jfet vulcan layout?

[troubledtom]

i can draw one out for perf, but if someone allready did one on vero or perf , i thought i'd be lazy. i tried the search function
W/ nothing come'n up
              thanx,
                 - tom

[aron]

I just did it like I usually do. By hand, on the spot. Took 1 hour to finish the board.... not bad if you only need one.

[cab42]

Tom,

I'm in the middle of building the JFet version using MartyMarts vero-layout for the BJT-version. I don't see why it couldn't be done with
proper component substitution and a little twisting of the pins on the j201's.

However I have some problems with the circuit, but I think its related to some "wrong" resistor values as I used what I had in my drawer.
On my way home today I will buy proper values, and see how it goes.

Question: When I read voltages on the jfets, I should get around 4.5V on the drain pin. Is this correct? And does it apply to all jfet circuits?

Regasrds

Carsten

[aron]

When I read voltages on the jfets, I should get around 4.5V on the drain pin. Is this correct? And does it apply to all jfet circuits?

It doesn't have to be exactly 4.5V but it should be somewhat close. It should work +- .5V, or maybe even more.

[cab42]

Aron,

Thanks

Carsten

[EdJ]

Hey,that is cool!
I was working on a stripboard layout but can`t seem to get it small enough to fit in the boxes i have:(

Ed

[cab42]

Hey,that is cool!
I was working on a stripboard layout but can`t seem to get it small enough to fit in the boxes i have:(

Ed

It's correct. Joe's multistage distortions tend to be very long, but hey whats wrong with a shoebox on your pedalboard.

I had the same problem, when I tried to make an Obsidian layout.

Regards

Carsten

[aron]

I have been able to fit all of them into the width of a 1590BB box easily.

[Khas Evets]

Here's one I threw together last night. It's not verified yet. It's pretty tight, but I wanted to make one tighter than the one floating around here, so I could squeeze it into a 125B box.

[troubledtom]

Here's one I threw together last night. It's not verified yet. It's pretty tight, but I wanted to make one tighter than the one floating around here, so I could squeeze it into a 125B box.

that's bad ass!
      -tom

[Khas Evets]

Reduced by a third from the previous one (32 wide vs. 22)! I just hope all the components fit.

[Khas Evets]

You might want to swith the source resistors and caps. The boxed cap is a little wider than pictured.

[cab42]

Here's one I threw together last night. It's not verified yet. It's pretty tight, but I wanted to make one tighter than the one floating around here, so I could squeeze it into a 125B box.

What a cool layout!!! I like the color coding for 9v and ground.

I got Marty's vero layout working last night with jfets. It sounds great.

Now, however, I am very tempted to rebuild using your layout. On the other hand: if it ain't  broke, don't fix it.

Regards

Carsten

[Khas Evets]

Thanks. If you've got it working, don't bother. I did add reverse polarity protection and a filter cap, which might be worth adding to yours.

[analog kid]

I'd love to hear more opinions on those who build the FET version here compared to (IF ) you've built the 5089 vers. also! I know there are other threads about this but never have I got any definitive tonal or dist.character opinions.   I have built the 89 version and added a tone control (SWTC) right into the 470k divider ..which made it a good candidate along with high gain in general, for no need in added gain staging. worked out great except my TONE control CW to CCW goes from full Treble to Full Rolloff about halfway down rotation then inexplicably gets just slightly trebley again from halfway down to Full CCW.   Too stupidly wonderful for maybe. Obviously it's something that's a problem at the input lug of the tone pot Ideas what causes my tone control to do that would be great too.

Damn did I just Hijack this bad boy or what? My bad , I've just been hesistant to rebuild a whole new vulcan for a very slight difference in character BUT my extreme liking for FET device Dist's and seeing this cool vero layout (mine is on vero too) made me think about it even more
Vulcan Kicks HARD, no doubt (either way I'm sure )

[cab42]

MartyMart wrote this:

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"

in this thread: http://www.elixant.com/~stompbox/smfforum/index.php?topic=41223.0

I haven't build 5089 version, but the above quote made the decision for me. I have only tried mine through my candy-box Ruby amp,
(allthough with a decent speaker) on family-friendly-11-o'clock-in-the-evening-volume, but I was amazed. My wife did'nt hear the the actual playing but she did hear my unarticulated yelling of joy.

The only substitution I made was a 150pF instead of the 100pF, because that was what I had. I guess it makes it little brighter?

Next up is adding a tone control.

Regards

Carsten

[EdJ]

Hey Khas!
Looks like you did a great job.
I am going to build it asap and let you know.
Thank you very much!
Greetings,Ed

[EdJ]

I ran out of 1Meg resistors so i went out to buy a few this afternoon,turns out the guy gave me 1M2`s
You`re right i should have checked,it wasn`t the first time.
Do you guys think these will do(well for now at least)?
Thanks,
Ed

[Khas Evets]

It doesn't matter for the pulldown resistor. The other three are used for biasing. The diodes are supposed to be forward biased with a small current. I don't think this should be a problem. It will slightly shift the DC bias voltage, but that shouldn't be a problem. I'd say give it a shot.

[EdJ]

Thanks Khas,i will.

Ed