Ever played an original FuzzFace from around 1970? (HINT: Not AT ALL the same sound as ones with the same namesake being mass-produced currently.) Ours has two intentionally mismatched (for harmonic content) silicon transistors that snarl and spit... not for the meek! If you put the "Fuzz" on 10 you will rip, and you might get all sorts of oscillation and weirdness... but that's Rock. Don't try using it with a wah wah... you can't, and neither could Jimi, without it screaming and howling. You want polite and quiet? Go elsewhere. You want art in a box? Come on in.
Housed in a 16 gauge steel box and powder coated deep blue, this pedal is a bit unruly but with some warmth... ideal for older 4 input Marshall amps, it has much more FUZZ than the '69 Pedal and includes a Mid control for extra clarity and cut.
I got my hands on Eric Johnson's Blue Fuzzface that he used from Tones through Ah Via Musicom period (now owned by Ian Moore) and incorporated a few of its tonal secrets into the '70 pedal with staggering sonic results!
Product Updates:
In December 2009, after 15 years of production, the 70 was discontinued. However, I recently found/bought a couple thouusand excellent BC108C transistors, so am happy to announce the return of the 70 pedal... this time, in a small (OCD-sized) housing. These transistors sound outrageous! This model 70-BC still has the secret-weapon "Mid" knob which will allow you to do something other Fuzzfaces won't let you do.... be heard in the mix. ;)
Any good BC108 replacements?
ReplyDeleteMost medium gain silicon NPN transistors should do. I'm probably going to build this with a 2SC1815 and a BC550B.
DeleteThank you! Any diode replacement? I've got a bunch of 1N4148 and 1n4007
DeleteThe 1N4148 is exactly the same as the 1N914 so no worries there, as a replacement for the germanium diode I'm not sure. It will certainly work but I would expect the response to be somewhat different. Basically give it a try with the 1N4148 and see what you think.
DeleteCurses. I laid the components out on my desk, warmed the iron up.. I'm all out of vero. I'll be tackling this one tomorrow.
ReplyDeleteAny idea as to what the diodes do?
This is what Clay Jones wrote about it on FSB a few years ago and he's considerably more clever about these things than I am!
Delete"At dc the diode placement is irrelevant. At Q1 the reverse bias just sets the thing at a (perfect world) infinite resistance. Open. It couldn't care less at dc. Q2 forward biases in the same old same old shunt clipper way...just slightly varying the operating point. Blah.
At ac the the diode placement is trivial. Any negitive swing at Q1 just ignores the thing, like it wasn't even there. Like it was just one big damned resistor. It moves on down the line. The upswing is only impacted providing that the gain at that point is enough to send the diode into conduction. That's the reason for jamming the diode's anode into the junction at the emitter pot wiper and the bypass cap. It's just taking advantage of the gain characteristics of the bog standard FF setup rather than limiting that section by strapping it straight to ground. Any positive signal level less than the forward conduction magnitude of the diode just goes on it's merry way flapping against the base. In that case, both signal sides flap away like any other entry level transistor amp. The diode may as well not be there. Any upswing signal that sends the diode into conduction will chop the top like any run of the mill clipper clipping at whatever level it clips. Again, same old same old. The bandwidth gets flattened and broadened, the rolloff point gets lowered and earlier frequency 2nd order harmonics crash up against the break point etc. etc. and all that other mystic shit that happens at clip levels...
Q2... meh, again. Reversed biased negative swings couldn't care less. Forward biased positive swings clip at a slightly altered operating point, riding above the threshold to ground level. pfft. The whole thing is an assym clip with an approximation toward "symmetry" happening at higher input levels. Push harder at the input and vary what you might call the transconductance characteristics. A typical FF does this anyway. This is just some doinking crap mod which creates barely noticable alterations in the operating points. I say barely noticable... sure, whatever. It's enough apparently to send the TGP type crowds into orgasmic circle jerking ecstacys of self congratulating patheticisms of how great each other's "ears for tone" are. No doubt in my mind either that there's [self edit to tone it down some...]
Uhh... yeah, sure. Nothing special really... just another slightly modded FF."
......eh!?
DeleteI sort of get it. I expected it to be more of an "intentional mismatch device", creating an extra voltage drop across the diode (explaining the mixing of Ge and Si)... but it's just wankery at the end of the day (which Fulltone's not lacking in!)
DeleteWhich transistor should be the higher-gain one (left or right)? I'm a bit confused.
I know Mark, beats the fuck out of me! :o)
DeleteAnd Ross, I didn't use the transistor symbol with the BC108Cs having the triangular pin layout (and so any pin configuration is easy to match on the board by just rotating it) but I forgot to mark out which was which. The bottom transistor is Q1, and that should be the lower gain one as per the usual Fuzz Face selections.
One other thing before anyone mentions it, the Fulltone 70 schematic has a 1M pulldown resistor from the volume pot output which I have omitted because I can't see the point of it when the pot is performing exactly the same task. All it achieves IMO is adding a 1M resistor in parallel with whatever the volume pot is set to, and so when at full volume for instance the 1M is put entirely in parallel with the 250K pot, which just gives you a 200K pot with a slightly weirder taper.
ReplyDeleteIf you really want to include it, just solder a 1M resistor between lugs 1 and 2 of the volume pot, but I don't think I'd bother.
You can call this one. It sounded great in my initial late-night-quiet-so- the-family-doesn't-wake-up test. I ended up using the 2SC1815 / BC550 trans combo suggested by Ross. I didn't have a 1KC so I used a 1KB and all the fuzz is in the last 5% of rotation. I will replace that one for sure.
ReplyDeleteNice and quick verification, thanks mate, and you too Jon :o)
DeleteI can Second this Build. I noticed on the BC108 Data Sheet BC107 & BC109 are similiar. I used BC109. Also it is Best with your favourite Booster Pedal in front of it to get all the Radical Fuzz Sounds. Also note the legs of one of the transitors is Crossed ie ECB instead of EBC. I also just used 1K B instead of 1K C for the Fuzz Pot. Thanks again Mark for putting up this Pedal. Much Appreciated.
ReplyDeleteLooks like fun! Any ideas of hfe a I should be looking at?
ReplyDeleteCheers
Hi, Mark! Fuzz work with BC108B?
ReplyDeleteYes they're just lower gain
DeleteThanks!
DeleteHi mate, I just finished building this and I've gotta say....wow! I ended up using a 2n2222a for q1 hfe 200, and a bc109c for q2 hfe 420. Sounds great. I've got an original fulltone 69 at home and this 70 rips it to shreds. I guess I like my fuzzface with a sprinkle of silicon. Thanks for your awesomeness!
ReplyDeleteGreat info, thanks for that Jeff and glad you like the build
DeleteI've built this as well... 2N3904 in Q1 and 2SC1815 in Q2 does not work well at all. I'm going to run out and grab the equivalent to a BC183 today, as that worked quite nicely with my Meathead. From what I've heard, this one's a bit darker and dare I say a bit more polite than the Meathead, which is probably my favorite FF-style pedal.
ReplyDeleteMaybe this was asked before and i overread it... but do you need to match the BC108c's or check them for the right hfe values/leakage currents etc?
ReplyDeleteOr should any stock BC108c hfe 400-800 do?
I've just built this and no matter how many transistor i change...sound just the same!!
ReplyDeleteBc108 a-b-c ,2n2222a, Ac/dc Adsl ,ZZTOP, U.s.a, U.s.s.r etc etc...It sound the same...super higain...
and if i lower the gain or the guitar volume pot sound terrible.
Obviously something got wrong...any suggestion?
Ohhh i forgot...Mid Pot does have no effect
ReplyDeletejust built this one last night with two BC109C's. it sounds great. I also added a 'bias' (B50K) pot on the input borrowed from the '69 so I can get a little brighter tones when the the fuzz knob is at lower settings.
ReplyDeletegot mine completed and boxed. it sounds awesome. here's a pic of it.
ReplyDeletehttp://johnkvintageguitars.homestead.com/Effects/Fulltone/70/70pedal-01.jpg
I also own an original early, large box version of fulltone '70 and I gotta say that I like my clone a lot better than the original, mostly due to the added 'bias' (input attenuation) control.
Awesome!!
DeleteIs that hamertone-paint or powder coating?
I'm also very interested to know how you got the white graphics on there since i had about the same idea for a box.
I normally use waterslide decals and i can't print white on them :(
(Great site by the way)
I never get my hammertone finishes (spray or paint) that nice. I'm jealous :)
Deleteit's a powder coated enclosure. the graphics were done with a p-touch labeler.
DeleteI just tried an NPN germanium in Q1 (with an hfe of 242), with a BC109C in Q2 (hfe of 520), and I like it even better now.
ReplyDeleteI've just got all the components together to built this one. Just one question:
ReplyDeleteIn the schematics i found the 2u2 cap is a 22u cap.
Not that i'm not gonna try both, but what should be the overall difference?
As a matter of fact... there are also some differences in the area around the MIDs pot (1K and 220R) and the 47u which is missing. Makes me think i haven't found the correct corresponding schematic :S
ReplyDeleteMIDs pot area thing solved!
DeleteThe order of the 220R and the 1K pot parallel to the 1K is reversed in my schematic but should result in the same resistance.
:)
Can you send me a link to the schematic you're doing it from. I did it from this one:
DeleteFULLTONE70CORRECTED.jpg
Thanks,
DeleteI think i had the UNcorrected version of this one :)
Is the 3rd lug on the mid pot not supposed to be connected to ground or something? I've built this circuit twice and I'm still having trouble with it. I get hiss when I turn the mid pot, but otherwise no sound when the effect is engaged. I've check and rechecked and I'm fairly positive that everything else is correct, but I suppose I could be missing something.
ReplyDeleteNo, if it was supposed to be connected to ground it would have been shown on the layout. It's being used as a simple variable resistor so only 2 lugs are used.
DeleteI guess some times you just have to walk away, pour a glass of scotch, and come back to it. I misplaced on of the leads on the 22uf cap. It's a little late for me to really take it through it's paces at the moment, but from what I can hear I'm really digging it! I used these bc108s from small bear and it sounds great!!
Deletehttp://www.smallbearelec.com/servlet/Detail?no=1199
I haven't amassed a huge stock yet, but I have a few other NPN transistors lying around and I'm really stoked to swap them in tomorrow and see how it sounds.
I'm really happy with this pedal for the most part, but I'd like to brighten it up a little. Could I do this by swapping out the 100n cap for a lower value? 47n maybe? Or could I possible change the mids pot for another value? It's maxed out and still sounds a tad bass heavy to my ears.
DeleteGot it on breadboard right now. i Think it sounds the way it's supposed to :) Anyway it sounds great to me.
ReplyDeleteBy the way, I have connected lugs 2 en 3 of the Mids pot.