AC176 vs. Ac176K

[mordechai]

Question, and most certainly a dumb one:

I've heard a clip online of a Si/Ge Fuzz with an AC176K in the Q2 position, and it sounded GREAT.  I saw some AC176s available for sale on ebay, but I don't know if they are the same thing as the AC176Ks.  If there's a difference, what would it be?  If there isn't, please also say so, since I'd definitely like to give them a shot.

[smallbearelec]

Hi--

You have absolutely no way to know whether a given device will make your fur curl until you test for gain and leakage, plug it in on the breadboard, and try it. This is life in the DIY FF world. If possible, get from the seller the same guarantee that I offer, i.e. the right to return the devices for refund, less shipping, as long as not soldered and with full leads.

SD

[zombiwoof]

I believe the "K" designation means the transistor has the built-in heat sink.  I have an AC128K in my FF, the body is a heat sink that is rectangular-shaped with a hole in it.

Al

[mordechai]

Zombiwoof, does this mean that apart from the unit's sensitivity to heat/soldering/etc., it is otherwise the same?

[tubelectron]

Zombiwoof, does this mean that apart from the unit's sensitivity to heat/soldering/etc., it is otherwise the same?

I anticipate the answer of Zombiwoof : yes, it's the same. K = Kühler (in German. Remember AC/OC Q's are European) = Heat sink.

Don't forget that it is Ge transistors, and these are more ore less consistent in performances, from one sample to another one, to point smallbearelec's advice.

A+!

[waltk]

+1 on the Small Bear recommendation.  You're really better off buying from them...

http://www.smallbearelec.com/Categories.bok?category=Germanium+Transistors

[Jaicen_solo]

+1 on the Smallbear.
Vintage NPN Germs are extremely hit and miss, the technology just wasn't that great back then. PNP was much easier to make, hence much better quality and availability.

[Davy Boy Smith]

I just bought a few hundred unmarked PNP Ge transistors from the MIT flea market last a few weekends back for three bucks, I have a B+K Precision transistor tester and I must say it is about 3$ worth of junk, all have little or no leakage and the Beta hfe of the transistors is so high that in the standard FF circuit both transistors are in saturation. These were IBM engineering samples from the mid-70s each transistor has a serial number band on it and has IBM stamped on the top of the can. I also got three 2n107s and three 2n270s from another vendor in exchange for 10 transistors from the above lot and built a Maestro FZ-1 clone from those and frankly the FF sounded like a better final resting place for the two of the 2n107s. I love the MIT flea market, especially the last one of the year everybody is dumping.