germanium transistor gain too high?

[chromesphere]

Hello!

Quick question, this is the first time i have bought / measured old (prob 70's) russian transistors before and im getting HFE's all over the place. From 50 to 250!  I was just going to ask, are 200+ hfe germanium transistors good or useless?  I have 5 that are 200-250 so far.  Are 200+ gains sort after or useless? Of course the easiest test is to plug them in and test, but just wondering what peoples opinions are on this.

Paul

[John Lyons]

For a fuzz face they may be too high but there are thousands of other circuits that might be fine with them.
The leakage would be a concern al ost more that the gain.

[chromesphere]

Thanks John!

Leakages generally seem pretty good so far.  Usually less then 300, sometimes 300-500.  THere are a couple over 500.

I've built 2 madbean soul benders, and im currently messing around with them to see what sounds good / no good.  Not sure if its just a matter of being a forgiving circuit, but i was surprised to hear how 3 x 40-50 hfe ge trans sounded quite similar to 2x40-50hfe and 1x150hfe transistors.  Didnt sound quite as 'fuzzy' but still sounded pretty dam good!  I was expecting the low gains to sound like nuts.

I'll try some different combos in them, might do a video comparison of a few different set ups while im testing them for curiosities sake.

Thanks again!
Paul

[LucifersTrip]

one of the greatest fuzzes I built was the Marshal Supa Fuzz with 3 high gains per DAM's info.  Here's the MKII Supa Fuzz master at DAM giving some info when someone thought the voltages should be 4.5v like a Fuzz Face:

========================
http://dam.10.forumer.com/viewtopic.php?t=779&highlight=collector+voltage
(a few posts down on the right)

"Not the in a MKII. On vintage units it varies from around -7.6V - -8.9V.
Even seen em with 9.1V! I take measurements with Zinc Carbon batteries which are around 9.6 Volts when fresh. The original batteries used in the MKII's and its variants were PP4's (Eveready 226) which also read high at around the 9.6V level.
Hfe levels are usually higher also. For example my '67 Supa Fuzz measurements...

Q1 - 174
Q2 - 208
Q3 - 194
========================


I used 3 x 2SB459 (leakage < 200mA) with hfe 244, 193, 213 and an external bias pot with trim/cutoff on Q2 collector to give me from -6v to -8.5v on Q3 collector

[chromesphere]

I have quite a few in this bnuch that are 150+ with low leakage so thats good to know they are sort after / not too high gain.  Always wondered if this sort of range was sort after or not desired.  Thanks for the response.  Looking forward to testing one in my soulbender tonight 
Paul

[LucifersTrip]

they're not really sought after since very few vintage fuzzes use em. That Supa Fuzz is the only one I could think of quickly...but with higher gain, usually comes higher leakage and those are used in FZ-1's and variants

[Pyr0]

^^^ Great info - thanks. I've a bunch of high gain, low leakage ASX12D's, must give them a go in a Supa Fuzz.

[LucifersTrip]

^^^ Great info - thanks. I've a bunch of high gain, low leakage ASX12D's, must give them a go in a Supa Fuzz.

I should've noted that you do need some leakage in the Supa Fuzz, so the really low leak Russians wouldn't be cool.
The ones I used were in the 150-200mA range, but you should be able to get away with up too ~300mA (maybe more?). Higher leak in Q2 will cause some gating, which is what many builders consider a part of the actual Supa Fuzz sound.

[chromesphere]

Im pretty sure mine are around 150-300...um, i assume you mean microamps lucifer?  I'll have to look at building a supafuzz next thanks for the info!
Paul

[LucifersTrip]

yes, exactly...typing before thinking...150uA - 200uA+

[chromesphere]

Thanks for the confirmation lucifer!

Hey i wanted to ask you a specific question (as long as it doesnt cost my soul? )

I read something you wrote in this thread and just wanted to clarify.   Were you saying the GT108V wasnt very suitable for Q3 in a tonebender and Q2 in a fuzz face circuit, or were you referring to ALL russian transistors?  

http://www.diystompboxes.com/smfforum/index.php?topic=95485.0

Reason i ask is that i tried a bit of a comparison with some vintage / leaky Russian transistors in a couple of soulbenders VS the GT108V's ("modern") and i honestly couldnt hear a hell of a lot of difference:

Unless the Soul Bender doesnt really care whats in Q3?

Thanks again mate!
Paul

Edit: i can hear the most subtle of differences, the vintage transistors might sound a bit "saggier" but yeah, for me personally the difference is really slight.

[LucifersTrip]

Hey i wanted to ask you a specific question (as long as it doesnt cost my soul? )

hahah...just a few moments

I read something you wrote in this thread and just wanted to clarify.   Were you saying the GT108V wasnt very suitable for Q3 in a tonebender and Q2 in a fuzz face circuit, or were you referring to ALL russian transistors?  

It's never ALL of anything...but I was referring to alot of the common modern (1980's+) Russian ge transistors that a ton of DIYers are buying these days...with very very low leakage ~50uA and less. The 1T308B's actually measure 0uA leakage on my Peak, though I'm sure there's some.

The tonebender needs some leakage (you can read about that more on the other forum). I've tried it in all spots with no success as compared to ones with normal leakage (100-300uA).

For the Fuzz Face and variants, I've found those super low leak ones in Q2 give it a harder, less soft, less saturated & less fat sound...the things that make a FF cool for many...but that's going to be personal taste. In Q2, to me they sound somewhere between a ge and low gain silicon.

Though, I've found those super low leak ones are amazing for darlington pairs or fuzzes that don't have soft, saturated tones, like all the Fuzzrite variants

[chromesphere]

You sir are the google of fuzz.  Thanks for the explanation! 

Some of my GT108V's have 50-100ua of leakage (tested with the smallbear simplified circuit), which might account for the lack of difference fuzz 'texture'.  I'll have to remember to use the old school (100-300ua leak) germs i've got for the fuzz face if i build one.

Thanks again for your help.

Eternal damnation was worth it.

Paul