Building the Christine oscillating fuzz PCB

[frequencycentral]

Hell, I'd buy dogsh*t from him, but my dog's got that covered.

@ Taylor. I don't own a dog. Can you help me out?

[Taylor]

Sadly, I haven't a dog myself these days. I'm a big dog fan, much more than I am a fan of most animals including humans, but my landlord won't allow them. All I have is my ladyfriend's horrible cat, whom I despise. It has been known to produce waste from time to time, not sure how to mark that on the customs form though. Insert joke about "duty fees"

I'm preferring the extra gain in the front end, as opposed to an external boost, as I can get more oscillation control with my guitar's tone knob this way. Almost like a $10,000 guitar with a fuzz factory built right into it... imagine if somebody had such a thing.

[bassesofdeath]

Diplomatic salesman... I like that. Going to order the PCB today. The controllability factor is important, since often times I need to be able to tune the oscillations to a certain key.

Will using ceramic caps make a big difference here, or do I need to order those box types, like you've got there?

I'm wondering the same thing as well. Are there other capacitors that may be used safely, when boxed metal caps are not available?

[Taylor]

Yep, as the build PDf says:

[cap types are only suggestions for what works and fits properly on the board. If you prefer something else and know
what you're doing, feel free to substitute]

Don't mess around with the electrolytics.

But for the others, you can use any non-polar cap type, and I don't think you'll hear any difference, especially in a circuit as chaotic as this one. People argue endlessly about whether different cap types sound different so I won't go into that here, but you won't break anything by using ceramic or some other kind of film cap where the PDF calls for boxed film.

[digi2t]

Sadly, I haven't a dog myself these days. I'm a big dog fan, much more than I am a fan of most animals including humans, but my landlord won't allow them. All I have is my ladyfriend's horrible cat, whom I despise. It has been known to produce waste from time to time, not sure how to mark that on the customs form though. Insert joke about "duty fees"

Gift??? 

Get yourself a Westie. Not even the coldest, scroogiest, curmudgen of a landlord could refuse a Westie. If he does... well, you must live in hell then.



Oh yeah, that's right, your girlfriend's got a cat. Yup. You're in hell! 

[PereatMundus]

Finally pushed it into the case.

Its an insanely tight fit, but it works. Im still cutting down wires to make the fit as good as possible.
(the PCB is exactly the width of a 1590A so you gotta  cut out slots in the bottom cap sides to make it fit correctly)

[PereatMundus]

Sealed the slight overlap with  self vulcanizing rubber

Gut's needs overhaul, the problem isnt in so many pots on so little area but rather, all that damned wireing.

[Taylor]

Wow, that's completely insane. Awesome work! I also like that the piece of cardboard separating the jacks seems to read "R G". 

[PereatMundus]

Wow, that's completely insane. Awesome work! I also like that the piece of cardboard separating the jacks seems to read "R G".  

thanks my first tiny-build that is. Need to shorten some of the wireing to make a better fit eventually, and switch out that eye-burning led. other then that it all works well
the "R G" thing is piece of a plastic "Crew IDcard" for some Industrial-Metal/EBM gig's I organised, needed something in there to keep the jack-tips apart, and it was on the desk at the time.

[digi2t]

Hey Taylor,

Can I throw a switch in between lugs 2 and 3 of the power starve pot, so I can cut the starve in and out? Something like the Parallel Universe II starve switch. OFF (bypass), it jumps 2 direct to 3, and ON it disconnects 2 and 3 allowing for the pot resistance to dictate the power to ground. What do you think.

I kind of like having that function on the PU, because I can dial in a sound in starve mode, and kick it in and out.

Cheers,
Dino

[digi2t]

Well, I've put it together. As always, top notch board Taylor. I just find that maybe the 1M pot for the oscillator may be too big (on mine, anyways). It seems that all the action is in the first 1/3 of a turn, after that, mucho of the same little girls gettin' their pigtails pulled  . I'm wondering if a smaller pot may be in order here, to widen up the range. Also, I reversed the wires on lugs 1 and 3 on same, because I found it counter-intuitive when dialing in noise.

Buffered chip is just pure chaos!! I'll stick with the tamer version.

Cheers,
Dino

[Taylor]

I sometimes find that the CCW range of the OSC pot does some interesting things with the power down, tone to bassy - in other words, sometimes it acts like you say, but depending on the other knobs' positions, it has more range. But it wouldn't hurt anything to use a smaller pot and you probably would get a little more tweakability for the most part.

Sorry I didn't catch your earlier question about the starve - a switch for that function sounds like a good idea to me. A stomp switch would be pretty useful.

[Processaurus]

Those look like really good, compact, easy to assemble pcbs, Taylor!  I'm imagining a 1790bb box with 2 of them in it, with some wacky switching and mixing like this idea.

[Taylor]

Thanks Ben, that sounds like a cool idea. 2 of these in parallel would be madness.  

[thedefog]

Hey Taylor,

Got your board on Saturday and populated it. Nice layout! Was a cinch to build. Thanks so much! Unfortunately I made the newbie mistake of stuffing it into the enclosure before testing it out. I'm getting a real nasty hum that I have to debug now. I used some really crappy thin ribbon wire to connect the pots that I'm pretty sure is the culprit. That, or I have a pot lug/wire touching the enclosure somewhere as it crackles when I wiggle stuff. I'm also using the millenium bypass instead of a 3pdt so lots of possibilities. Bleh... But my weekend wasn't a total failure, at least I got my TR-606 working again with MIDI and kick/snare mod pots installed and finally beat Dead Space 2 on Zealot difficulty. 

[ckyvick]

When I adjust the tone pot it cuts out the signal and fades back in at the new setting. Could I have a bad tone pot? The pedal worked for about five minutes then just cut out completely
Here's a pic of the finish, went with a 125b so I could fit a battery. Says "Insano Fuzz" on the bottom

Also, if I turn the power down and then turn it back to max while testing the ohms with my dmm it goes up to 60k or so then slowly increases, is that normal? This is with no power in bypass and the pot still in the circuit.

[Taylor]

The tone pot does act like that - if you make a drastic change the sound will fade out and then fade back in. Not sure why that is, but it's happened every time I built this circuit. I don't find it to be a problem, kind of an interesting quirk.

You generally can't measure pots or resistors accurately while in circuit. There will always be other series or parallel impedances which make the pots read some strange value.

But now you can't get it to make any sound no matter how you set the knobs? I suppose the normal debugging routine will be the next step.

[ckyvick]

Ok I have a clean signal coming through. Volume works-ish, gain acts as a secondary volume knob, tone cuts out but now does not change the tone(acts like it is fully cw to the treble side), osc does nothing, and power seems to work. It pops when stomping the switch and is a little quieter than bypass.
Volume works until maxed, then it turns into an oscillating low rumble that doesnt stop, with this the tone knob cuts the guitar back in for a second when it is turned ccw at any point in the rotation, and power has this same reaction but only at the very end of the sweep when turned fully ccw.
Any ideas where I should start looking? Thanks!

[Taylor]

Which chip are you using?

[ckyvick]

It's a cd4049ube from mammoth.