My first post.. and second project -> Kay FuzzTone Clone

[rikkards]

Hey all!
I have been lurking for a while and finally decided on a second project (the first was the booster on this site which was a good warm-up). My decision was a clone of the Kay FuzzTone pedal as one of the songs I play frequently is Elevation and my GT-6 doesn't do it justice. So I bought the wah enclosure from SmallBear and once it got here after Canadian Customs took their sweet time I got to put it together. I got the schematic from here but had to do some substitutions (NTE199 rather than Transistors listed) as I couldn't find a source for the 2sc644s or 2sc945 without buying a bajillion. Also I changed the pot to a 200K with a 47k resistor following from the 250K and it didn't seem to change the tone compared to a 250K I tried (the 200K was the wah pot I got from Small Bear I ordered as I didn't realize it came with the gear in the enclosure (could have asked but didn't). 

If anyone is interested here is the layout I used in the placement software from here
And here is the guts shot
I incorporated True Bypass and power off when cable not plugged in as well as an LED (right side of case.
Seems like a reasonable rendition of it but I need to play with the GT-6 EQ to get it tweaked but it may also be my amp as it is a 63 Bassman rather than an AC30. It is missing something though that I just can't put my finger on...
This board has been really helpful and I appreciate all the informative posts that I was able to read as they definitely gave me some assistance and ideas.

Next up: Foxx Tone Machine and a Fuzz Face.

Otherwise Comments, critiques welcome!
Thanks
Chris

[8mileshigh]

Chris,

Very cool, I was just researching this project Friday and wondered where I was going to get a Wah enclosure, I didn't know Steve sells them.  You can use regular 2n3904 and 2n5088 transistors in there from what I read at another site. 

A year or so ago, somebody here built a scrambler wah or expression pedal that sounded killer, I'd like to build something like that too.

Chris

[rikkards]

Thanks for the reply!
If you look a bit down his page, you will see "Wah Wah and Swell Pedal Parts"  which is where I found it. I originally looked on Ebay for a dead one but no luck. It comes with the feet, back, the pinion gear (or is that rack?), the enclosure. The only things it was missing were, the switch, the battery, the pot, and the circuit. Also has 1 hole on the right side for a jack and two on the left.
P.S here is the link

I tried a 2N3904 and it sounded pretty much the same. I am wondering if it may be the diodes as I originally had some Radio Shack Germanium diodes in and changed them with the NOS ones I bought from Small Bear. I think the sound changed course it could be my imagination maybe I will post an mp3 at some point.

Also I forgot to mention, in the layout diagram there is a break between the Bases of Q3 and Q4 which game me no grief.

[8mileshigh]

Hey Chris,

I found a layout here http://www.ustomp.com.  Looks like he build a stopmbox version.  I'd like to hear some sound clips when you get a chance.

Chris

[rikkards]

I looked at his schematic and he had done the opposite of what I had done which was use a 50K pot with a 200M resistor while I used a 200M pot and a 47K resistor. I think it doesn't really matter what the pot is as the most noticable change in the tone is probably from 200-250M. which is where the pot is set for. With mine, I noticed that if you set the pedal to fully down and have the pot connected at completely to the right (250M), it will only turn about a 1/4-2/3 of the way when rocking it back before hitting the other end of the pedal. You never get down to 0M but if you did, it essentially shorts out thus cuts off the signal.

I am trying to think of how to describe the difference in sound compared to the recordings I have. I have three different versions of Elevation (Album, Slane Castle and Vertigo tour) and I think the closest sounding is Slane Castle's. Assuming he is using the exact same pedal in all three it may be how the recording was miked or processing in the studio, the other equipment used (Vox AC30 vs 63 Blonde Bassman) or just component differences since mine was all new.  I did try some 3904s when prototyping it and it didn't make much of a difference at all.

I think I will try to make a couple mp3s without my board and maybe through the AC30 simulator and clean through the GT6. I wonder if the transistor differences would make a significant difference in what I am hearing or could it be the diodes (or even worse my ear)? Most likely a combination of all of the above. I am hoping that some playing with the EQ settings on the GT6 may help.

Now I need to see if I have the appropriate cabling to record it.
Any idea of a good site I can host it on?

[rikkards]

Ok here is a really quick and raw sample of it. Not my best work either but then again I never said I was really any good


The setup is my Epiphone Les Paul into the pedal then using a cheap cord straight into the line in on my SB Audigy sound card
straightin.mp3 - 0.51MB

The next is the LP into the Boss GT-6 with no amp emulation
processed.mp3 - 0.57MB

The last is the same as processed but using the Vox Clean Amp Emulator with a 1x12 cabinet. (not much of a difference if you ask me but...)
vox.mp3 - 0.37MB

I think I am getting there but it sounds kind of more wah-ish then you would expect. Now the question is what do you think could be changed (diodes?) to get it closer or is there really no point?

[8mileshigh]

Chris,

Have a listen to this clone.  [url][http://youtube.com/watch?v=kUgH0VEMtHI/url].  Your clone is missing gain and sounds like a mild fuzz, what's the gain of the transistors you used ?  Try using the 2n5088's in there, maybe it will give it some more attitude.   I'll send you some if you don't have any handy..

Chris

[rikkards]

I was thinking the fuzz seemed a bit lacking or "thin" but I thought that was just me.

I used all NTE199s which were readily available at the local electronics store. Looking at the following links, it should (key word "Should") be a direct replacement for the ones in the schematic:
2n5088
NTE199
Maybe I should try doing the hfe calculation on these and see if they really are what they are speced at. The other thing is I wonder if something isn't quite working right in the circuit...
I have an existing order in with SmallBear, may see if he can throw in some 5088s with it before shipping.
Thanks for the advice.

[rikkards]

Looking further into the spec sheets of the 5088 vs the NTE199, the NTE is rated up to 50V while the 5088 is only 35V. Most of the specs otherwise are really close. Maybe this is related to the weak fuzz?

[g3rmanium]

I found a layout here http://www.ustomp.com.

Wasn't that layout different that this one that was discussed in this thread?

[rikkards]

I found a layout here http://www.ustomp.com.

Wasn't that layout different that this one that was discussed in this thread?

The big difference with the ustomp one compared to the one I used was was a change of the R10 which is a 10K on Johannes to a 100k  on the ustomp. I am wondering what will happen if I change the 10K in the collector with a 100k resistor? I would assume the voltage drop across the R10 would increase? I figure the transistor will go into saturation? This a good thing?