Germanium transistor gain testing dynamic vs static, small signal testing

[mozz]

Germanium transistor gain testing dynamic vs static. Anyone? I have a new old toy, B&K transistor tester/analyzer. Here's the story, say I test a silicon npn on my Dca55, reads gain of 80. I'm assuming this does a DC static test.  When I test on the b&k which does a AC dynamic test (60hz) signal, I get almost the exact same reading.

Switching to a germanium PNP, if it's 80 on the dca55, it may read 25 on the b&k, or it may read 50. Some are 60 and 120 on the dca but will both read 35 on the b&k. Leakages are not the cause or major cause anyway. I've put my finger on the tranny and got leakage as high as 1000ua on the DCA, gain drops slightly. On the b&k the reading will hardly move.

It just appears some germanium transistors are able to pass signal better than others even with exact gain and leakages from a DC static tester. The Japanese tranny's of course are much more consistent in reguards to both testing methods.

I do hopefully have another old transistor analyzer (hickok, triplett)on the way to verify my results. Some of these old analyzers do many tests and are basically lab grade.

I need to breadboard a fuzz and swap out and test a bunch of these. I've had cases were good testing tranny's sound like crap and other times poor testing sounds great.

[PRR]

Too much data makes Bob an unhappy boy.

Different test currents usually give different hFE.

In an ideal transistor, hFE would not vary at ALL with current. Then static and dynamic would be the same.

The older Ge parts had huge hFE variation, and could go either way for "normal" currents, which may be nowhere near the test-currents of your two testers.

Which B&K?

[mozz]

It's a B&K Dynamic Transistor Analyst 161. I think it uses 1ma when you set the beta cal to full scale. 60hz.

Silicon transistors read almost exactly the same on the DCA55 or b&k. From what i can now tell the DCA55 uses 2.5ma collector for tests. So, the silicon have about the same gain at 2.5ma static to 1ma dynamic.  A flatter curve? Or would it be a straighter curve?

Now the Germanium drop off gain wise 2.5ma to 1ma, but not at a 2.5-1 ratio. Closer to 5 or more.

I do have a line on a Hickok analyzer and a Triplett 3940 monster. If the price is right i may drive 2 hours to pick them up. They both use 1khz, Hickok is somewhat adjustable where the Triplett is very adjustable.