it then we can discuss distribution etc.
The boards will definitely be available but let us not "jump the gun" until we have a fully built and tested working prototype - patience please :wink:
cheers
bajaman

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Re: Diezel VH4 Pedal

Postby 440hz » 22 Jul 2017, 06:07

Any more news, bajaman? Still waiting on those boards to come in?
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Re: Diezel VH4 Pedal

Postby edy_wheazel » 23 Jul 2017, 12:13

My contribution to this project.
I attached the schematic, layout and pcb. It fits in a 1590BB enclosure.
The pot's are not placed on the pcb (see schematic).
It's still UNTESTED, I will made this in a few days, after I get my parts.

Have fun!
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Re: Diezel VH4 Pedal

Postby bajaman » 23 Jul 2017, 12:21

Any more news, bajaman? Still waiting on those boards to come in?

I am still populating the pcb and waiting for some OPA2134 chips - i thought i had some but only had the single and quad versions :oops:
So far all the parts are fitting ok :thumbsup so won't be too long before i can run it up and verify it - I will have two spare boards so one is earmarked for you.
cheers
bajaman

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Re: Diezel VH4 Pedal

Postby orcl2 » 23 Jul 2017, 22:56

Waiting the result of your work! XD
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Re: Diezel VH4 Pedal

Postby bajaman » 25 Jul 2017, 00:56

Ok - built tested and verified working 100% :thumbsup
I didn't know the value of the inductance bead at the input so just bridged it with a wire link.
I am still waiting for my OPA2134 chips to arrive so in the meantime used a socketed TL072.
I ran it off a 12v 1A switching supply plug pack - opamps are running +10v and -10v rails.
my 12v plugpack whines log a baby (cheap chinese shit ) so i plugged in a Boss 9v adaptor and measured +7v and -7v on the opamp power supply pins - still sounds good even on lower supply voltage :wink:
I used 1u multi layer ceramic capacitors in place of the 1u electros - just because i have a ton of them :lol:
Here are some build pics.
I will share this board layout now on OSH PARK - search for bajaman and you should find it ok :wink:

IMG_3221.JPG

IMG_3222.JPG

IMG_3223.JPG

IMG_3224.JPG


cheers :thumbsup
bajaman
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Re: Diezel VH4 Pedal

Postby bajaman » 25 Jul 2017, 04:33

I have one spare board - $US10 includes airmail postage.
pm me quick if interested :wink:
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Re: Diezel VH4 Pedal

Postby bmxguitarsbmx » 25 Jul 2017, 07:33

How brutal is it? 8D
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Re: Diezel VH4 Pedal

Postby bajaman » 25 Jul 2017, 08:17

How brutal is it? 8D

very nice - low noise floor and very wide range of gain possible - nice for cleanish blues at low gain settings.
very different to the Friedman BE-OD in many ways but still a good high gain pedal to have.
I ran a few sims as well and it is easy to see why Diezel uses reverse log pots for the presence and deep (resonance) controls because with linear pots nothing much happens until the last 5% of clockwise rotation on the sims.
The presence on full, has almost 20db of boost at around 1.6kHz which is a very low frequency compared to the friedman presence circuit, and considerably larger :wink:
The deep control on full, puts a very sharp 20dB Q peak in the response at around 120Hz which is slightly higher than the friedmans bass control.
The 3 section passive tone circuit behaves very much like a typical marshall tone stack - nothing exciting here.
Overall a lot more flexibility tone wise compared to the Friedman, but the Friedman does a more convincing 100 lb violin tone and is a tighter crunch in my opinion.
Both pedals are completely different in many aspects of their design but both are worth having. the Friedman is a bit of a one trick pedal and it does that trick really well, but the Diezel is a lot more versatile and less prone to oscillation and noise artifacts.
Like comparing Fords and Chevs I guess :lol:
have fun and keep rockin'
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Re: Diezel VH4 Pedal

Postby bajaman » 25 Jul 2017, 09:49

I just ran some more sims - this time to investigate the clipping behaviour in an interactive simulation.
Surprisingly the first clip occurs in IC2b the third gain stage and AFTER the stage with the zeners in the feedback loop AND AFTER the back to back 1N4148 diodes - in fact removing the zeners and the 1N4148s from the simulation made no change at all to the output waveform. :shock:
Not sure exactly when or if these diodes have any effect on the clipping behaviour of this pedal but the primary clip appears to be within that third TL072 gain stage :!:

Okay I was inputting an 8mV sine wave signal at 1kHz when I measured the onset of clipping in IC2b.
I increased this signal level up to 130mV before i was able to detect any appreciable clipping behaviour BEFORE IC2b indicating that the diodes were now conducting - that is over 16 times the signal level which makes me wonder if the pedal would sound any different without the diodes in place at all :hmmm: :!:

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Re: Diezel VH4 Pedal

Postby Groovenut » 25 Jul 2017, 15:27

bajaman wrote:I just ran some more sims - this time to investigate the clipping behaviour in an interactive simulation.
Surprisingly the first clip occurs in IC2b the third gain stage and AFTER the stage with the zeners in the feedback loop AND AFTER the back to back 1N4148 diodes - in fact removing the zeners and the 1N4148s from the simulation made no change at all to the output waveform. :shock:
Not sure exactly when or if these diodes have any effect on the clipping behaviour of this pedal but the primary clip appears to be within that third TL072 gain stage :!:

Okay I was inputting an 8mV sine wave signal at 1kHz when I measured the onset of clipping in IC2b.
I increased this signal level up to 130mV before i was able to detect any appreciable clipping behaviour BEFORE IC2b indicating that the diodes were now conducting - that is over 16 times the signal level which makes me wonder if the pedal would sound any different without the diodes in place at all :hmmm: :!:

Baja, thanks for all the contributions! Very valuable info.
Most modern tube amp designs tend to clip the stage closest to the power amp first and it is usually biased as a symmetrical clipper, then the next stage closer to the input clips and so on until you get to the input stage. The main exception to this is the cold clipping stage many (Soldano, Mesa Rectifier, Peavey 5150, Engl) have in the 3rd stage. It is usually biased near cutoff and will clip asymmetrically and very early.

I find both the BEOD and VH4 pedal versions of the actual amps to be interesting from a design emulation standpoint. I don't think either get the actual sound of the amp but they get close enough for anyone who has never played the actual amp, to feel satisfied about their purchase. They are also good sounding units on their own regardless of comparison to the amps they are supposed to emulate.

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Re: Diezel VH4 Pedal

Postby bmxguitarsbmx » 25 Jul 2017, 22:17

Thank you Bajaman and Groovenut!

Interesting stuff. Interesting how two of the best high gain tube amp simulations are using tl072's! Who knew?!

The 1n4148's are a simple noise gate (my apologies if that is obvious). Signal at that stage is significantly steep to usually not impart too much crossover distortion, not that croddover distortion is bad.

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Re: Diezel VH4 Pedal

Postby bajaman » 25 Jul 2017, 23:13

Thanks for the clarification on the noise gate bmxguitarsbmx :)
and thanks for the tube amp explanation Groovenut - you are 100% here - most folks do not realize that it is the driver or phase inverter stage that overloads and clips first in 90% of all tube guitar amplifiers. The vain idea that someone can purchase a boost pedal to drive the front end of their amplifier into overload is of course total nonsense because the driver stage will saturate WELL before this could EVER happen :wink:
What I find interesting with this Diezel VH4 pedal design is the tone stack is AFTER the clipping 3rd stage whereas in a tube amplifier it is always BEFORE - and it is the TL072 clipping which is then modified by the following treble, mid, bass, presence and deep controls that defines the sound (plus the high cut filter tagged on the guitar amp output socket to roll off the fizz! )
:lol:
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