russian ge-transistors

[mat]

IIRR I did read something about additional internal resistance of the russian germanium transistors. Is this the case and how should I change for example the fuzz face or rangemaster circuit to take this on acount ? Or is it something not to bother about ?

Another question is does the FF temperature stabilazion ge-diode go from Q1's emitter (cathode side) to base  of a positive ground PNP circuit ?

Thanks,
Matti T.

[petemoore]

Or is it something not to bother about ?
  IIUC it throws of the gain/leakage test, and the ones I had read no gain on my little DMM.
  And the pinout was funny.
  Once in the TB and FF and RM circuits all that 'nonsense' [I saw no sense to over-scrutinize a good thing] seemed to wash away with nice bias, great sound. OCourse, AYKnow, YMMV.
  Another question is does the FF temperature stabilazion ge-diode go from Q1's emitter (cathode side) to base  of a positive ground PNP circuit ?
  The diode in the transistor circle indicates the direction of the TStabilization diode, it goes opposite polarity and parallel to the B/E diode. It's supposed to help thermal runaway by reducing the amount of current through the transistor.
    I seem to recall the TSdiode being measured and chosen for a foreward threshold voltage which matches the transistor used, [check back to see how others remember it. I did that, installed it, and it seemed to help, I questioned my own observations on that one, and left the diode in there, and have had fine bias-luck with good transistors in FF's.
  And have had really cold Ge's that bias-gate...I just use an opamp or BMP distorter until they warm up.
 

[mat]

it throws of the gain/leakage test, and the ones I had read no gain on my little DMM.

You mean I cannot test these with R.G.'s tester ?

And the pinout was funny.

Yes, luckily I have datasheets that shows which leg is what.

Once in the TB and FF and RM circuits all that 'nonsense' [I saw no sense to over-scrutinize a good thing] seemed to wash away with nice bias, great sound.

What transistor(s) did You use for Your FF ?

Another question is does the FF temperature stabilazion ge-diode go from Q1's emitter (cathode side) to base  of a positive ground PNP circuit ?
  The diode in the transistor circle indicates the direction of the TStabilization diode, it goes opposite polarity and parallel to the B/E diode. It's supposed to help thermal runaway by reducing the amount of current through the transistor

.

I'll take that as yes then 

I seem to recall the TSdiode being measured and chosen for a foreward threshold voltage which matches the transistor used, [check back to see how others remember it. I did that, installed it, and it seemed to help, I questioned my own observations on that one, and left the diode in there, and have had fine bias-luck with good transistors in FF's.

How did You compared the diode to the transistor, I mean what was the attribute on the transistor that should be measured ?

And have had really cold Ge's that bias-gate...I just use an opamp or BMP distorter until they warm up.

Thanks petemoore for Your answers !

[skiraly017]

I've played with a bunch of the Russian GE's and have had very good results. Rely on your ears for these and I think you'll be pleased.

[snap]

they`re said to grow whiskers!

[rnfr]

check this out.  i think it sounds fantastic.

http://www.aronnelson.com/gallery/main.php/v/rnfr/DIRTY+BOOTS/DIRTYBOOTSV3_3SCHEMPRINT.png.html

[rnfr]

oh yeah-
the GT308A's i used are BCE top to bottom.

[mat]

I've played with a bunch of the Russian GE's and have had very good results. Rely on your ears for these and I think you'll be pleased.

So it would be just issue of biasing them 'right' then. I've also built two FF's usin ru-ge-trannies. I like them alot but was just remembering of reading something about additional internal resistor they have..

[mat]

they`re said to grow whiskers!

Well that is it ! I'll definitely will use them 

[mat]

check this out.  i think it sounds fantastic.

http://www.aronnelson.com/gallery/main.php/v/rnfr/DIRTY+BOOTS/DIRTYBOOTSV3_3SCHEMPRINT.png.html

rnfr, do You have soundsample of this one ? Is it more a fuzz or overdrive ? When I have time I will breadboard this one, thanks!
Btw. one minor thing - C8 says 100k, I think it should be 100uF.

[mat]

I found interesting reading about the subject:

http://www.diystompboxes.com/smfforum/index.php?topic=63549.0

Would be really cool to know which transistors (if all) has the internal resistor 

[rnfr]

yeah that should be 100uF.  sory about that.  and another thing, i used gt131a's not 308's.  i made it in order to fill in a gap in my board for am overdrive.  i have a loud clean amp and i wanted somthing that i could keep on all the time if i wanted to.  it's really a dirty boost- meant to drive the front of your amp and add some dirt on top ass well. it's crazy loud, and can get into fuzz territory with hot pickups.   i found that with the bias arrangement the way it is, i liked to add a 100k resistor in series with lug 1 and the 9v rail.  it stopped there from a dead spot at either end of the pot's rotation.
  what really inspired me to build this, is that i'm never really satisfied with diode clippers, and wanted to make a germanium pedal that was an overdrive. no samples yet, but give it a shot, it sounds great!

[mat]

Thanks rnfr for the info !

Matti T.

[rnfr]

here's a vero layout for ya too.

http://www.aronnelson.com/gallery/main.php/v/rnfr/VERO/DIRTYBOOTSV3_3VERO.png.html?g2_imageViewsIndex=1

[mat]

here's a vero layout for ya too.

http://www.aronnelson.com/gallery/main.php/v/rnfr/VERO/DIRTYBOOTSV3_3VERO.png.html?g2_imageViewsIndex=1

Great ! Big thanks !

Matti T.

[snap]

they`re said to grow whiskers!

Well that is it ! I'll definitely will use them 

http://www.diystompboxes.com/smfforum/index.php?topic=58452.msg585486#msg585486

[rnfr]

that article doesn't mention russian ge's anywhere.  all russian ge's i have measured and read about have had extremely tight tolerances.  don't really know where youre going with this.

[brett]

Hi

all russian ge's i have measured and read about have had extremely tight tolerances.

That is interesting.  It is very unusual to get tight tolerances in Ge devices - even the best of them.  Some of that is due to intrinsic issues with Germanium.  For example, hFE and leakage are VERY temperature dependent.  You can try heat sinking to the max and building in temperature-dependent biasing (e.g. negative feedback to prevent thermal runaway).  But Germanium devices are simply more temperature sensitive than Silicon ones due to its position in the periodic table.  Silicon junctions hold their characteristics until quite hot and don't melt until 150 C (or more).  However, Ge junctions are drifting this way and that at 40 and 50 C (try putting one in RG Keen's tester and put your fingers on it and off it, and watch the readings dance to and fro !)

This is not to say that I don't like the Russian Ge devices.  I think both the 308s and the 313s are terrific!  But I've posted before that they have a considerable range of hFE.  That can be a good thing, too !

cheers
Brett

[snap]

that article doesn't mention russian ge's anywhere.  all russian ge's i have measured and read about have had extremely tight tolerances.  don't really know where youre going with this.

that post is a little related to this one by vanessa, where she first mentioned radiation exposure:
http://www.diystompboxes.com/smfforum/index.php?topic=49776.msg371191#msg371191

[rnfr]

that article doesn't mention russian ge's anywhere.  all russian ge's i have measured and read about have had extremely tight tolerances.  don't really know where youre going with this.

that post is a little related to this one by vanessa, where she first mentioned radiation exposure:
http://www.diystompboxes.com/smfforum/index.php?topic=49776.msg371191#msg371191

but what does that post have to do with russian ge's??? you lost me.