Hitachi 2SB77 project?

[philbinator1]

Hey guys,

i bought a little old trasistor amp (someones project) at the recycling centre today, and lo and behold it had four pnp germanium
transistors (2SB77) in it!  Score!  so my question is, what project could i build down the line that utilises these trannies?
Is is possible to build a fuzz with these that uses a -ve power supply?

cheers
phil

[anchovie]

Lots of threads come up if you put the part number into the forum search. There's a datasheet easily found through Google.

I'm sure they'd work in a lot of projects that call for a germanium PNP, whether they're the best choice or not will be revealed through the joy of experimentation!

[philbinator1]

Lots of threads come up if you put the part number into the forum search. There's a datasheet easily found through Google.

I'm sure they'd work in a lot of projects that call for a germanium PNP, whether they're the best choice or not will be revealed through the joy of experimentation!

i got the datasheet and it says that the average hFE is 85, however i'm getting values (after waiting for them to cool from handling)
around 160, one of them is even 244!  does this mean they're stuffed?  i did have a hard time desoldering them, they were really in
there...

[joegagan]

congrats! it is fun finding these old japan trannies in old devices at the thrift store. sony tape recorders used really nice germaniums back in the 60s. i think their standards were pretty good, and all the old hitachis i have tested were usually pretty good.

are you using the rg keen method to test gain?

i would build a rangemaster ( with variable input cap for more possibility) or easyface with those if it was up to me.

[philbinator1]

congrats! it is fun finding these old japan trannies in old devices at the thrift store. sony tape recorders used really nice germaniums back in the 60s. i think their standards were pretty good, and all the old hitachis i have tested were usually pretty good.

are you using the rg keen method to test gain?

i would build a rangemaster ( with variable input cap for more possibility) or easyface with those if it was up to me.

thanks, yeah it is fun!     i make pretty regular visits these days to the "dump shop" as i call it.  thanks for the advice...but what is the rg method?  i just used the trannie tester on my multimeter.

[Joe Hart]

Dude, you NEED to devour the Geofex site!!! That's where you'll find the "R.G. Keen method" of testing transistor gains.
-Joe Hart

[joegagan]

google search 'technology of the fuzz face' == rg keen's excellent article at geofex will come up.

rg wrote it in the paleozoic era of the internet, before al gore invented it. who knows how many hobby and pro pedal guys got their start at that exact page? tens of thousands i am sure.

thank you, rg.

measuring hfe of germs is inaccurate using a standard meter due to leakage. read the article, build the tester.

[philbinator1]

Dude, you NEED to devour the Geofex site!!! That's where you'll find the "R.G. Keen method" of testing transistor gains.
-Joe Hart

true, true.  i have been reading other stuff, but not that...yet   

[LPDude]

I just received the Tone Bender Pro MKII PNP -Generic Transistor set today from Small Bear Electronics and he gave me a 2SB77 to use in in Q1. The other 2 transistors are unmarked metal cans.