Crawls Backward (When Alarmed)

IconProjects, musings about guitar builds, guitar repairs, vintage tube amplifiers, old radios, travel, home renovation, and other stuff.

Germanium Transistor Testing Results

The saga continues on the transistor testing. I did wise up and set up an Excel spreadsheet for the test results. That at least saves me from doing the math.


I brought my laptop down to the bench so I can just put the results in straight away.  There's also an interweb connection down there so I can get online.  If I had a cot, I could just take up part-time residence!

Here's what I'm finding with this batch of AC128 transistors:  out of about 40 tested so far, only three or four have over 300 ma leakage.  That number is the cut line for rejects.  Of the ones that are under 300 ma, most have a gain of under 70.  So most are probably not usable in a fuzz.  There are a handful that will be good for the first stage, and there are only 1 or 2 that may be high enough for the second stage.  I didn't have high expectations, so this has been a good exercise.  And it looks like I will have plenty to use in the first stage of the Red Pepper(s).

The good news is that I also bought a bag of 10 transistors from Small Bear.  These all seem to be US-made 2N404A devices, and all of them so far (about 5 tested) pass on the leakage test and also have good gains.  I have at least one pair already that is useable,  and I have a couple that will work as Q2 in the fuzz paired with an AC128 in stage one.  I'm encouraged at this point.

 
 
 
 

Post a Comment 0 comments:

Post a Comment