Which ge transistors (not) to get for a great sounding Fuzz face ?

Started by j_flanders, August 08, 2019, 06:43:03 PM

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Electric Warrior

Even if you manage to get some they may be different from the ones that Arbiter used.

I once scored 4 of them. They were actual Newmarket made ones, but later production.
The gain range was pretty much as expected i.e. pretty low. Mine measure between 40 and 72, but as the datasheet gives a range between 30 and 90, this came as no surprise.
The real problem was that they leak too little (between 10 and 50 mA), so they wouldn't bias right with stock values. It took a 100k on Q1C to fix this.

tubegeek

I just today finished my first Fuzz Face, I used Jack Orman's positive power supply scheme and a pair of GE 2n525 germaniums I happened to have a few of, gains tested using the RG Keen circuit at about 45 on each one.

I used all stock values except the Q1 collector which needed 68K, replacing 33K. With the stock 33K value, it was gate-y and yucky.

I think 68K may have overshot - my trimpot was set to 61K and it sounded better - rougher! - than this standard-value substitution. So I may parallel a couple of resistors and see what that does - or maybe the temperature in my workroom changed and that's why. Does anybody have a reference for a temperature compensation diode scheme? I'll google a bit.
"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

j_flanders

Quote from: duck_arse on August 09, 2019, 11:22:49 AM
Ivan, at diy-tubes.com, in russia. if you ask him nicely, tell him what you want, and he might select some trannies for you. he has some goood stuff.
I e-mailed him twice in august after his holiday, asking nicely as instructed. Never got a reply... I can only assume it arrived in his spam folder.
So, I was looking for ge's again today, right when someone bumps 'my' thread. :)

tubegeek

GE Ge. 2 Fuzz Faces. I had so much fun building the first one Manhattan-style, I built a 2nd one right away, that one got a 100K trimmer for the Q1 collector resistor.





"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

duck_arse

looks like you've killed those box caps. manhatten is a style I'm yet to try. I've seen Jaycar has bags of "lands", two sizes, but knowing them I'd need to spend days sanding the bloody things before I could use them.
You hold the small basket while I strain the gnat.

tubegeek

Quote from: duck_arse on November 07, 2019, 07:58:00 AM
looks like you've killed those box caps.
'Cause I melted a corner or 'cause they are lying dead coffin-style?
Quote
manhatten is a style I'm yet to try. I've seen Jaycar has bags of "lands", two sizes, but knowing them I'd need to spend days sanding the bloody things before I could use them.
Just use strips you offcut from a board, and you can cut the strips for islands - an xacto saw blade is very handy. I made the 2nd one right away because I wanted to tweak the layout a little and because it's kinda fun. Super glue gel is good as is FRESH thin super glue. Old stale thin super glue is a no go.
"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

Roland

There was a Craig Anderton "guitar player"magazine article from the early 80's about original fuzz faces and the transistors used. If I remember correctly NKT 275's were used and mostly AC128's ...as a matter of fact the  techs from Europe and the US that were used for info on the article stated  that most fuzz faces repaired used ac128's...with some saying ALL had ac128's. 

There was also a poster showing Hendrix gear and the fuzzface with the bottom cover removed and you could clearly see the nkt275's were used in his.


Electric Warrior

#27
Quote from: Roland on November 07, 2019, 09:56:09 AM
There was a Craig Anderton "guitar player"magazine article from the early 80's about original fuzz faces and the transistors used. If I remember correctly NKT 275's were used and mostly AC128's ...as a matter of fact the  techs from Europe and the US that were used for info on the article stated  that most fuzz faces repaired used ac128's...with some saying ALL had ac128's. 


I've collected some data over the last couple of years. In over 500 Fuzz Faces I haven't seen one with confirmed original AC128s. I was able to confirm a couple of rare silicon variants noone had ever written about, though.

Edit: I just remembered: I've got a copy of that article.  ;D
It doesn't say that AC128s were ever used. It merely suggests the AC128 as a european equivalent for NKT275s.

duck_arse

tubegeek > cause they laying down, tired.

Electric Warrior > I was given a photocopied single page of anderton-on-fuzzface, back in the 80's [still have it], and it has a connection error in the circuit diagram.
You hold the small basket while I strain the gnat.

tubegeek

Quote from: duck_arse on November 08, 2019, 08:05:15 AM
tubegeek > cause they laying down, tired.

<insert not dead yet, just resting, Monty Python parrot joke>

BTW if ever there was a circuit suitable for Manhattan style, it's this one.
•very few components/connections
•highish gain, so happy to be groundplaned
•retro as f*ck.
"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

tubegeek

I got some enclosures on the most recent Tayda discount code, and so one of the Manhattan-style Fuzz Faces got a home today.

I can't really recommend these pre-painted Tayda boxes that highly: the heat generated by a step drill is enough to make the surface get a weird texture. Too cheap/good to be true.

"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR