JFET Vulcan is cool!

[aron]

I built it last night and the first thing that amazed me was the sheer amount of gain/distortion! WOW.

OK, I will have to test it out at gig volumes. The pedal is a little bright for my tastes and the low end is a little thick for my guitar but I will be tweaking it soon. As soon as my iPod mic is available I will have lots more samples to do.

I built it with greenies and used perfboard (it's just faster for me).

Thank you Joe!!!!!!!!

Aron

http://analogalchemy.diystompboxes.com/pedals/jfetvulcan.html

[PenPen]

Does indeed look like a cool circuit. I'm fast becoming a fan of jfets, I need to order some more. I just wish I could get the biasing right for max gain from a single jfet stage. I think I'll try the first stage of this here and see how it turns out.

[aron]

I think I will try the Hammer tone control on this one and if that doesn't pan out, I will try the Shaka HV tone control from Jack.

[Ed G.]

I'm going to have to breadboard it. I've always had good success with Joe's circuits.
If it's too 'hot' maybe try lower gain fets like the 2n5457?

[aron]

hehehe I want it hot. Very hot! I have enough low to mid gain pedals. I need one that has tremendous distortion! 

[WGTP]

That's what is on on of my breadboards right now, exept the first stage is the BJT version.  Cool stuff. 

[aron]

OK, did more work on it. I used a 220pf for the 2.2M resistor high pass filter. I used a 4.7uF on the last stage. I added Mark's simple tone control - but used a 50K pot and also used a 10K resistor in series with the .01uF film cap to ground. I need to work on the tone filter at real gigging volume.  I used 1N4148 but the difference is nil compared to 1N914.

oh and I need to order another L280s from Bill Lawrence 

[MartyMart]

Very cool !
I love the 2N5089 version, is this more "touch sensitive"  ?
Probably more "amp-like" too ....
I still have "Dr Boogey" on the list ..... !


Marty.

[Joe]

The gain of each stage is set with the drain/source resistors. They are almost too high in that circuit but I wanted to use 3 stages. Try a 5 stage version with 1k source/~4.7k drain. 

[Steben]

It's a funny way to draw Jfet's! A boxed BJT! Looks a very easy build... not?

[bancika]

sounds interesting, any clips/layout?

[jmusser]

I think what I'm the most thrilled about, is that after all this time, the explaination of the build sounds like you just built your first one! I'm  glad you're not burned out, and the passion is still there. As Marty said, the 5089 version is awesome. I haven't built the jfet version yet. The Blackfire is wonderful too, as is anything else Joe makes.

[aron]

As Marty said, the 5089 version is awesome

Yep, built that a while ago. My version is totally awesome BUT unfortunately picks up noise... I mean, a lot of noise. It's raging, killing, but man, the noise is too much on my version (which was modded a lot BTW).

The Blackfire is one of the most amazing Si transistor pedals out there. Really amazing - like when I first built Gus' 3 transistor fuzz. 

I KNEW the JFET Vulcan was going to be incredible because as soon as I plugged it in.... my amp started to howl, then Howl, then HOWL with insane gain! 

[mac]

Joe's circuits are the best among non-comercial stuff. 99% chance to work when you turn it on for the first time.
The obsidian overdrive should be renamed to obscene overhowling 

Right now I'm working on a germanium version of the vulcan with Ge diodes. I have a lot of Ge mid-gain fuzz pedals which is what I like. But I want a fuzz with more gain, ie, a metal Ge fuzz. I have some mid-gain, low-leakage Ge transistor, hfe around 200. I guess they will fit nice into the vulcan. I was considereing a Ge big muff but the diode compression of the vulcan seems more appealing.
Have anyone tried Ge diodes with the 5089 or fet version???

mac

[aron]

I would imagine NPN Ge transistors might drop right into the Si Vulcan. I never tried it (might have to rebias). Might be really cool!

[MartyMart]

I guess the thing to do, would be to use 50/100k trimmers from 9v
that will give you some "bias" tuning, may need to look at emitter values
for Ge though ?
MM

[Doug_H]

Aron, I think you'll like the Hammer tone control. I stuck one on the output of my Hwy89 and I can use it with any of my amps, with them set up for any tone. It's real effective for de-fizzing a pedal so it gets along with many different amp setups.

Doug

[WGTP]

I built a PNP BlackFire stage and used GE's in both locations, as well as a BS250 Mosfet.  Ended up using 2N5087's being the gain addict that I am.  Also, the GE's were a bit too wooley for me.   

[MartyMart]

I built it last night and the first thing that amazed me was the sheer amount of gain/distortion! WOW.
Thank you Joe!!!!!!!!

Aron
http://analogalchemy.diystompboxes.com/pedals/jfetvulcan.html

I put one together this morning and I'm blaming you aron for this    !!!
( miss-spent adulthood !! )
It's great, very different from the 5089 version, more harmonics and more "amp like"

Cheers,
Marty.

[aron]

Great!!!!!!!!

Oh I see you can build quickly as well! I will be trying it tonight at the gig! hehehehe