Great Jumpin Germaniums! (Ge Diode and Transistor Reviews & Discussion)

[rocket88]

so after some much deliberation, some of us thought it would be good to have a thread about the sound of different Ge Diodes and Transistors. here's some of what i've come up with from my own experiences. by all means, add what you've found out, hear, suggest, etc. and ask whatever about these fantastic parts made from a great mojotastic/black magic element.

Ge Transistors:
GT308V, but look for 1T308V (military version) - i've had not great luck with GT308V's most i've gotten are in the 50hfe range, while the military spec 1T308V's are mostly in the 70-90hfe at lest what i've got. they sound great, a little on the dark side, warm and fuzzy, great tone, great in the fuzzface. in fact i only took them out because i tried the GT402V's and just feel in love with those, but none the less great transistors. btw, nothing wrong with the normal GT308V's just mine have never seemed to be as good as others.

GT402V - hard to find, and can be expensive but sound AMAZING in a fuzzface, may be sacrilege to say, but sound very similar to my ears to my NOS Red Dot NKT275's, bright, not to bright, singing sustain, warm fuzzy goodness. side note: i find them to sound best with a bias voltage in the 5-6V range rather then the typical 4.5V.

GT108V - sound sorta like a cross between Ge and Si. they have their own vibe, but really great. a little more on the Si "harsh" vibe, rather then warm, but really lets you cut through the mix. i kinda think of them as if a Ge and Si mated, and you'd get the GT108V. if you see GT309G's or GT309's, they are supposedly the same, or at least sound very similar.

GT109V's - super high gain, i have some that have over 600hfe. they are teeny tiny, and like the GT108's & GT309's they sound sorta like Si to me, and a little noisy. i don't think anyone else has picked them up, or at least said anything about the, but they are usually super cheap so it would be worth picking them up and giving them a try.

MP20A - my #3 go to Ge. warm, well rounded in tone. work great in anything from rangemasters, and fuzzfaces. love these. great in anything. also look for MP20B's, these are higher gain versions, same tone more volume and sustain.

MP16B - just picked these up and some MP16A's. AVOID the MP16A's, they are low gain, despite the datasheet saying they should be up to 100hfe. i haven't tried these in a circuit yet, but the MP16B's are listed as a sub got 2n404's. good in fuzzfaces, i find these make a heavy, thick and gnarly fuzzface.

MP21D - great in tonebenders for Q1 & Q2, and great in fuzzfaces too. big and fat. the gain is usually lower then what they should be on the datasheet, but very usable.

MP41A - NOT MP41. wide gain spread, but sound big and fat. i have 2 with hfe in the 90's in my modified Oracle fuzz, which is based on a MK 1.5 tonebender, and it sounds thick, rich, and heavy.

NPN look for MP38A. they seem to have disappeared, but have almost no leakage and great gains, which is rare for NPN Ge's.

AVOID:
MP35's. i got some and the gains are pretty low, highest were in the 50's. i haven't tried them in anything, so i can't comment on their sound, but have been avoiding it since the gains are pretty low.

also, i know the the joe bonamassa fuzzface asks for  MP39B's. i got some before that came out, but i can tell you most of them had gains in the 40's, so i'm not sure if the ones in the pedal have ones that are higher gain or if it should be that low.

also, i've had terrible luck with GT404's, which are NPN's. i their leakage was so bad i have some over 1uA. supposedly they sound fantastic, but you have to sorta a lot to get a few good ones, and they're expensive.


Diodes:

D310: have a nice, rich, warm distortion to them, close to some of the 1n34a, and mojotastic to look at. they help provide some nuclear power for your pedal

SFD-112: warm and smooth, can get a great fuzziness to them, but the circuit remains very clear, ie: you can here the individual notes while you play.

SFD-111: very similar to the SFD-112. the main difference is they seem to breakup a little earlier, and are a tad less clear. one of my top choices.

i have to find the time to write out a good description of all the others i have, including what i hear from the different D9's.

what i can say as of now i love the D9V's. i think that breakup beautifully and the harder you play the more they breakup, so it adds a lot of life to my playing. to me its like they just beg you to play harder and give it your all. and since they react to your playing, you can easily control the amount of clipping just by controlling your playing.

[Surgeon]

Thanks Rocket... I've never had good luck with Ge transistors for some reason (the GT308s I have don't work in much of anything so far) and purchasing large quantities for very few good ones kinda bums me out...

Great review, I'll keep my eyes peeled for good prices on your top-3!

[rocket88]

i haven't had good luck with GT308's either, it's the 1T308's that i've had great luck with. they're the military version, and seem to have higher gains and are more consistent the the normal GT308's.

always glad to help. hopefully this can get tacked at the top and we all can add info to get a database going. i mean we all seem to be after good Ge parts, so why waste money on bad ones.

[IvIark]

Nice job buddy, an interesting read, hopefully everyone else will add their own thoughts.  I've pinned it

[Vince]

I've had great results with my 1T308b's... I've found that the low HFE's do not matter in a fuzz face. I've dropped a couple of 40 and 80 hfe and it's the same if not higher gain than two AC128's at 120hfe..

There is a video on youtube somewhere explaining why that is.. something to do with frequencies rather than gain values... Measuring them is all good but I prefer to drop them in and hear it....

[Beaker]

Nice work Zach!

I'm with Vince on this as some of these Russian germanium components don't seem to obey the rules. Some transistors work superbly, with a HFE reading that is 80% less than the gain of some layouts suggested silicon transistor . For example I'm getting consistently good results subbing MP38's with a gain of around 60, for 2N3904's with a gain of over 300.
MP20's work great in Fuzzfaces too.

So sod what it says on the layout- try it and see if it works.

[rocket88]

Thanks. Glad we're getting a resource built, especially with such a silly thread name, which credit goes to Heath. I can't agree more about the Russians and the gains, but I can't help be feel like <40 is really too low. I may go back and try them in a fuzzface and see. I can definitely tell you that with the fuzzface when I used gains in the 40-50 range I did have to increase one of the resistors to get more output as it wan unity gain at full clockwise.

Btw, when I read it I just hear it in Doc Brown's voice and laugh.

[glasspak73]

I have a question about OC81-D. I bought 10 off a person on ebay,I want to get the jimmy page zeppelin 2 sound.I built the tonebender mrk2, after many many hours of switching my OC81-D's around and trying AC128 I still cant get that sound.It has wonderfull high gain but there is a sound that goes with the high gain thats missing.this sound is like part raspy and part gated ontop of the high gain.how do i get this? Or what did i do wrong?Can someone?anyone please help???

[rocket88]

If I'm not mistaken the leakage of the transistors, as well as the gains for specific position plays an important  role in the tone. I don't remember what they "should" be off hand, but I would check the comments for the tonebender layouts on the main page, and would see if there's any info about it under the dam version. But, remember it's not just the pedal that will give you a specific sound, it's everything that went with it and connected to it, not to mention the player.

[glasspak73]

Its the sound of the Gary Hurst tonebender mrk2 that im trying to get.i understand different people make up different sounds and playing but the original tonenender mrk2 has that raspy part mixed in with the high gain im trying to duplicate that.most videos I have seen on YouTube of tonenenders don't have that raspy part to them just like mine.im thinking maybe I have fake OC81-D's.where can I get 3 original OC81-D trannies that are matched for this circuit? Or are there other transistors that will male that sound? The chandler limited germanium drive gas that sound also.

[rocket88]

I don't think the transistors are fake. Did you determine the leakage of them, and measure the hfe correcting for the leakage? There's a couple of things you can do. One, order a set of for tonebenders from a company, I suggest smallbear. Two, check to find the transistor specs for the specific tonebender you're after, and try your best to match them. Also, if you have a schematic for the one your looking at cloning check that all the values are the same.

[Chris60601]

If you don't mind paying the price, Mammoth has that part
http://www.mammothelectronics.com/GT-OC81-p/100-gt-oc81.htm

Meh - it may not be the OC81D you are looking for </Lame Star Wars Saying>

[rocket88]

but you have to remember, that if you're going to buy individual Ge transistors for a circuit it's not like Si transistors where you pop them in and you're good to go. you never know what the gains will be, so to get in this case the 3 you want you need to buy a bunch to make sure, and even that you're not guaranteed that you'll get what you want. which is why you should buy them in large lots, and sort them to make sure the gains and leakages and find a set that will fit what you're looking for. in some circuits it doesn't matter, in others it really does. the tonebender is one where it will make a huge difference.

if you don't want to sort for a set look here, and get a pre-matched set. i've bought a Ge set for a fuzzface before i started buying lots of Ge's and doing my own sorting, and what you get from smallbear will work and sound as they should in the pedal they are picked for, ie: tonebender mkii pro set will sound like a tonebender mkii pro.

also, not to get all crazy about mojo and whatnot, but remember that the transistor is a small piece of the puzzle, and in most cases i'ld say don't believe the hype. i mostly use old soviet Ge's, as you can see from what i've listed above, and they sound as good and in some cases i think better then the legendary transistors people are after. the only real exception i've noticed so far is using real NOS red dot nkt275's, short and fat, in a fuzzface, they have a very different sound, seem to have more sustain, and less high end fizz, but that's how i hear them. the reissues, long and skinny, sound completely different, and to me sound like ac128's and a little more generic.  i equate it to this, if you go out and buy a ferrarri it's not going to make you a race car driver, there's more to it then that.

btw, after a little searching i found on fuzzcentral this about the transistor gains for the tonebender mkii

"The transistor gains for the MKII should be something like 70 for Q1 and Q2 and 100 for Q3. The gains don't have to be exact, but it helps for them to be close to these values."

so again, you can't just buy a bunch of Ge transistors and drop them in place and expect it all to work perfectly. there's a little more art to it, and you need to sort and pick the right parts to get what you're after otherwise it will either won't work or will sound like crap.

[Lee Oswald]

Something I'd like to suggest for this thread. Could you guys list good sources
for these Russian parts?

The State thanks you comrades.

[Beaker]

Just had some D311 diodes turn up in the post from Bulgaria. I thought that they would come in a plastic bag, but no, they were in a mint condition sealed cardboard box containing a data sheet stamped 1973. I slit the paper box seal open as carefully as I could, but now almost feel bad for having done it.

Is it just me, or does anyone else get ridiculously excited by un-opened 40 year old cardboard boxes?

Do I need help.....?

[IvIark]

I'm exactly the same.  I can't get rid of the old boxes and so keep them in there.
 
I bought a load of old NOS Ohmite carbon comp resistors a few years ago, maybe 2000 - 3000 and most of those came in sealed boxes of 25 too, and I've still got all those boxes as well! :o)

[rocket88]

Me too, but I had to get rid of all my boxes. I had to get rid of a bunch of stuff cause I had to move in with my parents, since I'm waiting for the original owners of the house I bought to move out. I had to leave my last place, cause i couldn't do a month to month lease. But opening those boxes is like being a kid on Christmas. Not to mention the Russian transistor boxes have just cool typefaces and colors.

[Lee Oswald]

Would someone mind providing links to some of
these Russian sources. I've tried an internet search\
but haven't had an real success.

Are the transistors listed at the start of this thread
those with the Hfe that we're generally looking for
for use in pedals?

[rocket88]

Some are, some aren't. The Russian age transistors don't seen to play be the normal rules for what gain sounds best in certain pedals (who's surprised by that, jk). The big thing is frequency response.

For example, I've built a few fuzzfaces with 1t308v's both with gains around 50hfe. Those pedals sound just as good, have just as much output, and clean up just as well as those with the holy grail gain of Q1:80hfe, Q2:110hfe. I have yet  to try anything lower then 40hfe, but have heard people say they still work just as well. The lower the gain, usually the lower the output, and less fuzz you'll get. In one of the fuzzfaces I built with lower gain, 40's hfe, was super smooth, not as biting as some higher gain ones.

Unlike pedals that use Si transistors. Ge is finicky, the weather and temp can have a major impact on how they work and you the gains will change with temperature changes. What I've done is I look at the gain ranges listed on the datasheet and see if they are in the ranges I'm looking for. You want to experiment with gains, depending on the pedal and see how it turns out and how you like it.

What I posted above is my experience with those Russians, and I will be posting my experience with others too, and hope others post their info. I've bought all of mine on eBay, just search by the transistor name and yell should find stuff, but some are really hard to find , like gt402v and gt402b. Take a look in the thread about the Bulgarian seller we all use (they usually have mp20's and 1t308's available for cheap),I also have had good experience from a seller in Russia, who I forget their name. When I'm home I'll post some sellers that I use and the ones our Bulgarian friend uses.

If you order anything, get at least 50, as you'll need to sort to see what gains and leakage you got, and it gives you a chance to experiment. When I order Ge transistors I usually order them 100 at a time minimum. In fact I'm still sorting my last order, and still have 100 MP16b's and 200 1t308v's I have to sort through.

[IvIark]

Lee Oswald wrote

Would someone mind providing links to some of
these Russian sources.

http://www.ebay.co.uk/sch/bg2014-manue/m.html?_nkw=&_armrs=1&_from=&_ipg=25&_trksid=p3692
http://stores.ebay.co.uk/Orpheus-2005
http://stores.ebay.co.uk/Next-Lux