Best transistors for fuzz

[jm22]

First post here at DIYStompboxes. I'd like to try my hand at building a fuzz pedal, perhaps a Tonebender MKI or II. I have two fuzz pedals at present, a Langtronics Fuzz (hand built in England with AC128) and a Solid Gold FX Formula 69 (Montreal builder, silicon transistors). I have a friend who says he might have some old transistors and other components, and he's asked me for a list so he can check his parts bin. In my reading about fuzz pedals, I've come across a few that seem to be well regarded, like OC75, AC128, and a few others, but I thought I'd ask the Stompbox community for some ideas as to what are the best old transistors for fuzz. Any input would be appreciated.

[Phend]

Being the non expert in this forum, like negative 2, my suggestion is to allow quickly changing transistors to experiment.  A small mini bread board from amazon might help, got mine today, 7 bucks for 5.

[jm22]

Thanks for the reply and good idea. One thing I've noticed in my search to find what are regarded as the best transistors is how many different OC series transistors are mentioned. A fuzz seems to be about the easiest pedal to put together, but I get the impression that the magic is in getting the right transistors.

[willienillie]

...the magic is in getting the right transistors.

It's more about the specs (gain and leakage) of the transistors, rather than specific type, though that can make some difference too.  The desired specs will depend on the circuit you're building.  Often a circuit can be adapted suit to the transistors, like changing a resistor value, or using a trimmer in place of a fixed resistor.

[patrick398]

It's worth exploring the world of Russian 'equivalent' transistors as they can often be found more easily, are cheaper, and can be tighter spec, than the well known germaniums.

https://www.diystompboxes.com/smfforum/index.php?topic=117061.0

Beware of bulk buying germaniums on ebay, often these are the undesirables after someone has been through a big batch and cherry picked the good ones...

[cab42]

It's more about the specs (gain and leakage) of the transistors, rather than specific type, though that can make some difference too.  The desired specs will depend on the circuit you're building.  Often a circuit can be adapted suit to the transistors, like changing a resistor value, or using a trimmer in place of a fixed resistor.

Read "the technology of The Fuzz Face by R.G. and you will get much wiser on Fuzz faces (I have read it around 10 times, but I am getting there )

http://www.geofex.com/article_folders/fuzzface/fffram.htm

From the article:

I've also done some experimentation with germanium devices other than the AC128 and NKT275. I found a number of germanium types, measured their gains, and then listened to them. The results are pretty consistent - get the right gain and frequency response and the numbers printed on the cases don't matter.

Pretty much what Willie posts above.

I have PinkJimiPhotons Schizoid Face on the breadboard (Si Fuzz Face) at the moment and it sounds good almost no matter what trannies I use (allthough I like some better than others) as long as the gain is consistent.

https://www.diystompboxes.com/smfforum/index.php?topic=117221.0


I have some CV7112 NPN germaniums that I would like to try in a FF. They are in the lower end of the usable range, but worth a try.

[j_flanders]

If I want to hunt for my own devices, what type numbers do I look for?

This list of "candidates" may help. It is a compilation of things I have seen on other bulletin boards (Aron Nelson/Jack Orman/R. G. Keen), and my own experience with Japanese and American parts.

American JEDEC numbers

PNP: 2N321, 2N404, 2N404A, 2N508, 2N527, 2N1305, 2N1307

NPN: 2N388, 2N1306, 2N1308, 2N1309, 2N1373

American "Replacement" Types

NTE (or ECG) 101, 102, 158

Japanese

PNP: 2SA or 2SB 22, 54, 75, 77, 172, 175, 178, 187, 201, 303, 324, 370, 405, 439, 516

Of these, the types that have given me the highest yield of "good" devices are the 2SB175 and 178.

European

PNP: OC44, OC71, OC75, OC77, OC81, AC122, AC128, AC151, NKT275

NPN: AC127, OC140

http://diy.smallbearelec.com/HowTos/FuzzFaceFAQ/FFFAQ.htm

[jm22]

Thanks for all the interesting replies. I will study them.

[Mark Hammer]

I made one with a 2SC281 (germanium) and a BC108 (silicon) the other day.  Sounds great!

[iainpunk]

i really like my fuzz faces with silicon power transistors and trim pots, i build one a few months ago with a Q1 2N3055 and a Q2 BD139, which sounded awesome. i selected them out of curiosity, the hfe's measured at 33 for the 2N3055 and 88 for the BD139 (yes i chose them because i liked the double digits). and after some trial and error in the trimpots, it was a nice raunchy overdrive (because of the low gain.)

i have also build one (slightly modded) with 2n2222 with hfe's of around 110 - 120 (can't remember for sure) which sounded killer for sludgy doom stuff, when biassed right or just off

the one i sold had two ZD41 transistors, which sounded unbelievably fantastic after enough tweaking with the trim pots.

what i'm trying to say is that every transistor set with Hfe of less than 150 and more than 60 can be made to sound good, just use trimmers to dial in the tone by ear, not by numbers. and if you like overdrive instead of fuzz or you just like stacking dirt, you can go with lower gains

[mozz]

You can get fuzz with germaniums lower than 60 and higher than 150 no problem.

[mac]

What do you want to build?
A Germ Fuzz Face? You need non-leaky transistors.
A Germ Maestro Fz-1 or TB I? You need leaky transistors.
Are all germs the same? No.
It's not all about gain and leakage, the internal capacitance matters too.
For example, Toshiba 2SA49/52 or some Matsushita 2SA102 have the right gain and leakage for a FF. These are drivers transistors.
Toshiba 2SB56, Matsushita 2SB176 or Hitachi 2SB77 too. These are power devices for small old radios.
49/52 and 102 have less internal capacitance than the others so they filter less highs.
What group sounds better? Salt and pepper to taste!

Power transistors, Si or Ge, have higher internal capacitance and hfe fall faster with decreasing current.

Check Gus circuits with power Si.

mac

[mozz]

Thought I read once that 2SA were made for RF, 2SB were more towards audio. 2SA will have less capacitance hence will work at higher freqs. I have a lab grade LCR meter and I can check C-B capacitance, it is usually spot on if I can find the good data sheets on that device. Japanese tranny's are often fairly low anyway and really consistent. A lot of 2SA will work fine in pedals, yet I do remember 2sa70, out of a radio, even though the gain and leakage were in the ( so called) ball park, wouldn't work right.  There were American tranny's too, 2N1613 that measured great yet won't work at close to optimum collector resistors.

These numbers were off the top of my head, could be similar. I have some 2N274, close number to 2N270. Yet they are RF trannys, probably better sorted, with less leakage, they work fine in a fuzz, I just add 47 or 68pf across c-b to simulate a poorer audio transistor.

[duck_arse]

First post here at DIYStompboxes.

come on, fellas, no welcome?

I have a friend who says he might have some old transistors and other components, and he's asked me for a list so he can check his parts bin.  Any input would be appreciated.

collar the lot, whatever he doesn't want/can spare/is chucking. then get building. there are a lot of fuzzes to get through, but mainly the fuzzrite.


and, welcome to the forum.

[jm22]

Hmmm... Fuzzrite. Another vintage fuzz I hadn't heard of. I'll have to keep that one in mind to perhaps try, if there's a schematic around. Admittedly, I've never been a pedal guy but I've come to appreciate two, fuzzes and Klon clones. Seeing how expensive original fuzzes are spurred me to try to make some. I sent a list of transistors to my friend (who lives quite far from me) and he's going to check his parts bin. Will report back if he finds anything interesting.

For those who have played more than one of the same vintage fuzz, do they vary greatly in sound from unit to unit? For example, if you took two early Tonebender MkII's, will they sound very similar, or will they vary?

[antonis]

if you took two early Tonebender MkII's, will they sound very similar, or will they vary?

Even if all but one pedal items were of the absolute same value, remainder item's tolerance should be enough for wide variation..

P.S.
Welcome also..
(sorry Stephen..)

[Electric Warrior]

For those who have played more than one of the same vintage fuzz, do they vary greatly in sound from unit to unit? For example, if you took two early Tonebender MkII's, will they sound very similar, or will they vary?

My MKIIs are not early, but they are very similar in character. The MKIII/IV I played were rather similar to each other as well.

if you took two early Tonebender MkII's, will they sound very similar, or will they vary?

Even if all but one pedal items were of the absolute same value, remainder item's tolerance should be enough for wide variation..

P.S.
Welcome also..
(sorry Stephen..)

They used mostly 5% carbon film resistors in these. I guess that may help keeping them rather consistent even after 50 years.
But of course bias is a moving target with germanium transistors and the attack pot's tolerance alone can cause a wide variance in Q3 collector voltages (and thus tones)..

[antonis]

They used mostly 5% carbon film resistors in these. I guess that may help keeping them rather consistent even after 50 years.

Never got into trouble of read/measure MKII (or other similar effect) resistors tolerance but simply judging their E12 series values I'd result in 10% tolerance..

[Electric Warrior]

gold is 5% tolerance Only the two 10ks on the left have silver (10%) tolerance bands.

[zbt]

Q1 Panasonic 2SC829 Rank A, B
Q1 Fairchild S9016 Rank F, G
Q2 Panasonic 2SC828

Works for me

for silicon try add trimmer 200K between base and collector Q1 to get 4.5V