Perky's Guide To: Fuzz Face Transistors (Germanium NKT275 vs. Silicon BC108)

[@simonkormendy849]

I have a red Jim Dunlop JD-F2 Fuzz Face that I've been doing some work on, I replaced the original stock pcb in it that had two NTE158 germanium transistors on it because they died, I bought an issue 1 Fuzz Face pcb from Pigeon FX and used two CDIL BC108C NPN high gain small signal silicon transistors, the one in the Q1 position has a gain of 635, the one in the Q2 position has a gain of 660, these might sound like massive amounts of gain for use in a Fuzz Face, maybe too much, but I was very pleasantly surprised when I tried the pedal out after working on it, my red JD-F2 Fuzz Face sounds really fat thick and smooth, with lots of sustain and sizzle, it really sings if you sustain a note and add a slight vibrato, something like what Eric Johnson gets with his signature Fuzz Face but without that spittyness, the two CDIL BC108C transistors seem to bias-up fine with 1.1V on the collector of Q1 and about 3.7V on the collector of Q2 resulting in some asymmetry in the output signal.

[@Chrisdava]

Hi ! When the gain is at the max I prefer the Silicon. But in any other cases I prefer the Germanium. That's why I think it's good to have both on your pedalboard. Very good demo. Thank you !

[@JoePerkinsMusic]

Always good to have both! ;-) Thanks for watching mate :-)

[@komagome03]

Nice shoot out ! Thanks.

[@JoePerkinsMusic]

No probs mate - glad you enjoyed! :-)

[@kimhansen6384]

Brilliant review, as allways. I prefer the Ge, but am a little bit astound about the darker quality of the Si pedal. They use to have more high-end and attack than this. There has been written a lot about how to bias the Ge transistors, how to measure devices for leakage, and how much Q2 has to be different in amplification factor from Q1, but less so on the Si devices. Good Ge devices tend to have amplification factors from 60 - 150 and does not selfbias very well. BC108 Si devices tends to be from about 300 - 500, which probably accounts for the higher output. I am not sure right now how well they selfbias. But he bias affects the sound a lot.

[@TheYjmfan]

I built my own and used the bc108s sounds great .

[@thegolfnut812]

Germanium is the one I'd choose. Thanks for the comparison.

[@paulj0557tonehead]

NKT275 overall best. He could have put a screwdriver 50k input trim pot ( as per the Mike Fuller mod) on the back with a dip switch to put it in or out of the circuit. Here is what this simple mod does [ from *The Technology Of The Fuzz Face* site] : "Mike Fuller posted some recommendations on the Fuzz Face to the net. Among those are to add a 1K linear pot in series with the 470 ohm resistor in the collector circuit of the second transistor, still taking the output from the top end of the 8.2 K resistor. The pot is set up so it is acting as a variable resistor, wiper shorted to one end lug. Another is to connect a 50K pot, again as a series resistor, in series with the input of the circuit, before the 2.2uF input capacitor. Fuller Suggested Modified Fuzz Face If that last one seems a little odd, think back to what I said about the low input impedance. With a low input impedance, the input loads a guitar significantly; the base can only move a few tens of millivolts before cutting off or saturating the first transistor. If you put a resistor in series with the guitar pickup, it raises the apparent source impedance of the pickup, making it look more like a current source (albeit a tiny one) and less like a voltage source. A signal from a current source lets the input of the effect seek it's own voltage level, and merely supplies a varying current. This can be much more linear than a voltage source drive. As a result, the variable resistor allow you to radically clean up the distortion that the FF produces, producing subtle shades of softer distortion. In effect, the output mod is a "more" control, and the input mod is a "less" control. As you would expect, the two added controls can interact to produce many shades of distortion. One person reverse engineered the Fulltone "69" pedal and has posted the 69 pedal schematic to his web page. In this schematic, you can see Fuller's application of his earlier suggestions. The "69" pedal does enjoy a good tone reputation. If you like softer distortion, you might also like to add some high end taming capacitors. Adding 10 to 100pF from collector to base on the second transistor or 100-680pF across the collector resistor of the first transistor will soften things up a bit."

[@stevenburvenich168]

Great comparison. I remember a period in time where most people adored germanium and crucified silicon. I still try to imagine why. Perhaps many silicon fuzzes were misbiased, don't know. Fact is, high temperature makes germanium less comfortable. Fact is, germanium leaks much more than silicon, even the "good" ones. Fact is, many silicon fuzz design today are actually just as warm sounding if designed so. One of the crucial factor is biasing or "fine tuning" the settings of the circuit. If all bias is equal, no transistor will sound the same. That's is why early fuzzes different and were choosen by ear: some transistors were very good for the set bias. But if you tweak the bias, you can find much more good sounding fuzzes. Another thing is the gain of the transistor. No transistor is exactly equal in gain. Germanium is lower (NKT275 current gain of 70-100), silicon is higher (BC108 up to 450). But there are lower gain silicons as well, that can be used in a different bias and give a "tamed" silicon fuzz.

[@JoePerkinsMusic]

They're certainly all individual! I think on balance I prefer Ge transistors, but that's just personal preference - I've got some Si fuzzes and they sound absolutely amazing!

[@Magnulus76]

I had a fuzz pedal that I thought was germanium... it certainly had a vintage "fuzz face" sound. I opened it up one day to look, and the transistors are in fact inexpensive modern silicon ones. But the circuit is definitely a vintage fuzz face type. So I really think the circuit and the rest of the components are even more important now.

[@Mark70609]

I have a Fulltone 69 and 70’s Fuzz and the difference are very noticeable. The thing I notice is how they react to turning the guitar down. The Ge 69 pedal practically drops all of the Fuzz with a slight movement of the volume pot. The Si version has more gain and the Fuzz tapers off as opposed to dropping out.

[@zwoelf160]

Great Demo... thx

[@darwinsaye]

I think so much depends on individual pedals and signal chain and other factors. You demo doesn't jive with most videos I've seen comparing the newer germanium Fuzz Faces and Fuzz Face Minis to the silicon counterparts. Generally I've found the germanium to have a darker and thicker tone when full up than the silicon ones, and the germaniums clean up more completely than the silicons, but sometimes seem to clean up less bright than the silicons. So many things could be making these differences. I just bought the new EHX Ripped Speaker Fuzz, and found that against all common assertions that fuzz should never follow a buffered pedal, this one holds up well no matter where it's placed in the chain, and the guitar volume cleanup is actually vastly improved when placed after a buffer. In fact I've never heard any other fuzz clean up so completely and get more glassy than this one does, even though it's after a buffer. I know some of that may be related to the 50's Les Paul wiring mod I did in my Tele, and how that *may* be somehow affecting the way the buffer affects it, I don't know, but the cleanup and glassiness of that thing is bloody astonishing.

[@JoePerkinsMusic]

It's absolutely pedal specific, for sure - the 'type' of transistor is only a smallish factor in a whole system. A lot of modern Fuzz Face pedals are designed to not require an impedance mismatch on the input to filter the sound and for the cleanup to work - they work fine after buffers - and in those pedals, giving them a buffered signal actually helps to retain sparkle when rolling the guitar's volume down; just like it would with most other gain pedals. So there's a lot of things at play :-)

[@LostPlanet2024]

I landed on the BC108 FF. These need to run into to a mid focused amp that’s pushed into OD or and drive pedal to simulate a saturating amp..

[@flatfifth5876]

man i love my Germanium fuzz's. but they are a pain in the well butt! they don't play well with others and always want to go first in the chain. gotta love em! nice demo thanks.

[@JoePerkinsMusic]

Ah me too :-) They're definitely temperamental beasts though, you're right - fortunately the temperature doesn't change too much here!! Heh I've just ordered myself an NKT Analogman Sun Face, so I'll have to shoot a comparison between the Cornell, JAM Fuzz Phrase & that once it gets here...we can have a proper Ge Fuzz-Off!! Hehe Thanks for watching mate :-)

[@Magnulus76]

I've encountered the same thing with a silicon fuzz circuit. It really has more to do with the unbuffered input stage of most fuzz pedals, which has its positives and negatives and contributes to their unique character (with a buffer in front of them, they tend to be less responsive).

[@mikeroadblock]

Nice!!!

[@LewWelchThePoet]

👍🏿🤘

[@mrbaiser4133]

Compare zinc and alcaline again, with batteries that are down to maybe less than 7V. The difference will be bigger, because the resistance of the zinc battery will increase more.

[@Ian_sheridanuk]

I think the silicon is more sweet and musical

[@jameskavanagh4300]

Both clean up nicely, but when the guitar vol is rolled up I think they both sound ghastly

[@63FenderStratocaster]

They didn’t switch to BC108 directly from NKT275. They went to BC183L in 1968 which are very different from BC108. Implying that there were only two choices in Fuzz Faces is misinformation, even if it’s not intentional.

[@JoePerkinsMusic]

Wasn't trying to imply that those are the only two options at all (CV7003 FF's are some of my favourites!) All this video was trying to show is the very first Ge vs. the very first Si that Dallas Arbiter used. Just a quick comparison between G/S Fuzz Faces :-)

[@63FenderStratocaster]

Joe Perkins I’m not trying to troll you, I’m just trying to correct the information because people see this and repeat it to others as truth and so on- which leads to uninformed opinions and internet arguments ;). I understand your intent- you wanted to show difference between 2 different transistor types used in the original fuzz faces. and to be clear, Fuzz Faces are specifically those big round smiley pedals made from 1966-1975ish. You did a great job broadly showing the difference between a germanium and silicon fuzz. my point was you said (and keep saying) that BC108 was the first Si Fuzz Face. This isn’t true. The BC183L was the first Si Fuzz Face, issued in 1968. And the differences between them and the BC108 are massive. It’s not just semantics. The Fuzz Face used only the following transistors in their 9yr run- NKT275, BC183L, TFK BC130c (rare but it existed in 69/70 era), TFK BC108c and BC209c. Those are also in order of their issuance. The BC108 came along around 69. I have examples of them all- but more importantly, it’s good just to have all the facts correct when speaking to an audience. I’m simply trying to correct simple misinformation when i’m able to speak with complete conviction on something. again, nice video. really and your broad point is expressed well enough.

[@kimhansen6384]

@@63FenderStratocaster And you forgot that a lot of the first Ge Fuzz Faces had AC128 in them :-)

[@coldfishpie]

@@kimhansen6384 I know Cornell made some reissues with AC128S in them and I know the story that the AC128 appeared in the early fuzz faces but I have never seen any evidence or know anyone that actually seen a pair in a 66. Not sure if its a myth or true such is life! :)

[@3rdtonefromthesun]

@@coldfishpie Analogman agrees with this as well... I suspect that Kim does not realise that Dustin Francis is a highly regarded Fuzz Face builder.

[@salx777]

want to sell the silicone one :)?

[@pjbarford]

Ahhhhh lava lamps