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DIYstompboxes.com  |  DIY Stompboxes  |  Building your own stompbox  |  JFET Vulcan 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: JFET Vulcan  (Read 15203 times)
aron
Administrator
Posts: 9758

Aron Nelson


JFET Vulcan
« on: May 07, 2008, 03:39:18 PM »

Since I have the mic out....

JFET Vulcan

http://diystompboxes.com/pedals/sounds/JFETVulcan5-7-08.mp3

JFET Vulcan with FX

http://diystompboxes.com/pedals/sounds/JFETVulcan5-7-08FX.mp3

Schematic:

http://diystompboxes.com/analogalchemy/
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WGTP
Posts: 2458


Re: JFET Vulcan
« Reply #1 on: May 08, 2008, 08:05:40 AM »

Do you like the Jfet or the regular Vulcan the best?  On the bread board I mix them.   We don't want Joe's cool stuff to get lost in all the distortions around hear.  icon_cool
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Stomping Out Sparks & Flames
aron
Administrator
Posts: 9758

Aron Nelson


Re: JFET Vulcan
« Reply #2 on: May 08, 2008, 11:26:44 AM »

I think I like the JFET one. It's one of the pedals I still have boxed. Yes, Joe's stuff is incredible.
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Marcos - Munky
Posts: 2676

Marcos Paulo Baliscei - Brazil


Re: JFET Vulcan
« Reply #3 on: May 08, 2008, 12:38:40 PM »

Aron, do you have the layout you used?
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aron
Administrator
Posts: 9758

Aron Nelson


Re: JFET Vulcan
« Reply #4 on: May 08, 2008, 02:01:39 PM »

I just wired by hand on perfboard like I always do.
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John Blund
Posts: 28

Jakob S.


Re: JFET Vulcan
« Reply #5 on: May 08, 2008, 03:04:40 PM »

Quite excellent! but I dont know if it's the guitar playing or the Vulcan that makes it sound good Cool
btw does the vulcan have any clean range?
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raulgrell
Posts: 202

Raul G - Portugal


Re: JFET Vulcan
« Reply #6 on: May 08, 2008, 04:25:51 PM »

I find myself doing a lot of mixing of designs, mostly using different kinds of transistors within each circuit.

I have found 2 mods to Joe's designs that really made the sound for me:

For the vulcan, put a BJT in the middle stage, with the gain slightly decreased in the first stage and increased quite a bit in the second... Kinda like a hybrid of the JFET and the BJT design...

And the Blackfire, put a TransFET booster in the place of the second stage. I haven't had the opportunity to experiment with MOSFETs yet, but I think it could sound pretty damn good in the output stage of a blackfire.
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MartyMart
Posts: 6059


Martin L / Berlin for a while


WWW
Re: JFET Vulcan
« Reply #7 on: May 09, 2008, 03:10:12 AM »

Great playing too aron !!
That's STILL one of my most treasured pedals :-)
A bit of an "unsung hero"  IMO 

Marty.
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"Success is the ability to go from one failure to another with no loss of enthusiasm"
My Website www.martinlister.com
cab42
Posts: 455

Carsten B. CPH, Denmark


Re: JFET Vulcan
« Reply #8 on: May 09, 2008, 07:02:05 AM »

I'm very fond of mine as well.

I experimented with a few different tone controls and finally added a BMP tone control.

Regarding layouts. I used Martys vero layout for the BJT-version. Twisting the pins on the jfets and changing a few components made it work for the jfet version.

However, I remember seeing a more compact vero layout somewhere.

Great sound and great playing, Aron!

Regards

Carsten


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aron
Administrator
Posts: 9758

Aron Nelson


Re: JFET Vulcan
« Reply #9 on: May 09, 2008, 11:47:10 AM »

The Vulcan does have clean range, although I use it for heavier sounds. It's a pretty darn good pedal. Mine fits easily in a 1590BB box. Raul, good ideas on mixing the two pedals!
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suprleed
Posts: 127

Adam P. from Cygnus X-1


Re: JFET Vulcan
« Reply #10 on: May 09, 2008, 12:11:52 PM »

Holy Crap! that sounded good!!! Shocked  What kind of amp are you running that into?

I've been looking for a good Vulcan sound clip for months.  Thx.  You have some toneful fingers my friend.  Love how it went from bluesy in the beginning to full on super lead in the middle to heavy chug at the end.  Nice, very nice.

[Me bowing in homage aka waynes world "we're not worthy."]  Smiley
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"That's the way I play" ~EC
aron
Administrator
Posts: 9758

Aron Nelson


Re: JFET Vulcan
« Reply #11 on: May 09, 2008, 12:17:21 PM »

This was my Traynor YRM-1. The cabinet is a 2x12 sealed back with greenbacks. I just close mic'ed it. I'm still looking for more clarity. I need to experiment more.
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aron
Administrator
Posts: 9758

Aron Nelson


Re: JFET Vulcan
« Reply #12 on: May 09, 2008, 12:20:37 PM »

oh forgot to say, as with the BSIAB clip, no pedal changes. All the sounds are volume knob and pickup switch changes.
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Constantin Necrasov
Posts: 1108

Constantin Necrasov


WWW
Re: JFET Vulcan
« Reply #13 on: May 09, 2008, 01:02:02 PM »

What will tighten the sound up and "clarify it" would be a 0.002 cap instead of 0.1 before the 1M gain control. In general - smaller caps throughout.
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aron
Administrator
Posts: 9758

Aron Nelson


Re: JFET Vulcan
« Reply #14 on: May 09, 2008, 02:11:07 PM »

yes. When I was using it, I was playing through my champ. Now I should try more mods.
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gaussmarkov
Posts: 1154


paul


WWW
Re: JFET Vulcan
« Reply #15 on: June 11, 2008, 09:16:01 AM »

fwiw, i made a project for this one.  i had a layout for the bjt version from years ago, so i updated it and posted it on gaussmarkov.net.  here's an Eagle3D render of the build:


it isn't verified, but i am pretty sure it's all good.  if you do verify it, please post.
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gaussmarkov.net:  layouts & eagle
Renegadrian
Posts: 2221


Adriano - Rome Italy


Re: JFET Vulcan
« Reply #16 on: November 29, 2008, 09:33:23 AM »

Well, some of you already know that I'm a metalhead and a "highgainer", so I started to buid this one back in may...
Then it was put on hold...I put the remaining components and wired with flying leads and no pots, just to try it...
Man, what a distortion!!! This will surely deserve a good box...
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Done an' workin'=Too many to mention - Tube addict!
corcia
Posts: 4


Re: JFET Vulcan
« Reply #17 on: December 08, 2011, 06:27:32 PM »

I'm currently building a JFET Vulcan, could someone describe the procedure to bias the JFETs?
thanks a lot!!!!!!!!
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WGTP
Posts: 2458


Re: JFET Vulcan
« Reply #18 on: December 08, 2011, 07:37:05 PM »

Do you have a VOM? Wink
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Stomping Out Sparks & Flames
corcia
Posts: 4


Re: JFET Vulcan
« Reply #19 on: December 09, 2011, 01:34:42 AM »

Do you have a VOM? Wink

if you mean a Volt/Ohm Meter  icon_redface, yes i do have one.
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