DIEFET: Jfet simulation of the Diezel VH4

Stompboxes circuits published in magazines, books or on DIY electronics websites.

Re: DIEFET: Jfet simulation of the Diezel VH4

Postby J0K3RX » 08 Oct 2012, 18:07

askwho69 wrote:if you want real diezel make a preamp tubes from the schematic you have. i love my diefet very dynamic and controls are cool... it's high parts count and big board but at-least it sounded big too hehehe :D its up to you though

By the way can you send me the schematic of Diezel amp?

Yeah, I have built the Diefet... I guess I shouldn't have been so hard on the Diefet in my last posts as it really does sound great and the controls are VERY dynamic as you stated! It's just not "my sound" you know.. I have played a real Diezel before and it really wasn't "my sound" either... Not a bad sound, just different feel etc.. I prefer ENGL and Marshall and a few others.. Diezel to me is a completely different beast! That being said, I would rather not try to build a Diezel clone using tubes from this schematic... Too much involved with tubes and the cost is not worth it to me. I have built a couple tube preamps and I was very satisfied with them! If I were going to build another tube preamp I would have to build an ENGL clone!

jymaze, did they do frequency analysis of an actual amp or was it a frequency analysis of a recorded Diezel amp or amps? If it was from recordings that may be why I am not hearing a real close resemblance? Again I am not saying that it doesn't sound good because it does and it does to a certain extent sound similar to a Diezel... The one I built worked great, tons of gain, great tonal control etc.. just didn't quite make THE Diezel tone to me?? The reason I ask about the frequency analysis is because I don't think, for example, using let's say some intro guitar sounds from some song will be accurate, kinda like people who make cab/speaker impulses using songs and what not...And they do! Those impulses almost always sound like garbage! So, my question is, if they had the actual Diezel amp sitting there in front of them, then why go strictly from frequency analysis? Why not open it up and trace it out, note the component values etc. and draw up a schematic?

It may just be that I am too picky in combination with my ears being shot out after years of screaming guitars and metal?

Another thing that I had noticed is that everybody that I saw on youtube using the Diefet were playing through the front guitar input of various amps... That in my opinion is not a good representation of the actual tone! Running it direct or into a power amp would be preferred, right?

On another note: In the near future I would like to make a "variant" of the Diefet leaving off that whole deep control TL072 and MAX1044 charge pump... When I built the Diefet I tried running directly from the output from the volume pot and got a VERY good sound! There are quite a few things that "I would do" to this preamp but, I am not sure that it would get it any closer to the Diezel sound but I am sure it would sound like a beast in any case!!!

askwho69 - The schematic I have (if you can call it that?) is an actual Diezel VH4 schematic but all of the component values have been removed.. no voltages... everything except the lines and component symbols have been removed. So, really all that you can see is the layout like there is a resistor here in this stage and it connects to this capacitor yada yada... So, it is for the most part useless except for checking the makeup and layout which is why I was saying that it doesn't match with the Diefet schematic.. totally different in that aspect...
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Re: DIEFET: Jfet simulation of the Diezel VH4

Postby jymaze » 11 Oct 2012, 13:42


I think they used multiple tone samples from a website and the Diezel was alone in the mix. It has limitations, but it is precise, as long as the samples are faithful to the real thing.
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Re: DIEFET: Jfet simulation of the Diezel VH4

Postby Freak » 15 Nov 2018, 10:20

I built a clone of this pedal and I was wondering how does it work that the preamp is so much louder than the gamp.
I think the tone of the gamp is very different, more darker.
is it possible to bring the gamp volume to the same level as the preamp?
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