silicon transistors vs germanium for fuzzface clone

[formerMember1]

i got a pair of germanium transistors off small bear. q1 90 and q2 129.
i blew up the 90 hfe so put in a nte... w/ hfe of 80.  I was wondering two things...

WHERE CAN I GET A MATCHED PAIR OF SILICON PNP TRANSISTORS?

IS THERE ANYWHERE TO GET EUROPEAN NKT275 OR AC128'S?

I THINK THE EURO'S SOUND BETTER THAN THE AMERICAN'S.


PS:i liked the small bear american ge transistors but would like the european transistors of ge and si.

:?:

[petemoore]

Here are some to try, FFs' transistors should be looked at subjectively, anything with the 'right' #'s [gain and leakage] should work well, they all sound at least a little or Alot different, find the ones you like.
 2n2369...great for the Q1 [low gain] positiion in Si FF's
 2n4401 ... if you find one that's low enough gain [Q1]
 2n2222 [if low gain for Q1]
 Any combination that biases, 'works'.
 Of course the transistors must be PNP for Pos Gnd or NPN for Neg Gnd FF.
 High gainer in Q1 may not improve the guitar volume/gain rolloff.
 Anything can go in Q2 position, over 150hfe gain isn't 'necessary'.
 There are lots of FF derivitaves, ones that use high gain transistors in both positions...and at least a 'few' others.

[formerMember1]

thanks. ill try them.

WHERE CAN I GET THEM?

SURPLUS STORE OR RADIO SHACK?

SHOULD I TEST THEM BEFORE I BUY THEM FOR GAINS IF POSSIBLE?
THANKS AGAIN

[mojotron]

Hi formerMember1, The place most people get transistors is either http://www.mouser.com/, http://www.digikey.com, or smallbear. There's no need to test them before you buy them, perhaps the truth is that there is no way to test them.... but, I have never gotten a bad Si transistor from either of these sources. Ge transistors is a different story... I use an NTE102A an NTE102 combo and get a sound that is indistinguishable from that of 2 NKT275 parts.

I think most people that have spent a lot of time building fuzz faces and comparing transistors would say serveran things that they have found:
- Ge parts sound very different from one another and Si parts generally are less differentiated - except by hfe.
- The hfe ballance of ~80 for Q1 and ~120 for Q2 is what is really important to get the classic FF sound
- Ge parts do sound slightly differnent, but with some circuit work an Si FF can sound very close to the same, but with Si parts you get more flexibility
- The hype of NKT275 and AC128 tansistors is earned - they do sound great. But, with attention to details and by researching the archives of this forum, you can make a FF circuit that is far better... So, there's no reason to seek out mojo parts...

[smallbearelec]

formerMember1--

A few comments and suggestions:

--As other people have noted, you don't have to use PNP devices. The 2N4401 and 2N2222A will work, and I carry those. I will put the 2N2369 on my "want to buy" list.

--I offer U.S.-made "work-alikes" of some popular silicon NPN European devices like the BC108 and BC109, and some like these for fuzzes. Check my list when I open tomorrow.

--Many European germanium types are advertised on E-Bay. Do go shopping there, but carefully! The seller should guarantee to take back (unsoldered) any devices that turn out to be leaky or hissy. You should have a solderless breadboard so that you can test your purchases quickly. Be aware that fakes of the NKT275 are common, and I have heard unhappy stories about the quality of the modern re-makes of the AC128.

--For AC128 from a trusted source, try Banzai Effects and give my regards to Olaf Nobis.

--I will have in a few weeks some NOS Mullard OC71 and OC77 that I expect will be worth trying.

Regards
Steve Daniels

[formerMember1]

thanks i'll banzai effects and give regards.

my fuzz is ge pnp. so don't i have to stick with si pnp? i was going to buy sockets off you(small bear) when you reopen so i could interchange transistors till i like them. (i have bias pots hooked up.)  
thanks

ps:do you sell silicon transistors pair matched.  (pnp)
also a quality(switchcraft...) stereo jack for treble booster clone??
"       "   "         stomp switch? i like fulltones quality 3pdt but i can't get them off him and my dealer in my area can't get em either.

thanks again ill shop at your site when your back open.

[formerMember1]

double

[formerMember1]

sorry everybody i dont know why it posted twice of same post. whoops...

[phillip]

Chances are you won't find anyone selling matched sets Silicon transistors since they're cheap enough so that you can buy 10 or 20 from Mouser and have more than enough good combinations.  Generally, with Silicon transistors in the Fuzz Face, you put the lower gain one in Q1 and the higher gain one in Q2 and you're off and running.

There are a LOT of fake (new production) AC128 and NKT275 transistors on eBay being sold for far more than they're worth.  They're easy to spot because they look like tall "top hats"...tall and narrow with a flange around the bottom.  Original AC128s and NKT275s weren't as tall and were fatter with no flange around the bottom.  I've had a couple of the new production ones and they sound pretty horrible.  Check out the link below...it shows the different types of AC128 transistors, including the real one (at the top) and then the fake ("The Modern").

http://www.geocities.com/stompbox2001/ac128.htm

For what it's worth, I would scour eBay for the American-made 2N-series Germanium transistors, both PNP and NPN, since they're not prone to being fakes and they're usually a lot better than other types that you'll find elsewhere.

Another option is to bypass the whole Germanium thing all together and build an Axis Face Silicon Rev. 3, which is a Silicon-based Fuzz Face circuit that nearly perfectly replicates the general tone of a Germanium circuit.  The best part is that you don't have to buy expensive matched Germanium transistors...you only have to get a few 10 cent each Silicons.  My personal favorite combination in the Axis Face Silicon is a 2N4400 in Q1 (gain around 74) and a 2N2222 in Q2 (gain around 125).  I set the voltage on Q2's collector for 5.0V.  I then lower the value of the 0.047uF capacitor that parallels the 1K2 resistor to 0.033uF to pass more treble.

http://fuzzcentral.tripod.com/axisfacesi.html

Hope this helps some!
Phillip

[formerMember1]

hey phillip thanks alot!!

that really helped me. i didn't know one could get close to a germanium fuzzface with silicon & also that they were cheap.  I also know that silicon will be more reliable temp wise since my germanium fuzz changes dramatically with temp variation.(took me a while to figure it out)

that axis face silicon fuzz... is that based off of roger mayer's axis face or what.

thanks again man you stopped me from spending a bunch of frustrated hours!!!
i'll post up in a week or so and let ya know i made out.

[petemoore]

Si Axis Face.
 Simple, reliable, inexpensive, great sounding...worth building a board for.
 General FF tips, I've read/used.
 HAS to be wired right [may sound obvious but it's true...lol]
 Know your transistor gains [or what you're doing]
 Socketting caps and transistors and trimpotting Q2CR lets you Tune the darn thing...might as well do one up like this since you Will either be using Your guitar and amp or something else...theory is that a FF should be flexible or tunable to the end user.
 Pregain works like your guitar knob, but sets the 'cieling', a nice addition because if you're like me, the CW [full on] stop on your guitar volume is a very easy 'preset' to hit. being able to hit 'that' sound without tuning the guitar volume knob may be of some use to you. You could do it with a fixed resistor. This makes it easier to hit the less wooly point at 'full on' saturated fuzz.

[formerMember1]

thanks petemoore

man you guys on this formum are really helpful!!

I am in the midst of waiting a few days for a shipment to come from mouser.(for a dallasrangemaster i am building). so the axis fuzz will be my next project definitley. i am going to research and get right parts.

PETEMOORE OR PHILLIP:
DOES IT MATTER WHAT COMPOSISTION THE CAPS ARE? IN A GERMANIUM FUZZ I WAS FOOLING WITH IT SEEMED THE FILM CAPS WERE SMOOTHER AND THICKER THAN THE "GRAINY" TINNY SOUNDING CERAMIC CAPS.  yeah i know it may be mojo, but i expeirenced this first hand.  


hey phillip thanks for posting that link for the axis fuzz. i was never at that site and it looks good for info.

[petemoore]

Those brown flat caps...I don't use 'em...sept in 'emergencies' or if it doesn't matter...I don't have any in my signal path. I'IM 'sure' I heard a difference between input cap types on a FF once...could have been a bad cap or even tolerance/value difference. But I AM Sure I heard a difference between a full circuit made with 'good' caps to one with brownies sprinkled in.
 For a mouser part # of AVX Box Metal Films [thanks Phillip for the info] check out Fuzzcentral Liquid Drive...these a nice caps I like to purchase.
 Other than that greenie chicklet caps are so good as to be almost indiscernable [someone disagree...] from more expensive ones.
 Electros are electros...you can put a teeny non polarized cap in parallel to pass the high frequencies better, I read [I tired/couldn't tell any diff myself]...I wouldn't bother again, not in a FF anyway.

[phillip]

The Axis Face isn't at all like the Roger Mayer Axis Fuzz.  The Axis Face is a compilation of a lot of great mods to the Fuzz Face circuit by a lot of great people.  The "Axis Face" name comes from my commercial effects pedal company, Axis Guitar Effects.  The Mayer Axis Fuzz uses a different circuit all together and has a very fuzzy sound.

I would use polyester film caps for most of the capacitors...unless they're too large of a value like 2.2uF or 22uF (in the stock Fuzz Face circuit).  Mouser does sell a 2.2uF AVX boxed metal film capacitor, but I bet it's a BIG one...even though the AVX boxed caps are very small and space efficient (not to mention super high quality!).  In the Axis Face Silicon circuit you'll only have to use radial electrolytics for the 100uF power supply filtering capacitor and the 15uF capacitor attached to the wiper of the "attack" pot.  Check out the Axis Face Parts List link at the bottom of the page for a full list of Mouser part numbers.  It also directs you to Aron Nelson for the "blue" 3PDT stomp switch.  The only down side is that I think that Mouser is temporarily out of stock of the 100K audio taper 16mm pots...at least they were when I ordered from them Tuesday of last week.

For the 100pF capacitor in the Axis Face, I found that only a Silver Mica would give the desired tone...a ceramic gave the circuit a wierd "crackly" sound in the decay.  As soon as I put a Silver Mica in there, the crackly sound disappeared and I've been happy ever since

Phillip

[formerMember1]

is there any sound sample's i could here on line.

you said the roger mayer fuzz is very fuzzy sounding.
is the axis face silicon more like a tubescreamer than a fuzz?

i am looking for a fuzz not smooth overdrive to smooth distortion...

thanks

[phillip]

The Axis Face is definitely a fuzz...it's just a very warm and smooth sounding Silicon Fuzz Face that's designed to closely replicate that sound of the Germanium Fuzz Face circuits, except it usescheap and temperature stable Silicon transistors.

The "Smooth" control is very useful in the circuit for mellowing out the texture of the fuzz.

Phillip

[formerMember1]

oh... ok cool
thanks again for the help.

IS IT POSSIBLE TO BUILD THE AXIS FACE ON PERFBOARD OR SOMETHING?
SINCE I AM GETTING INTO EFFECTS BUILDING BUT NOT PERFECTED IT YET.
I HAVE READ ALL THE INFO ONLINE(GEO,ETC...) CONTAING WAYS TO MAKE BOARD AND SUCH.

I HAVE A DUNLOP FUZZFACE JDF-2. SOUNDS HORRIBLE OBVIOUSLY.
BUT I HAVE BEEN MODIFYING IT WITH SOMEWHAT RESULTS BUT NOTHING I AM PROUD OF.  IT SOUND BETTER THAN IT DID WHEN IT WAS STOCK BUT NOTHING GREAT. IT IS GERMANIUM.WITH SWITCH ON BOARD.  IT HAS WIRES COMING FROM JACKS AND POTS TO A PLASTIC PIECE WHICH SNAPS ONTO THE PRONGS SOLDERED INTO BOARD.

MY QUESTION IS: CAN I JUST CLIP OFF PLASTIC CLIP THAT WIRES CONNECT TO THAN USE ROUND CASE,JACKS, AND POT (I WOULD CHANGE ONE TO 100k)
AND BUILD THE AXIS FACE ON A NEW BOARD OR SOMETHING AND WIRE IT UP TO EXISTING PARTS IN PEDAL.
I WOULD BUY A NEW SWITCH THOUGH SINCE IT IS SOLDERED TO PC BOARD AND IT SUCKS ANYWAY. I WOULD JUST THROW OUT ORIGINAL BOARD. ALSO EVERYTHING IS WIRED UP ALREADY.

THANKS AGAIN MAN...
:?:

[petemoore]

I'd recommend perfboard, follow the schematic diagram ~ when designing the layout, a fairly small piece of perf should do, the perf can be cut, steady hand or I recommend the straight edge, score along a line [or both sides] then break off a 'straight' [of 10 or 12 holes tall], you can cut for length after you get it populated.
 If I had a 'bad' FF, I'd work with that board...put a trimpot on Q2CR would be the first thing I'd do, then try to set bias...actually I'd check bias first.
 A temporary trimpot can be used...use the trimpot to find the resistance that sets proper bias on Q2 [20k or 10k with a 4k7 off one end, it works for me], after setting bias, remove the Q2 test resistance [pot or pot with resistor 'upping' it's range] without readjusting it, then measure and replace with about the same value fixed resistor [I'd use this method on a FF that has no room for a trimpot or I knew I'd want the transistors biased differently only once or twice...for a flexi FF [or any other I build] I use the trimpot mounted on the circuit board.
 ...a 10k pot ranges from 0k to nearly 10k,
 a 10k pot with a 4k7 resistor ranges from 4k7 to 14.7k [10k + 4.7k].
 Not sure what you're saying, you can install a new board in the FF case, and use or not use the offboard components.
 If I were new, I'd do some boxing, as it presents the bypass switching problems...leaving your FF working 'till you get a spare figured out...then, if the 'spare' sounds so good you 'have to', put it in the circle case. I don't know what your stock FF is worth or if modifying it raises or lowers it's $ value.

[formerMember1]

I ALREADY ADDED TRIM POTS.
I BIASED IT BY EAR. IT SOUNDS GOOD BUT NOTHING EXTRAORDINARY.
I DON'T CARE ABOUT THE VALUE OF FUZZ. I BOUGHT IT FOR 95 BUCKS TWO YEARS AGO AND NEVER LIKED IT. SO I STUCK IT IN THE CLOSET. THEN ABOUT 3 MONTHS AGO I STARTED FINDING OUT ABOUT MODDING IT AND BUILDING PEDALS ON THE INTERNET. AS YOU'VE GUESSED I AM ADDICTED. I PUT IN GE TRANSISTORS. NTExxx... Q1 IS 80 AND Q2 IS 129 FROM SMALL BEAR. I CHANGED THE OUTPUT CAP FROM CERAMIC(STOCK) TO POLY FILM. SOUNDS ALOT BETTER THAN STOCK FUZZFACE.
MY PROBLEM IS IT SOUNDS GOOD FOR A WHILE, THEN LATER ON THAT DAY I MIGHT PLUG IN AND SOMETHING JUST WON'T BE RIGHT. IT WILL SOUND LOUSY.  I THOUGHT IT WAS TEMP CHANGES BUT BEGINNING TO DOUBT SINCE I READ SOMEWHERE THAT WHEN IT HEATS UP IT LOSES GAIN. MINE SEEMS TO GET MUDDY AND UNFOCUSED WITH MORE GAIN.

YOU SAID

Not sure what you're saying, you can install a new board in the FF case, and use or not use the offboard components.

I MEANT CAN I JUST DISCONNECT THE CURRENT PC BOARD I WAS MODIFYING AND BUILD THE AXIS FACE ON PERFBOARD AND USE THE WIRES THAT USED TO GO TO THE OLD BOARD AND WIRE  UP THE AXIS FACE(PERFBOARD)TO THE JACKS AND POTS THAT ARE ALLREADY MOUNTED IN THE PEDAL.

IF YOU GO TO http://www.analogman.com/fuzzface.htm   AND SCROLL DOWN TO BOTTOM OF PAGE YOU WILL SEE WHERE HE TAKES OUT ORIGINAL BOARD AND INSTALLS HIS OWN.  BUT WHAT I WAS WONDERING WILL THE PEDAL NEED TO BE REWIRED SINCE I AM REMOVING A GE FUZZBOARD AND PUTING IN SI FUZZBOARD.
THANKS AGAIN and i apologize that i can't explain it more clearly

[amz-fx]

IS THERE ANYWHERE TO GET EUROPEAN NKT275 OR AC128'S?

I've got plenty of AC128 and AC188 transistors left... http://www.muzique.com/pcb.htm#trans

Read more about how they stack up in FF circuits on Jacques' site at http://www.geocities.com/stompbox2001/ac128.htm

regards, Jack