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

[Silver Blues]

There probably is, honestly I should know more about inductors considering I'm a ham but it's all eluding me  As for the values:

[Pavlos]

ok, over the festive period I managed to get a few boards put together using the germanium goodies I got from our Bulgarian friend a few weeks back, and the results after a bit of experimentation are....


http://tagboardeffects.blogspot.co.uk/2012/04/sola-sound-tone-bender-mkiii-3-knob.html
Sounds really good, fuzz control is useable all the way from zero (a bit gritty) all the way through to huge gobs of compressed sustain, reacts well to guitar volume to clean things up especially from about 20% and upwards. Tone goes from fat and chewy through to bright snarl without ever getting out the ice picks. Definitely going to get boxed :o)
Q1   MP20A hfe 62 leakage 0.04mA
Q2   MP20A hfe 59 no leakage
Q3   AC125 hfe 124 leakage 0.23mA
Diode  D9B


http://tagboardeffects.blogspot.co.uk/2012/02/sola-sound-tone-bender-professional.html
Sounds similar to the MkIII above but without the tone control comes accross as a bit more muscular and aggressive, this one purrs and roars! sinilar vein to the MkIII but different enough to earn a box :o)
Q1   MP21A hfe 62 no leakage
Q2   MP21A hfe 50 no leakage
Q3   MP21A hfe 65 leakage 0.04mA


http://tagboardeffects.blogspot.co.uk/2013/02/prescription-electronics-yardbox.html
Again, it fits nicely in the same ballpark as both of the above but still brings it's own special something to the party. The fat and chewy is a subtle but noticeabley different flavour to the others and the snarl is that of a different beast too, and as per the descriptions mentioning the esteemed mr Page I'd agree that this one definitely has some strong hints of early Zeppelin lurking under the controls, another one that has earned a box :o)
Q1   MP20A hfe 58 no leakage
Q2   MP20A hfe 55 no leakage
Q3   MP20A hfe 89 leakage 0.06mA
Diode  D9B


http://tagboardeffects.blogspot.co.uk/2014/03/earthquaker-devices-hoof-fuzz.html
Works nicely from a bit of grit to ripping your face off levels of gain, and with a bit of juggling of the shift and tone controls it can go from a blizzard of furious razors through to the deepest roar of doom. Definately sounds more fat and rich (70's?) than the TB variants so far and is another one that will find a box, though I might well experiment a bit with the LED pairs first to see how it affects things (I'm assuming that the way they light up that they are clipping diodes)
Q1 3904
Q4 3904
Q2 MP38 hfe 55 leakage 0.04mA
Q3 MP38 hfe 55 leakage 0.04mA


http://tagboardeffects.blogspot.co.uk/2012/02/marshall-supa-fuzz.html
Good and very close to the MkII above, in spite of a lot of swapping transistors though it just isn't quite as good for me and therefore narrowly misses out on a box.
Q1   MP21A hfe 49no leakage
Q2   MP21A hfe 63 leakage 0.04mA
Q3   MP21A hfe 62 leakage 0.04mA


http://tagboardeffects.blogspot.co.uk/2014/07/dam-fz-673.html
Another one that misses out on a box. Getting a good balance of transistors took a lot of work but was worth it (Was the first of this group that I checked and helped me a lot with dialling the others in a lot more easily) some very good sounds, but no matter the mix of transistors or setting of the trim pot and controls there is always a something splatty/gated limiting how genuinely useful it is for myself. Possibly one to re-visit in future
Q1   MP20A hfe 52 no leakage
Q2   MP20A hfe 54 leakage 0.06mA
Q3   MP20A hfe 72 leakage 0.04mA


So that works out at 4 solid hits, a near miss and an interesting aside, so positive result  though I still have a load more to attempt on my wish list (Buzzaround, Carlsbro, a few hybrids etc) which should keep me busy for a while, I'd say germanium has definately found a place in my arsenal of growlynoiseboxes

[Travis]

Good stuff Pavlos! So which one is your favorite?

If you decide to revisit the Marshall Supa Fuzz, notice that although it is the same circuit as the MKII Bender, it has the resistor values from the OC75 version of the MKII. The MKII that you built from this site is the OC81D version which generally works better with lower leakage, and the OC75 version generally works with more leakage.

The FZ-673 is based on the Zonk Machine, which, along with its cousins the MKI Tone Bender and Maestro FZ-1, is really picky about transistor selection. Most transistor combos are either crackly/sizzly or gated and farty. When you get the perfect transistor set, get ready for some fun stuff, especially with a cranked amp.

I have a DAM FZ-678 which is the third version of the FZ-673. David only made 5 pieces so there is pretty much no info about it on the internet, but it seems like he changed the tone control to a low pass filter at the output. These things are pretty refined, and the resistor values are chosen for the transistors used. It's almost futile to try and clone the FZ-673 because it's so custom, I have better luck going back to the start (FZ-1) and tweaking to taste. Use a 9V like the MKI, change resistors, caps, transistors. It's fun.

[SpaceCommandant]

Travis, regarding your last paragraph about the 673, do you have any specific advice on resistors/caps/voltages to aim for, etc? I've played around with my build and settled on the 'perfect' sounding transistors only to plug it in another day to find that the character has changed: less defined texture, spitty decay, etc. Bizarre, but probably related to temperature changes from day to day. Sounds amazing when it's working perfectly though, so I'd love to one day cage this finicky beast.

[Pavlos]

I've done a bit of reading up on the FZ-673/Zonk Machine and as you say it seems pretty picky about transistors, some combinations I got almost nothing useable other than gated splats, but mostly it was a relatively smallish sweet spot of about three or four notches of travel on the controls before it all starts to go awry, set I have in there at the moment gave me the best results and widest range but yep, crackly/gated and farty are always lurking a slight turn of the knob away on my build. Definately not dissapointed though because with it's lineage and me using different spec transistors I wasn't expecting it to be too easy (Started by testing a challenging one lol) best thing is that it works, got some good sounds and I know that with patience and the right parts it could be even better. Makes sense to have a go at the FZ-1 though, oops, that'll be another one on the list though from what I can tell from all the posts on here and over at FSB there are nearly as many Maestro/TB variations as there are pedalsstill, it gives us all something to do lol

The Marshall Supa Fuzz was the second one I tested and worked well from the off, tried the MP20A, MP21A and the AC125's in a variety of combinations until I settled on that particular mix of MP21A's and it was all set to go near the top of the list to be boxed until I started to check the MkII that is. Then it was like 'you've tried the rest, now try the best' don't get me wrong, the Supa Fuzz is really good, and I'm chuffed to bits with it, but trying them back to back, the MkII just edges it for me :o)

No real favourites of the other four though, even though three of them are TB variants they all have their own thing going on and would suit different uses, with the extra tone shaping available the MkIII and yardbox are probably a bit more versatile than the MkII, but like having the good selection of tools in a workshop, you might be able to use a few different ones to do particular task, but there is always one that is just right for the job, and that MkII is the perfect tool for a few jobs. Now all three in a big box could be interesting Very impressed with the Hoof as well, a lot of good sounds with plenty of character and responds nicely to playing dynamics and the guitar controls but I might hang fire on boxing though because the Tone Reaper is also on my wish list (Board cut ready) so I might just go the whole hog, add a Tentacle and box up a complete Hoof Reaper

Oh and by the way, I know I keep saying it, but thank you all for the help and encouragement, very much appreciated

[Emil]

Hi!

I just started to look into germanium transistors and recently got my first ones.

First up is a bunch of mixed older used transistors that I won in an auction. Mostly of the OC-type. I got the germanium tester built, and here's what I've got:


Transistor: Hfe (Leak in mA)

Mullard Oc71: 84 (0.226)
Mullard Oc71: 39 (0,194)
Valvo Oc71: 22 (0,073)
Mullard Oc71: 37 (0,141)
(Unknown) Oc71: 39 (0,133)

Valvo Oc76: 102 (0,129)
Valvo Oc76: 124 (0,072)
Valvo Oc76: 103 (0,105)

Mullard Oc72: 26 (0,064)
Mullard Oc7? (probably 2): 16 (!) (0,048)

Tungsram Oc1071: 49 (0,088)
Tungsram Oc1071: 42 (0,105)
Tungsram Oc1071: 23 (0,084)
Tungsram Oc1071: 44 (0,129)
Tungsram Oc1071: 53 (0,117)

Valvo Oc75: 47 (0,202)

2n345: 92 (0,016)

Telefunken AF105: 50 (0,101)

I also have a few that just got weird readings, so they might be broken. That includes a Telefunken AF105, Telefunken OC1072 and one that can't be identified anymore.

I was quite happy with those OC76:s! That first OC71 with alot of leakage might be nice in a Tonebender if I've understood correctly? A few others look interesting too. .

Any build suggestions?

Next up for testing are a bunch of Hitachi 2SB89, 2SB75 and 2SA34:s .

[bogey]

Hi there,

I posted a similar question a while back for build suggestions and the advice I got was to try a fuzzface or rangemaster.

Never got round to the fuzzface(but will do someday) but the rangemaster sounded really good until I boxed it and it died....gonna revisit that sometime.

[Travis]

Most likely a grounding issue or bad joint there Bogey

For the lower hfe OC71 try those in a Carlsbro Fuzz or Fuzzrite Q2

The others should be pretty versatile. The OC76 tend to be awesome for MKIII/MKIV Tone Benders. The ones you have should all be good for Q3, but you gotta use your ears. The numbers alone don't tell you what's best of course

[bogey]

Yes Travis that could well be the case ,but I also built it with the voltage inverter and the version with all the different caps wired to a rotary switch which were both a first for me at the time and I just didn't know where to start debugging.

I'll have to have another look at it someday because I really liked it .

[Emil]

Thanks! That Carlsbro looks very nice :).

[Emil]

Got the Hitachi transistors tested now. They were a few more different kinds than I remembered.

2SB79 (13 pieces):
Pretty nice results. The majority around 70-80 hfe , and a couple around 90 and 100. Lowest value was 40 hfe. Leakage pretty much all in the 0.150 - 0.200 region.

2SB75 and 2SB77 (Two each):
Hfe:s around 30-40 and leakage around 0.100.

2SA12 (9 pieces):
Not terribly exciting. Around 20-30 hfe for these, but basically no leakage at all. One of them stood out with 52 hfe, and 0.500 leakage (!).

2SA34 (with four legs) (3 pieces):
Very different results here. One was 30 hfe with no leakage, and one was around 140 hfe with 0.100 leakage. The last one seem to be faulty.

2SA350, 2SA352 (total 13 pieces):
These were giving me weirdly high readings. And they seemed quite unstable or sensitive, as they change from time to time. Might try to test them again.

[Sensei Tim]

So I was all proud of myself for having the discipline to stay away from all of this germanium transistor business for th last 4-5 years....until now.  I got an order for a germanium fuzz and now I have a bunch of  gt404 and gt402 Russian germaniums on the way.  So long, pocket money lol.

[rocket88]

Good luck with the GT404's. I got some once, and only once because they were just a waste. Low hfe stupid high leakage. If you need NPN germanium go for the MP38, I specifically hunt for MP38A cause I found them to be more consistent, and well the last 3 times they seemed to vanish honestly it was my fault cause I bought the sellers comeplete stock, which wasn't a huge amount btw. GT402's are nice, I prefer the GT402V, but now they're harder to find and more expensive cause they have higher gains, similar to the GT402B, which I've seen for NOS NKT275 money before. What Fuzz did you get an order for?

Also, as leader of the germanium deathstar welcome. I've got to find you a good position.

[Sensei Tim]

A Gemini iii fuzz

Should be fun!

[moda]

Evening all or morning depending where you may be.
Anyone have any experience with 2n1302 npn germs? Mp32 have been my go to for the last 6 months but starting to look around for something different.
Hfe is min 20 which is not great but still curious.
Cheers.

[Travis]

I have Texas Instruments 2N1302. They are low leakage NPN, hfe tends to be way above the minimum in my batch but that will vary a lot. The 2N1308 has the highest hfe minimum, then for 2N1306, 2N1304, 2N1302 the minimum is progressively lower. The 2N130_ with an odd number at the end are the PNP counterparts

[moda]

Hi mate. Have you tried any yet? Just dont want to buy a bag and end in tears!

[Sensei Tim]

i've got some 1306's in a buzzaround type circuit and they're great! i just randomly picked 3 out of the bag and used them.

[Travis]

Yes I have been using them for years. I have used them in many different circuits with great success, but not where leakage is necessary. They are not my favorite transistor for everything, but they tend to be my go to NPN germs especially for more modern designs like BJFE stuff

With that said, part of the nature of buying untested parts is that I don't know what you will get. You could get a bag of all minimum hfe trannies, I really couldn't tell you with any certainty. I have had good luck but I suspect that there must be low hfe batches out there

[moda]

Thanks Travis, nice to know. Might go buy me a bag and see what they are like