Posted by
alex.s on
URL: http://guitar-fx-layouts.238.s1.nabble.com/Great-Jumpin-Germaniums-Ge-Diode-and-Transistor-Reviews-Discussion-tp13256p15237.html
Finally got round to testing my small stash, mostly of GT308V (plus a few goodies from everyone's favourite eBay seller..!).
I used the RG Keen germanium tester method, using a four pin socket in a BCBE configuration to accommodate both BCE and CBE pinouts without twisting and/or heatshrinking
First of all I can confirm what I alread read, those transistors are remarkably consistent and with remarkably low leakage.
My 20 GT308Vs all ranged between 0.012 and 0.036 in leakage, which is great, but somewhat disappointingly the consistency extended to their gains, meaning I will need reinforcement to actually get some matching done.
The gains ranged between 46 and 69, with only five of them in the 60 or more territory.
Goodies wise, I had:
two Texas Instrument 2N1307s one hfe:81 leakage:0.057, the other hfe:175 leakage:0.182
three GT2 308 (gains: 108, 113, 159 with leakages between 0.065 and 0.146)
six SFT308 which were quite hit and miss (gains between 40 and 140, leakages between 0.094 and 0.995, plus one wildly off the scale..!)
All in all it's a good starting stash, but will need to source some higher gain PNPs to pair up as I'm stuck with mostly low gain trannies.
Just thought I'd share these finding as some people might be interested in either comparing their result with the same kinds of transistors or looking to place an order.
Sonic findings to be posted at a later date..! :)
Ending with a question for everyone... I noticed a pretty solid trend in terms of gain/leakage ratio, in that the vastest majority of my higher gain trannies also had slightly higher leakage compared to their lower gain counterparts... Any explanation for this? Is this a common thing?
Thanks, and hope someone might benefit from this (small) contribution to the cause of weird and wonderful soviet Germaniums..! :)