Just finished Germanium Fuzz, oooohh yeah, really nice!

[Burstbucker]

I just finished up my latest fuzz, it's a Germanium FuzzFace with added tone knob for the input cap.  I also used a 100k Audio pot instead of the traditional 500k pot for the volume control.

I built this FuzzFace with a pair of N.O.S. NKT 275 Germanium transistors that I bought off of a guy on ebay.  I can honestly say that this is the best vintage-style fuzz that I've ever played, wow!

The extra expense for those NKT 275s was well worth it.  By setting the volume knob on my guitar about halfway, the sound is quite clean with just a tiny hint of dirt but as you slowly turn the volume knob up to maximum you get this enormous range of fuzz tones, all kinds of shades of fat cholesterol.  At maximum, it almost sounds like a BigMuff!

I'm just too happy with this one, I built another all-Germanium FuzzFace last year which I really like but this latest one is the real deal.

Jimi-approved tone.  I wish I could post some pics but I don't have any right yet.   I'll have to get a friend with a digital camera to come over sometime.

[Outlaws]

Very cool.

I just breadboarded a Silicon FuzzFace and am going to test it tomorrow when I get some hookup wire that fits in my breadboard.

Did you measure the hfe (I think thats what its called) of the transistors?  

I am going to build a Germanium one soon.

If you don't mind, what did the NOS trannys set you back compared to a matched pair from SmallBear?

[Burstbucker]

The gains on these are pretty low but they're also not very leaky.

The gain of Q1 is 65hfe and the gain of Q2 is 70hfe.  At first I thought that those gains would be too low but they're plenty hot for my tastes.

I paid $20.00 USD for this pair of transistors, I think Small Bear's are around $11.00-$12.00 per pair.  I couldn't be any happier with the tone.

[Ivana]

Congratulations!  
I have some questions:
1) You take a standart Dallas Arbiter scheme? (33к, 100к, 8.2k, 470, 1k 22m etc...) or different?
2) what are the voltages on B C E of transistors? (I mean if they 65 and 70 gains the collector voltage of Q2 may be NOT 4.5 volts or you tweak it?)
3) Do you measure the REAL gain without leakage? Which method? (GEO or SmallBear or another one)
Thanks.

[Burstbucker]

I used the standard 33k, 100k, 470ohm arrangement but I put an external 5k linear "Bias" pot in series with a board-mounted 10k trim, these two take the place of the 8.2k resistor on Q2's collector.  This 5k pot fine-tunes the bias on Q2's collector, it allows you to focus in on the sweet spot.

I'm getting between -4.5 and -5 volts on Q2's collector when the "Bias" pot is set in the middle and it sounds best there.

Each transistor had already been checked for gain but I always check them using the method explained at GEO's website.

[Ivana]

Thanks for answers.
Just one thing: (IMHO, I may be not right) GEOs method measures gain at 4mA base current but Small bear - at 10mA. I have measured a half of one hundred transistors witn both metodes and I find that GEOs gain is typically less about 20% from Small Bear (80-GEO, 100-SB). I think that the gain increases with the base current. So, your trannys may be about 80~100 of gains under 10mA base current!  

[Burstbucker]

That's interesting because I've always measured a lower gain than what Steve Daniels had marked on the storage bag.  I thought that maybe his readings were off.

Is there something on his (Small Bear's)website that shows how he goes about testing the transistors?  Like I said, I use the method described on GEO's site and thought that was probably as good as it gets, but what do I know?  I'm basically a novice with a great ear for tone!    8^)

[Ivana]

On the SB site a 5F (FAC for Fuzz Face Fanatics   ) is exist. The method "bare bones" discribed there   . First he measure leakage and the second - TWO currents in time (B and C) and divides the C current minus leakage on the B current. I replace his 1M resistor with a many variant switcher (680, 750, 910, 1M, 1.1M etc) so I can measure the gains under 4mA, 5mA,...... 16mA base currents. I have a data and graphics in Excell (~30 trannys) and I can see a tendention   (soorry for my bad english  :roll: ). Typical values is from 75 to 110 under B current 4-12mA (if I remember correctly  :lol: )

[KORGULL]

Hi, congratulations on the new pedal!

Is there something on his (Small Bear's)website that shows how he goes about testing the transistors?

Here's that link//www.smallbearelec.com/HowTos/FuzzFaceFAQ/FFFAQ.htm

[Peter Snowberg]

Ivana, That's facinating!

I would love to see your analysis!

[Ivana]

   
http://gtlab.net/forum/index.php?showtopic=598

The file at the end of the 1-st post. (Германиевые транзисторы тест.rar) I dont know how can I attach the file to your forum  :oops:  :roll:

[Karmasound]

Did the person you bought of off ebay say they had been tested? Or were already tested? Or did you just get lucky?

[Burstbucker]

They were sold as a matched pair.  The seller is a guy who sells a pile of different transistors on a regular basis on ebay.

[Karmasound]

They were sold as a matched pair.  The seller is a guy who sells a pile of different transistors on a regular basis on ebay.

who was it ? i'd like to try some.  


minifux?

[Burstbucker]

The guy goes by the handle "stompOrama" on ebay.

[Karmasound]

cool, i bought a set of ac 187 and bc 108 from him, i like them alot

[Ivana]

Excuse me (topics author and oyhers   ) for the offtop but what you can say about my measurements?  :?: