pinkjimiphoton' photon phuzz

[Marcos - Munky]

Some time ago, Jimi suggested me to build his Photon Phuzz. Here's the schematic:
https://guitarpcb.com/wp-content/uploads/2018/06/BD_Photon-Phuzz.pdf

So I drew a layout for a 1590A, got an BC108 transistor and gave it a try. It's a very simple build, but it sounds amazing! The bias pot really does have to be a pot and not a trimpot. At one end, I got a splatty fuzz (but not too splatty). The notes gated as they decay. An interesting fuzz sound. As I keep turning the bias pot, I got a nice balance of notes not gating and splatty fuzz.

After some point, the sound starts to get some bits of a overdrive sound. At almost the other end of the bias pot, I got a really nice tube-like overdrive, excellent for lead and chords playing. And it responds very well to pick dynamics and guitar volume pot.

Also, I did a quick test with an harmonica and it sounds great!

Here's some photos of my build. For the artwork, I used a picture of another Jimi, painted in pink as a reference to Pink Jimi . Used pink knobs that sadly didn't exactly matched the artwork color, but I liked it anyway.

[brianq]

No "stupid pedal trick"? I'd like to hear it jimi

[thermionix]

Looks like a breadboard candidate.  Any particular transistor specs?  I guess I mean especially if I were to try Ge.

[thermionix]

No "stupid pedal trick"? I'd like to hear it jimi

[brianq]

Kool,it must be nice to have somebody who likes your circuits enough to manufacture them?

[Marcos - Munky]

Looks like a breadboard candidate.  Any particular transistor specs?  I guess I mean especially if I were to try Ge.

Well, Jimi told me "use what you have". His favorite one is a ge transistor, but I didn't asked for specs. I guess the bias pot makes a lot of transistors usable and good sounding. I used a BC108 I had here which honestly I didn't checked for specs, but I plan to build a ge one after I finish some projects.

[thermionix]

Looks like a breadboard candidate.  Any particular transistor specs?  I guess I mean especially if I were to try Ge.

Well, Jimi told me "use what you have". His favorite one is a ge transistor, but I didn't asked for specs. I guess the bias pot makes a lot of transistors usable and good sounding. I used a BC108 I had here which honestly I didn't checked for specs, but I plan to build a ge one after I finish some projects.

I looked again at the build document, and they say hFE range of 100 to 400 should work.  I suppose since this runs well with Si, then Ge leakage is probably best kept low.  I can't breadboard it now anyway, as I don't think I have that zener diode.  I assume it's there for asymmetrical clipping, and needs to be the right voltage.

[Marcos - Munky]

I didn't used that exact zener - well, I do used a 9V1 zener, but mine is a half watt one and the one used in the build doc is a 1W one, not that it makes any difference in this circuit. Jimi told me the zener is his 1st choice for this circuit, but a led is a 2nd choice for the clipping, I just don't remember which color because I always delete the old messages in a conversation.

Btw where's Jimi? He can answer those questions when he sees this topic. But he told me to just use what I have in hand for the transistor and the diode.

[thermionix]

I didn't look up the zener before posting, I was assuming it was something considerably lower than 9.1V, to clip both ways somewhat asymmetrically.  But if it can be replaced with a single LED, well that's more asymmetric than I was expecting.  I might actually have a 9.1V, will look into it tomorrow.

[pinkjimiphoton]

awww, thanks for the props, Marcos
sorry, been busy... summertime means too many gigs, too much debauchery, and more important, painting guitars on the rare days i could get away with it over the summer.
here's why i haven't been around:









i built this one up from a 59$ destroyed hush from guitarfetish, which is local to me <well, an hour away>>.... also built pink paisley strat and tele, and a flying v <flyin weenie> and a couple other things... so no time for pedal work, which i regret immensley. its just too damn hot in my dungeon in the summer time. my glasses fog up.

anyways... questions... this was labeled photon phuzz by barry at guitarpcb, but thats actually a completely unrelated circuit.

the one in the video above is the guitarpcb one tho, so should give ya an idea. it has a bc108 or 109 in it. i forget which.
ANY @#$%ing transistor should work, from leaky ass low gain ge to darlingtons. socket and swap til ya feel a little wiggle down there.
i prefer npn ge, but like i said anything will work. i've used it with si, ge, even some jfets will fire in it. mpsa13 and 18 work, too, tho its a lot gnarlier and in some cases things WON't work... so socket and see.  if ya find a ge and an si you like, just solder their e's and c's together, and use a switch to swab which base is being used for input. stupid simple, no pop cuz the transistor seems to absorb the transients.

the biasing is weird. there really isn't much, with ge its for all intents self biasing from leakage. the diode can be anything, pretty much. i spec a 5.1v zener i think, but i've used 1n400X, led's, even a mosfet. pretty much anything should work. i think the distortion character is better with a lower rated zener, to my ear, the 5.1v sounded best so that was what i went with, but truthfully anything should work fine.

barry <my7of9> at guitarpcb.com has these boards for sale for 5 bux or so, which is a decent deal. he often throws in the proper diode and q etc as a bundle with it. he is using it by my permission, which i thought was really cool after tonereport stealing the suzy q circuit verbatim and then being douches about it after the fact.
i don't make any money off it, nor do i ask for any.... i am glad to help barry earn money to raise his wonderful kids. he works hard as mom n dad for them, which gets huge respect points from me having been a single dad myself with three kids.

the bias knob is crucial, as munky said... its where all the tones come from, and there's a lot of them. for all intents, the q is biased wide open, so whatever ya put into it gets amplified hard and results in a lot of second harmonic... this is related to my ancient prophet and monkey balls projects too... the ancient prophet is 3 of this in series, and the monkey balls is two stages with a FAL treble booster for a front end.

you can go with a bigger bias pot, too, which may result in more useful transistors, but i found bigger or smaller didn't give a very useful sweep.

originally when released <stupid simple overdrive> it didn't even have a volume knob, i designed it to just sweep to the sweet spot, then use your guitar volume to control it.
it gives a nice tubey od to mild fuzz and just a little bit of boost too, so the volume pot was a natural addition.

thanks for checking it out marcos!
i hope anybody who builds it diggsit. if ya need a vero, let me know, i think i have one kicking around... or ask munky for the project files, or better yet, support my bro and buy a pcb from guitarpcb.com.

thanks everybody... rock on, and much love to all

[brianq]

Beautiful guitars Jimi, I'd Shanghai those in a hot second!!!!!!

[pinkjimiphoton]

hahah thanks bri, i'll be sure to keep 'em locked up if ya come to visit

shoot, dude, you can learn to roll your own. i did, so can't be THAT hard.

[brianq]

Definitely, I've built plenty of my own too

[bluebunny]

Well, as mitigation for not building pedals, those axes are a fine excuse.