Leakage?

[polifemo]

I´m learning about building Fuzzes and yesterday I found some germanium transistors in a local shop.
Today I went there with my "component analyzer" in order to pick some good ones. Problem is that I really don´t know what to look for...

Today I selected the ones with "the highest gain/the lowest leakage" but I suppose that sometimes leakage can be a good thing, or?

Regarding HFE I suppose that anything below about 40 isn´t of much interest (?) but what about leakage?
What is the highest leakage that can be acceptable/usable? (I suppose that this relates to HFE)

My plan is to build my way thru as many of the classic fuzz circuits that I can during this year.

I understand that it´s impossible to give an exact answer, but if you could give me some general guidelines I´d be happy  

Ps The trannies I picked today are a couple of black OC75´s, some OC72 and one AC128 (square) Ds

[R.G.]

I´m learning about building Fuzzes and yesterday I found some germanium transistors in a local shop.
Today I went there with my "component analyzer" in order to pick some good ones. Problem is that I really don´t know what to look for...

Have you read the geofex article on testing germaniums? That has some info buried in it, although it's buried fairly deeply.

Today I selected the ones with "the highest gain/the lowest leakage" but I suppose that sometimes leakage can be a good thing, or?

That's a good general practice. If there was an "ideal germanium" it would have a gain of 80 or more, and the lowest leakage you can get. You're unlikely to get leakages below about 10uA. Less than that and I'd start being suspicious of the testing apparatus. It could happen, but I'd be suspicious. Over 300uA gets really difficult to deal with in a circuit.

Leakage per se is never a good thing. However, there do exist circuits which take advantage of unavoidable leakage for biasing. This is rather like making lemonade when life gives you lemons; unfortunately, what you wanted was beer, not lemonade. 

Regarding HFE I suppose that anything below about 40 isn´t of much interest (?) but what about leakage?
What is the highest leakage that can be acceptable/usable? (I suppose that this relates to HFE)

My plan is to build my way thru as many of the classic fuzz circuits that I can during this year.

Shoot for hfe ~ 75-150 and leakage under 300uA. Then be prepared to swap them around and notice what happens as you swap so you can select the best sounding ones in the circuit.

[polifemo]

Thanks.