Author Topic: NOS germanium stock  (Read 414 times)

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Tristano

NOS germanium stock
« on: October 19, 2017, 08:30:33 AM »
I have found a source for NOS germanium transistors. Which of the following list would be the best for guitar fx? The ones marked green I known I'm byuing, and probably the red ones. Any suggestions?

AC107, AC113, AC115, AC121, AC125, AC126, AC127, AC132, AC134, AC141, AC154, AC155, AC156,
AC157, AC165, AC166, AC167, AC168, AC169, AC187, ACY17, ACY18, ACY19, ACY20, ACY21, ACY22,
ACY27, ACY28, ACY29, ACY30, ACY31, ACY34, ACY35, ACY36, ACY40, ACY41, ACY44, AD131, AD133,
AD136, AD139, AD148, ADZ11, AF106, AF109, AF114, AF115, AF117, AF127, AF139, AF179, AF186,
AF239, AF240, AFZ12, ASY70, ASY76, ASY80, ASZ15, ASZ16, ASZ17, ASZ18, ASZ21, AU110, OC25, Oc26,
OC28, OC35, OC45, OC70, OC74, OC75, OC77, OC83, OC84, OC139, OC169, OC170, OC171, OC200,
OC202, 2N174, 2N525, 2N527, 2N711, 2N1302, 2N1304, 2N1306, 2N1307, 2N1308, 2N1309, 2N1558,
2N2147, 2SB405, 2SB407, 2SB492

Resynthesis

Re: NOS germanium stock
« Reply #1 on: October 19, 2017, 08:56:37 AM »
OC83/84 are good for Tonebenders. Dave Main uses 75/83/84 for various iterations of his TBs maybe have a listen to some demos if you're interested in this type of thing.

R.G.

Re: NOS germanium stock
« Reply #2 on: October 19, 2017, 12:08:57 PM »
Just so you're aware of this: The part number on a germanium transistor is only a very crude indication of its usability in pedals. What really matters is actually measuring the gain and leakage of the actual transistor you use. The fallout rate on any given "type number" of germanium devices ranges from about one of every two to nine out of ten bad ones. All the part number tells you is if it's a candidate for use, nothing more.

Also: since pedal makers have been scouring the planet for good germanium fuzz face transistors for over twenty years now, there are a lot of rejects from the measurement and sorting process by all those makers and dealers that are sold as "good for guitar pedals", but they are actually the ones that did NOT pass the testing.

If you know this and plan for it, you won't be disappointed. If you need to be sure you know what you're getting and not just hope you'll get good ones, it's better to buy from someone who pre-tests them for you and supplies only good ones. Otherwise, you're just betting that (a) you found a "virgin", not pre-sorted cache of parts and (b) the ratio of good to bad make it worth the price for you.
R.G.

Quick IQ Test: If anyone in a governmental position suspected that YOU had top-secret information on YOUR computer, how many minutes would you remain outside a jail cell?

BetterOffShred

Re: NOS germanium stock
« Reply #3 on: October 19, 2017, 12:49:31 PM »
^^^ This.   I'm new to the Germanium game, but I think for most of the stuff I'm going to build in the future I'm going to bite the bullet and spend 10$ each and get a measured entity.  I spent 25$ and got a bag of 50 transistors and maybe 5 are useable in guitar pedals, and zero were within the range I actually needed for my project.     

EBK

Re: NOS germanium stock
« Reply #4 on: October 19, 2017, 03:14:31 PM »
What makes a Ge transistor "unusable"?
Do you just mean unusable as a drop in replacement/substitute for a specific circuit?  Or, do you mean that no possible biasing or topology will result in good sound at the output?
No affiliations. If I glowingly mention specific merchants or products, it is because I like them without having to be paid to like them.

BetterOffShred

Re: NOS germanium stock
« Reply #5 on: October 19, 2017, 03:37:47 PM »
I guess for me as a Germanium Noob, I mean that they are far too low of gain to be used in any of the circuits I'm trying to build, or have way too high of a leakage going on.   I don't know enough about changing things in a circuit to compensate for this at this point in the hobby.

Most things I'm interested in specify at least 90 hFe and usually closer to 150, with leakage at or below 200ma (is it micro or milliamps?) 
I got a bunch that are like 35-60 with low leakage, but they don't really sound great in things I've tried them in. 

smallbearelec

Re: NOS germanium stock
« Reply #6 on: October 19, 2017, 10:57:00 PM »
What makes a Ge transistor "unusable"?

In many pedal circuits, parts that are too leaky are difficult to bias and not temperature stable. Low-gain parts are not usable on their own in many classic circuits, but see my comment later on Darlington pairs.

pedal makers have been scouring the planet for good germanium fuzz face transistors for over twenty years now

While I'm a specialty distributor more than a pedal maker, I am one of those who has "scoured the planet". I have a few comments that I hope might help Tristano and some of the other posters here. Please check out this section of my store:

http://www.smallbear-electronics.mybigcommerce.com/bulk-rough-sorted-lots-1/

The lots you see range in price from $2+ to $5+ per device. In all cases, I have sampled the lot and warrant that it has not been "cherry-picked". The difference in price reflects what I had to pay for the particular type, sometimes the relative scarcity (NPN is harder to find than PNP), and sometimes the gain bucket(s)--material in the "magic" 70-150 buckets is always more in demand. If you click on any item title, the details will include my description of the range you can expect to see. If you want a small assortment for sorting your own, this is where to shop. My store and others also offer matched and audited pairs and sets, but those are necessarily more expensive per device.

I got a bunch that are like 35-60 with low leakage, but they don't really sound great in things I've tried them in. 

Those parts may well be usable if you set them up as Darlington pairs. With help from R. G., I did these articles:

http://diy.smallbearelec.com/HowTos/BreadboardRMs/BreadboardRMs.htm
http://diy.smallbearelec.com/HowTos/BreadboardGeDarlingtonFFs/BreadboardGeDarlingtonFFs.htm

With a little patience, you can get some really good results. Don't toss out even your leaky devices; they can find homes in Fuzzrites and Maestro FZ-1As.

I noticed that the list that the OP gave did not include any Russian devices. I now stock some of these:

http://www.smallbear-electronics.mybigcommerce.com/russian/

and suggest that you check them out.
« Last Edit: October 19, 2017, 11:14:31 PM by smallbearelec »

pinkjimiphoton

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Re: NOS germanium stock
« Reply #7 on: October 20, 2017, 08:09:03 PM »
i've bought thousands of npn ge's over the last decade or so, to get maybe 100 useful ones.
that said, there's some KILLER fuzz q's coming out of eastern europe, if ya take the time to get some samples. i found a source that's pretty unbeatable, BUT the pinouts are an unusual ecb. i don't care. i buy them in lots of 100 and pay way less than a buck a piece for them after shipping.
the NOS stuff is usually only good in term of american q's at places that have huge inventory and stock that people don't really know about. one of the guys here on the forum found such a source (haveyouseenhim) and had some really great stuff available, and sent me samples years ago.
but i'd be leary of a lot of online stuff.
even "good" "tested" ge's only mean they meet the specs posted on them at THAT particular humidity and THAT particular temperature.

ge shit is extremely fickle.
a lot of good pnp's out there still, but even more noisy crappy ones.

i prefer the npn's which is what i'm always looking for. i just don't like dealing with the hassle of pedals that need their own power supply or battery. a lot of the 2n404 types from russia are really good and often in useful gain ranges.  shoot for ones with an j k l m or n in the name, those are in the magic  ballpark for fuzzes usually, the a-i ones tend to be a lot lower gain.
digi2t:
"Fuzz, distortion, and wah, are plenty abound. Mutron Flanger, not so much.  8)"
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BetterOffShred

Re: NOS germanium stock
« Reply #8 on: October 20, 2017, 08:16:24 PM »
My man, good points all around.  Thanks for the insight for those of us who are just beginning our Germanium quest. 

I built the voltage inverter for my Skyripper from a Mouser 7660 and it's the bees knees!  You can totally daisy chain it and it's noise free.  I suggest it all around :)
-Brett