Fuzz Face SI Transitor advice please

[Bret608]

I also have a Blues Jr. on which I did the BillM mods. It's never met a fuzz it didn't like honestly. I built a hybrid Fuzz Face on vero (Ge Q1; Si Q2) and the sustain is really long, with no weird die-off. The cleanup with the volume knob is also pretty good.

[somnif]

Digging into the world of low-gain SMD options has been... oof.

In terms of direct, drop in replacements for thru-hole options, surprisingly the 2n2369 has been the easiest. Nexperia makes a direct copy in SOT-23 (PMBT2369).

So that's the whimpy low gain Q1 taken care of.

Q2 (and/or Q3 if in tonebender country) is trickier. The BD139 DOES have an SMD equiv, but its in a goofy package (SOT-223/SOT-89).

And trying to figure out where other transistors fall is... tricky. Oh, sure, this component has a gain range of 10 to 900. That's bloody useful.

FMMT619, BCW65A, BCW66G, a few hundred seemingly randomly named Toshiba 2SC varieties, etc etc etc.

My best bet so far is "2PD602AQL", hfe range of 85-170 . But that's assuming I'm not missing something glaringly obvious in the datasheets.

I need a shovel for all these datasheets. 

[somnif]

Well, just opened Arrow.... and ended up buying 18 different varieties of SMD transistors to play with (oops).

But that should cover the gamut from the axis face's sub-100 q1, to Eric Johnson's over 800 q2 and many points in between.

I really need to figure out an easy way to test the hfe's of these things. And breadboard options and combinations....

[Flying]

I'm beginning to understand the fascination with the Fuzz Face, I came to it out of a curiosity and with the hope of recreating a couple of tones, but I'm now in a phase of being totally intrigued by it, frustrated with it and captivated by range of the tones and how it reacts to the pick attack and volume knob!

I've been playing around with a straight fuzz face circuit as the beginning point and swapping out transistors, input and output caps and output volume pot, so far I have determined I need about 3 of these as I've yet to stumble upon the holy grail combination.

My amp is not the most traditional, Yamaha THR10C, but it's really the only option currently as I need to keep the overall volume level down, so my aim is to see what I can put together that will work happily with that amp. Generally it takes pedals very well, but I appreciate the fuzz face is picky about what's either side f it.

Anyway, more experimenting to do.

[somnif]

Yeah my only amp is a Fender Mustang practice amp. Hooray dirt cheap "totally accurate modeling" cough cough....

Yeah I'm used to things sounding thin and whimpy and half-dead on the thing. But alas my apartment has thin walls, and thus I must be a headphone player.

[jalmonsalmon]

You really need a dimed plexi amp and toss a FF in front... then the magic begins    Just ask the axis

[jalmonsalmon]

Yeah my only amp is a Fender Mustang practice amp. Hooray dirt cheap "totally accurate modeling" cough cough....

Yeah I'm used to things sounding thin and whimpy and half-dead on the thing. But alas my apartment has thin walls, and thus I must be a headphone player.

Seriously... I think for your type of thing I would look into a wampler velvet fuzz clone... it would more or less do what you want in the headphones...   

[somnif]

Oh god help me I forgot how ridiculously tiny SMD stuff is. My shakey hands are not going to cooperate with these 0603 grains of sand.

[Flying]

New transistors have just arrived... I seem to be going for bigger components not smaller 

[somnif]

My ugly as sin OSHPark version of Pickdropper's NoMoJo fuzz (kludged with permission). Vias too big, pot pads too small, and screenprinting a complete gamble as to where it would show up, an utter travesty! My sincere apologies to your engineering prowess kind sir.

And now to test!  ...erm, after I wait on Tayda for a trimmer I thought I had in stock, grumble grumble grumble. Oh well good excuse to restock on pots.

And oh god I am so bad at SMD. Only sacrificed 2 resistors to the carpet gods, but that was a close run thing. (Also realizing I should've done the back side of the board first since that big old filter cap is going to make things awkward as heck)

[pickdropper]

My ugly as sin OSHPark version of Pickdropper's NoMoJo fuzz (kludged with permission). Vias too big, pot pads too small, and screenprinting a complete gamble as to where it would show up, an utter travesty! My sincere apologies to your engineering prowess kind sir.

And now to test!  ...erm, after I wait on Tayda for a trimmer I thought I had in stock, grumble grumble grumble. Oh well good excuse to restock on pots.

And oh god I am so bad at SMD. Only sacrificed 2 resistors to the carpet gods, but that was a close run thing. (Also realizing I should've done the back side of the board first since that big old filter cap is going to make things awkward as heck)

I would add a bit of flux and reflow those joints.  It will probably look significantly better after that.

[somnif]

I would add a bit of flux and reflow those joints.  It will probably look significantly better after that.

Erm, yeah, that's after flux and reflowing (and reworking, in a couple cases) 

(also, funny enough 99% isopropyl cleans most of the flux away but not the big skid marks. Wonder if the flux in my wick braid is some oddball formula)

I really need to buy some thin-guage solder if I'm going to do much SMD work. The tiniest touch results in big gobs of it flowing in this case (and my shakey hands don't help)

[pickdropper]

I would add a bit of flux and reflow those joints.  It will probably look significantly better after that.

Erm, yeah, that's after flux and reflowing (and reworking, in a couple cases) 

(also, funny enough 99% isopropyl cleans most of the flux away but not the big skid marks. Wonder if the flux in my wick braid is some oddball formula)

I really need to buy some thin-guage solder if I'm going to do much SMD work. The tiniest touch results in big gobs of it flowing in this case (and my shakey hands don't help)

Yeah, thin gauge helps.  I have 0.015" stuff that I use for that, although 0.020" is generally fine as well.