Octup Vero Layout!

[KerryF]

Ok just did a vero layout for the Octup pedal from Tonepad.  Please let me know if this looks right.  I want to build it today hopefully.

Heres the link to the schematic and all from Tonepad: http://www.tonepad.com/getFile.asp?id=109

Heres my layout:


Also, I only have one of the 2N5457s.  Any substitutions?

[Seljer]

I believe you'd want a matched pair of JFETs for the octave effect to be most prominent in that circuit.

J201s would work, and MPF102s too I believe

[KerryF]

I may have 2 J201s.  If not, then 2 different ones wont work right?  I will check it out.  But first I want to know if the layout is right.

EDIT: Yes, I do have 2 J201s.  They will work right?

[Seljer]

It will work, however, the octave up might not be as strong

[KerryF]

Ok, well as long as the layout is correct, I will build it, and wait for another 2N5457.

When you say "it will work, but wont be as strong", do you mean 2 different types of JFETs, 2 J201s, or the layout?

[Seljer]

JFETs, even of the same type, are not all created equal.

http://www.geofex.com/Article_Folders/fetmatch/fetmatch.htm

[slacker]

If you check out the original circuit at http://www.geocities.com/tpe123/folkurban/fuzz/snippets you'll see that Tim used unmatched J201s.

[KerryF]

Ok, I guess I can use the J201s then.  Still waiting for layout verification.

[slacker]

yeah your layout looks Ok. You might want to swap C4 and R3 over, that way the leads from C4 won't cross the  jumper and R4.

[RLBJR65]

Yep layout looks good. 
I agree with Slacker, shouldn't have that jumper and resistor lead under C4.
You could move R4 to the left of Q2. Then move the jumper over to the right, in between R6 and R8.

Just a suggestion.
Richard

[KerryF]

Ok, took your suggestions.  Now im going to build it...

[KerryF]

Ok, I just finished building it.  I used J201s instead of the 2N4547s.  The only thing is that the pinouts are very confusing on it.  I think I figured out how they go in, but may have to think it through more tomarrow after some rest.  When I had it together, sound went through it and all.  The Volume and Bias pots work.  Theres no hi octave though.  Maybe this is because of the J201s instead of the 2N4547 or maybe wrong pinouts.  Anyone have any idea?

[jmusser]

I'll be interested to know if you get a decent up octave out of this. I built mine on perf a long time ago, and could never get anything but overdrive out of it. If I was to do a Pete Townsend windmill on it, I could get an up octave spike that immediately decayed. My personal opinion, is that this circuit is somewhat pick up specific. Meaning, that if you don't have a certain type of pick up that's pretty hot, that you're just not going to get anything out of it. I even tried it with boosts or ODs in front of it, and no dice. It and the Cicada I've had the same problem with, and no other up octaves, so I'm interested to see if it works for you, before I strip mine for parts.

[KerryF]

Well, I will let you know if it works.  I have pretty hot pickups.  I have a PRS Custom 24 Ten-Top 20th Anniversary guitar with the HFS (Hot, Fat, Screamers), and Vintage humbuckers and it didnt work yet.  It may be the transistors though.

Well anyway, heres some pictures so far of it.

Circuit Board:



With Offboard Wiring Strip and Pots:


Soldering:


I tried to get the components as close to the board as possible so it looks nice and neat.  One pot is for bias and one is for volume.  I still have to fix it up a bit in order to get it working.  As soon as I get it working, I will have some soundclips up.

[KerryF]

I just tried it with a fuzz and it works!

I think that the octave isnt as strong because I am using J201s.  Would using 2N5088s work?  It calls for the 2N4547s, but I only have 1.  So which do you guys think is better for the second pair of transistors:
1. J201s (Using Now and is a bit weak)
2. 2N5088s (I have enough of these but would they work?)
3. 2N4547s (Supposed to use but only have 1 right now)

[Seljer]

2n5088s are regular bipolar junction transistors, not JFETs which this circuit calls for. And by 2N4547 I assume you mean 2N5457?
really just try whatever pairs of FETs you have, the octave sound depends on the characteristics of each one of them.

Maybe try messing with the value of the resistor at the drain of the 2 FETs (R7 in your layout), I think it would affect the sound of the octave quiet a bit too.

[KerryF]

Ok I will check out voltages of some FETs I have and get some on there.

A question now...  You say that R7 may control the amount of octave in the circuit.  Maybe I can use a pot as a variable resistor there?  Would that control the amount of octave?  Whats a good value to use (maybe 10k or so)?

[RaceDriver205]

Sound clip? I don't think theres one on the site, and I can't check coz its down.

[KerryF]

I will get soundclips up today, but do you think that lowering the value of R7 will allow more octave?

[KerryF]

I tried to modify R7 to 10k and 15k and they dont let more Octave through.  Anyone else have an idea of a place to change the value to allow more octave through?  I really want some good octave in this pedal and cant seem to get as much as I want.