Ge transistor leakage,question about Russian GT404b

[kupervaser]

You shouldn't pay too much attention, to the HFE and the leakage. I bet you won't hear any difference between HFE 50 and HFE 100.
Just try them in your fuzz and listen, trust your years, they are the best measurmenet device! At the end, the same ears will be judging your sound in the crowd and not multimeters.!

i could definitely tell you by ear whether a ge trans is a 100 vs. a 120.

I disagree.

I can clearly tell the difference between the different transistors types, but HFE 100 and 120 I don't know. And keeping in mind the gain changes drastically with the temperature. Yes there is a bog difference in sound between transistors with HFE 30 and HFE 100 I must admit. But maybe it's me or my ears!

[Brymus]

I couldnt tell any difference between 100-120Hfe last night when trying them in my Si Tonebender.(3 transistors)
And most people would say I have dog ear hearing.
I could tell a difference when they were all changed by 20-30Hfe  but not changing the value of just one Q by 20 Hfe.
Maybe in a FF they would have more impact with a change like that.
Also as far as I could tell the ones that tested leaky didnt sound any different than the ones with less leakage,maybe because they all tested leaky by the two most used methods,but if you read PRR post on first page the test isnt good for these higher ma devices.
I thought they sounded good in my Si Tonebender,not "Magical" in any way like alot of people seem to regard Ge transistors.
But they were slightly smoother,and made my single coils sound better,than with Si,however I thought they were a little dark with humbuckers.
But then I was using them in a pedal made to compensate Si Qs to sound more like Ge versions.
I will try them tonight in circuits made just for Ge and report back results.
I recorded all the data from my testing and posted links to it in this thread > http://www.diystompboxes.com/smfforum/index.php?topic=82895.0
Also the collector is in electrical contact with the case,so they need to be insulated/isolated when using, against shorting the collector to another condutor.
But otherwise I am pleased with the sound they are getting.
Bryan

[mac]

Toshiba 2sa49, 2sa52, 2sb54, 2sb56 very common germs in the past, low leakage, ideal hfe for FF and TB and many other projects.

mac

[Brymus]

Thanxs Mac.
I ordered another batch of NPN Ge from Gordelux04, if he sends me the right ones along with the PNPs I ordered previously I will give him a good recomendation.
I had hoped by ordering another lot he would realize I am not trying to scam him.
As it is I think he is refusing to admit he made a mistake and sent the wrong lot of PNPs..
Even after I showed him which lot he sent me, 
He has a huge selection of Ge transistors at good prices,if you dont mind waiting 3-4 weeks for them.
I will post back how this turns out,since alot of his customers are forum members here.
Bryan

[mac]

I do not want you to envy me... but I have to walk only 8 blocks to buy jap germs at less than a dollar 

mac

[MissionBrown]

I've bought a bunch from him (Gore) and they do vary wildly but they're still useful in fuzz and booster circuits.
It means a lot of messing around with biasing, but they're not toal duds.
With measuring HFE and using the small bear method they seem to be very sensitive to temperature variations.

I have another type (Can't remember at the moment, but the're PNP 308 something...) from him with low gain (around 40hfe consistently) and they're great for fuzz face circuits.
Even got them going in a Fuzz Factory clone I built for a friend.

Have them in an easy face I made on strip board and am very happy with the result.

[MissionBrown]

So this thread inspired me to breadboard a GT404b FF.

The schem I used is from the NPN section of http://fuzzcentral.ssguitar.com/fuzzface.php
I used trimmers instead of fixed resistors.
So far I've found Q2 is well balanced at 2.4k but Q1 seems to vary a bit currently I'm set at 5.6k but on another I'd set it closer to 4k
Actually so far the three I've tested as Q1 sound fine at about 4k I did notice a difference in the distortion from transistor to transistor.
This was easily set correctly with the trimmer.

These transistors don't seem to be particularly loud but I think they'll be fine in a FF clone.

Having never used a "real" fuzz face, does the fuzz pot kill your top end when turned down?
That's what seems to be happening to me.
Having said that, I do like the fuzz that I get at maximum.

[MissionBrown]

I went through about 40 GT404's on my breadboard last light.
Some were better in Q1 than others, but the sound was pretty good for all of them despite the inconsistent quality of manufacturing.

I got more or less the same fuzz regardless of which pair I used.

There were some pairs which did immediately sound better than others, so I've marked them as such and taped 'em together for later use.

[juansolo]

I got 20 GT404b's, and using RGs method, the leakage on them is 100uA-250uA, hfe is 50-110. One has low hfe of 15, and one has leakage of 305uA.  This was at around 18-20 C.
I haven't built anything with them yet, which is the ultimate test, does it sound good?

Built a Mk.II tonebender today, sounds great. Added a 47k pot for the bias,  lots of usable tones at either end of the ranges.

[Brymus]

So far I have only tried them in my TB MKII pro ,which was tweaked for Si Qs but still they all sounded good,even the ones with "high leakage"
I think the "smoother tone" can be atributed to the lower gain,as all of mine were under 130Hfe.
Still they sounded really good to me.
I am going to try them in some other circuits as well including FF and Rangemaster.
I am also going to do a blind sound clip test comparing the Ge vs Si,but just so much on my plate right now havent got to it yet.

FWIW
I ordered some more NPN from Gordolux04 over two weeks ago almost 3 now...
He takes forever,I will post back if he made right on sending me the wrong batch on my first order when they arrive.
I am expecting him to have sent some proper PNPs to make up for sending me the wrong lot.