Share your opinions about AC125

[Ofek Deitch]

Hi,

I found a listing on the bay where 150x AC125 are sold for about 25 bucks, so I wanna know a bit more about these transistors before placing a bid.
What are these good for? I've seen some used in Fuzzarounds and Grease boxes. Are these good for Tone Benders and Supa Sustains?

I've never bought Ge. transistors before, so can you tell me what prices are normally? is this a good price?

Please answer quick, cuz listing ends tonight!
Thanks!!
Ofek  

[midwayfair]

As fat as 'what they're good for', look up the data sheet for the HFE range and otheir characteristics.

Chromosphere swears by them, but the batch I got were leaky and seemed picked over. Probably not from the same source.

Any batch of germanium transistors is going to have some waste, regardless of part number or provenance, when you're looking to plug them into existing designs. The solution is either tweaking the circuits to be less picky or design around them.

[Ofek Deitch]

It's a sealed pack so nobody went over it and took ones that are good

[Ofek Deitch]

This is what I found: I don't understand any of it but maybe you guys can tell me what this means for me

Type Designator: AC125
Material of transistor: Ge
Polarity: PNP
Maximum collector power dissipation (Pc), W: 0.5
Maximum collector-base voltage |Ucb|, V: 32
Maximum collector-emitter voltage |Uce|, V: 1
Maximum emitter-base voltage |Ueb|, V: 10
Maximum collector current |Ic max|, A: 0.1
Maximum junction temperature (Tj), °C: 90
Transition frequency (ft), MHz: 1
Collector capacitance (Cc), pF: 50
Forward current transfer ratio (hFE), min: 50
Noise Figure, dB: -
Package of AC125 transistor: TO1

[zombiwoof]

My understanding is that the AC125 is similar to the AC128, but with lower power handling specs.  I'm sure the ones you are talking about are the modern type in the smaller can (with the emitter tab and flange around the bottom, usually the Tungsram made ones like most of the modern AC128 types you find), the originals were the larger straight-sided can like the original AC128's with no flange around the bottom.  They supposedly sound about the same as the comparable modern small-can AC128 in a pedal.  I just bought a couple of tested matched pairs of them from Ebay, and have seen the full bags listed also.  I've also seen a few of the vintage larger can type on Ebay, but they are more expensive, as are the vintage AC128 type.  I haven't used mine yet, but I've read that they are a good choice for Fuzz Faces when tested within the suggested ranges.

Al

[ch1naski]

I've found that the data sheet will give you (speaking of germanium, now) an ideal set of specs, and then you hope and pray that the actual product you end up with matches as closely as possible. But usually, it doesn't go as smoothly as that, especially when buying in bulk off of eBay.

[smallbearelec]

I've found that the data sheet will give you...an ideal set of specs, and then you pray that the product matches. But usually, it doesn't go as smoothly as that, especially when buying in bulk off of eBay.

Yes to the above.

SBE has in recent times responded to competition by offering germanium devices for bulk purchase. I don't pretend to compete with the prices on E-Bay. However, I Do guarantee that the devices you get will be what I say they are. I have access to sources that these E-Bay sellers don't, and you'll find better, more consistent parts here, though necessarily more expensive.

http://www.smallbearelec.com/servlet/Categories?category=Germanium+Transistors%3ABulk+%22Rough-Sorted%22+Lots

Regards
SD