multi face problems

[b_rogers]

first time poster here..i built the multi face with 2n3906 trannies and the sound is terrible...really splatty...not really much gain either, no matter where i set the trim pot. are there any transistors from radio shack that will sound better? 3906 was the only # i recognized. i was under the assumtion the silicon would be really fuzzy but all i get is crackly splat or really clean...it does clean up well with my strat..but sounds terrible over all. please help as i wanna wow my buddy tomorrow with my first effect.

thanks a lot
Brent

[bwanasonic]

I think you need NPNs, which would be the 2N3904. Not sure that will sound great either but... If you are limited to RS parts thats about it. The Multi-Face article at www.runoffgroove.com  has suggestions on trannies.

Kerry M

[b_rogers]

will npns sound different? i know i had to reverse my battery and cap polarity...i saw the 3904 i will pick up a few of those ...thanks for the help

[ErikMiller]

It's an easier build with 2N3904's, although I don't care for the way they (and their sibling the 2N3906) distort.

With Fuzz Faces, always be sure to check the voltage on the collector of Q2. You want something close to 4.5V.

[b_rogers]

are the 3904 any higher gain?

[petemoore]

I believe 3906 is the pnp equivalent of the 3904.
 You mihgt like trying a lower gain NTE123, 2n2222a etc in Q1 position.
 The multi face IIRC allows you to use many different types of trannies...
as long as you have the ckt setup for NPN OR pnp, and use the appropriate transistor [npn OR pnp].
 The only reason I ever built pnp FF type ckts is to use the pnp Ge transistors that are available.
 Try some Germanium transistors in there...a matched set from Small Bear is hard to beat. I just ordering a FF set and TB MKII Pro set [as soon as paypal gets back online].
 It sounds to me like a gating problem caused by misbiased transistors...
do that DMM [VM] check of Q2's collector voltage and adjust Q2 collector resistor accordingly [I always socket that Q2 collector resistor or use a trimpot, a trimpot makes it easy to properly set different biases to try out different transistors]. For [almost] every tranny swap the collector resistor [or preferable trimpot on a multi face] should be adjusted or checked. Shoot for 4.5v on Q2 collector, sometimes I like a little more say up to just over 5v. I tune this trimpot by ear, then check the voltage on Q2's C.

[D Wagner]

are the 3904 any higher gain?

The 2N3904 is the NPN compliment to the PNP 2N3906, and they have the same gain, (per the data sheets).

If you are looking for a high gain NPN transistor that (IMO) sounds great in a Fuzz Face type circuit, go for a pair of 2N5088's, or 2N5089's.  

I socketed my FF's and tried a lot of different transistors, in pairs and mixing and matching  low and high gain transistors.  In the end, I found that two really hot 2N5088's sounded best to me.  The friend that received the FF liked it a lot, too.  So much in fact, that it is his only fuzz!  

Transistors are cheap.....experiment!

Derek

[b_rogers]

ok now i think something is wrong with the q1 cuircut..it just wont really distort..its either clean or splatty...i got 2n2222 and tried that..still no improvment..tried 3904..aargh i think i am gonna rewire it and see if that helps..

[petemoore]

I build another...I've had these things where I don't know what's up...probably a wiring error or who knows/ bad cap?
 I figure the time vs money warrants another try on verified ckts...I think the FF classifies as verified...lol
 re- check all the colors on your resistors. check the voltages on them too and look at runoff grooves articles and compare your voltages to same type Q's in theirs.
  GEO tells about [general] tranny biasing in detail IIRC.Also the  Technology of the FF article is a must read [at least thrice IMO] for any new FF cloners.
  If it's still not Fuzzing 'right', and Q2 collector sits at ~4.5v, I would strongly suspect a miswire or resistor value bad.

[b_rogers]

would not having the correct value capacitor to ground (22) cause the problems im talking about?

[b_rogers]

is that 22 uf or 2.2?pf

[b_rogers]

i am an idiot..they ar uf

[b_rogers]

it is working! it sounds great...it was the wrong value to ground that was screwing it up...i am gonna go swap out trannies for a while..i have a bunch of ge from a old radio..thanks for your info guys

[ErikMiller]

One of my favorite pastimes, trying different trannies in the FF circuit.

Remember to come up for air once in a while.

Congratulations on getting it to work.

[b_rogers]

WOW  it is amazing to me that almost every transistor in the 15 pack sounds different..some pick up rf, some dont. some are gain monsters and some are milder..i have already came up with the best combo..q1=3904 q2=2n2222 cin=.o1 cout=.01  band of gypsy city..it sounds really good exept for a little spanish radio..any way to tune that out?  i havent put it in a box yet so maybe that will help..

[bwanasonic]

it sounds really good exept for a little spanish radio..any way to tune that out?  i havent put it in a box yet so maybe that will help..

From the Sili Face article at www.runoffgroove.com:

"To block RF and other noise, Gus Smalley suggests a 10k resistor in series with the input and incorporating a power supply bypass cap."

I would guess you will get less RF in an enclosure. I recently took my homemade Ge FF down to my local music store, and they were nice enough to let me A/B it against a certain boutique Ge Fuzz with four knobs. I was suprised to hear radio signals coming through with both mine and the *boutique*, as I have never had that problem at home or at gigs. I think the problem may have been the P90s on the Epiphone Casino I was using. Either that or they are located in a particularly evil spot for RF.  BTW- my FF held it's own tone wise, but I will never approach the build quality of this  boutique pedal, even in '69 years.  :wink:

Kerry M

[petemoore]

You can drive yourself nuts for hours trying transistors...you'lll find kool usable tones here and there too.
 Sometimes I's interesting to go for less than max gain by using the knobs on everything [including the guitar and using lower gainer's [especially Q1], you can get into nice overdrive tones or even booster type sounds. Those in[between settings can be real kool but you might have to play em a while to find out how to 'work them'.
 I have every confidence that you are figuring it out.
 watch the pinouts when you're swapping those Ge's and other Q's ,you could damage them by plugging them reversed.
 Box tends to help Rf, and there are fixes I haven't tried [small cpas to ground at input I think??? They're around, but I always got around having to use them, severe Rf fixes may alter tone of ckt. I hooked a test clip and a wire in the middle places of a Ge FF and got some great reception of wierd stuff, some of it sounded foreign...too funny, had to listen for a while.
 A mod an input is put two caps in parallel of bout less than half the size [I don't remem or know what values...exp. with say .0047uf through .047uf er whatever round there] and have a bass boost or treble boost or regular incap setting
 
                          ---     CAP Switched  ------
  In from jack <                                               > Q1 base    
                          ---      CAP connected[?]  ----
 Just trying different input caps is a good thing to try on a first FF using a socket [or test clips?].

[b_rogers]

i am thinking 6 position rotary switch with different caps for input, or doing the blend pot...that 6 way looks confusing to wire, and the package doesnt have a schem...i read a 47pf cap to groud off of main input will stop the rf...i will try it tomorrow..by the way i used 8 pin ic sockets for the tranny sockets worked like a charm...i always thought i could get close to the jimi woodstock tone with my ts-9 and marshall jackhammer after my sweet ultra..but this is it! my buddy is gonna FREAK when i bust out star spangled banner...FUZZ RULES

[Gary]

b_rogers

To get rid of the RF you might pick up, try sticking a small resistor between the input jack and c in.  Try about 10k.  You'll give up a tiny amount of fuzz, but the RF will not bother you anymore.

Good luck

Gary B

[petemoore]

I havent' shielded any in/out wires for sometime but my innards layout keeps these wires reasonably short.
 The box should help, it WILL repel electrons...but RF can be tricky to find where it's getting in.
 I just use the bypass switch or play to make the last tiny bit of rf [almost] totally unnoticable...
 The band likes to hate it though, dude calls out a song then takes forever talking about the teeny little announcer that got in there [a Boosted CB I believe] even though they get it through the PA also,... when it happens to a DIYer [like me] they see it as something to dwell on...if they'd just start darn the song after calling it, the rf would be totally unnoticable...lol...it's so faint ya gotta listen intently to catch it...
 Some ppl just like to pick...well when MY sound pales in comparison, I look for nitpicks about the other guys...they were totally anti DIY when I started...they're pretty much starting to figure out that I've got something really magic going on with the guitar tone thing now.
 I tried getting them in on it...but the response went like this: "Why can't you just buy a tried true commercial pedal like the rest of us"...dohh...
 ...." I didi that for years and now realize it pales in comparison to tweekin yer own..."