real or fake germs??

[fuzzy645]

Several examples below:

NKT275 OC77 OC84: http://www.ebay.com/itm/3x2-NKT275-OC77-OC84-GERMANIUM-Transistor-set-for-Clone-FUZZ-/310427587098?pt=LH_DefaultDomain_0&hash=item4846ed121a

OC76: http://www.ebay.com/itm/220699583113?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

OC81:  http://www.ebay.com/itm/MULLARD-GERMANIUM-TRANSISTORS-OC81-x4-/170932759546?pt=UK_Sound_Vision_Other&hash=item27cc62ebfa

AC128: http://www.ebay.com/itm/100-germanium-transistors-AC128-PNP-NOS-TUNGSRAM-/310493365290?pt=LH_DefaultDomain_0&hash=item484ad8c42a

Just curious if there is anyway to tell tell real vs. fake?   

[R.G.]

Multimeter.

The forward voltage of germanium junctions at a few milliamperes is about 0.2 to 0.4V. The forward voltage of silicon is about 0.5 to 0.7. Compare the forward voltage. A resistor of 4.7K to 10K in series with the junction and a battery tells the tale. Many multimeters have a "diode" setting in the resistance ranges. Test a known silicon junction and see what it says for silicon. Then try the unknown.

That will tell you if it's germanium (well, or schottky, for diodes, but I don't know any schottky bipolars) or not. Whether it's actually the type number presented is still at question.

Given the sheer number of frantic DIYers ad boutiquers as well as semiconductor scammers scouring the world for germanium transistors, the chances of them being counterfeit on ebay is large. Buy only the amount of money you can afford to lose entirely, then be happy if any of them are useful.

Better to buy from a known and reliable source, such as Small Bear.

[electrosonic]

I would only buy germaniums in unopened packs off of ebay. That random lot of 100 transistors might be leaky discards that someone else has gotten rid of. If it says they are "untested" that probably means the seller has not tested them, someone in the past could have tested them and disposed of them only for them to surfaced on ebay.

Are there instances of fake germaniums? I just thought that crappy ones turned up regularly on ebay.

Andrew.

[LucifersTrip]

if sound is #1 priority, don't be suckered thinking the original # transistors used in the original circuit are best. there are literally 1000's of different germanium transistors out there, so the chance those exact #'s would sound best to you is almost nil

edit:
that being said, here's info on the ac128. there's probably similar info on many of the other popular ones.
http://www.jacquesstompboxes.com/ac128.htm

[brett]

Hi
The 'famous' types of devices are famous by association with the artists of the 1960s. Of course they could (and did) thow away dozens of bad pedals in order to get a good one.
The transition to quality devices came in the 1970s (when Europe and America gave up making them).
The best germaniums by a mile are Japanese and Russian. They are basically 99 or more % good. Negligible leakage, low noise and cheap. Try some GT308Bs for example.
cheers

[Kesh]

As another thread showed, Germaniums that are too low hfe for Fuzz Face and similar may be great for a Harmonic Percolator.

I have bought both 60s western Germaniums and 80s Soviet off ebay uk, with good results.

[Arcane Analog]

Any transistor you buy on eBay is a roll of the dice. The expectation should be that the some or all of the devices are probably garbage. I would agree that the Russian and Japanese devices are generally low leakage. You will need to research the typical gain range of each device to maximizes the chances your purchase will yeild ranges you can use for the circuit(s) you are planning on building. But why bother?

Small Bear has a great selection of germanium and they are audited and screened for the purpose of building a specific circuit. If I am not mistaken, SB's policy is that the device(s) are returnable if they turn out to be hissy (etc) if they are unsoldered. You cannot beat that.

[fuzzy645]

Thanks for the info guys.  Thanks RG for the tip on checking to see if they are indeed germanium trannys.

I'm definitely not hung up on the old names/numbers, but I also don't mind taking a gamble once in a while on ebay.  However, IF doing so, I was hoping there is some way to authenticate these devices.   

The tip about purchasing an unopened/sealed bag sounds good.   I have noticed on ebay very frequently people are selling entire bags  of Tungsram AC176's or AC125s supposedly NOS.  Perhaps they have a scam going with forging the bags too.  Its just tough to trust any of these sources.

[midwayfair]

There's also the heat test. Measure the HFE and stick your finger on it. If the hfe steadily rises (it's actually the leakage increasing), it's germanium. Silicon won't do that because your finger isn't a couple hundred of degrees.

You can do the heat test with diodes, too. It's much more reliable than just the Fv.

I would trust a known seller with small numbers of transistors like the Red Dot (but not white dot) NKT275s selling them at a price point similar to Smallbear's (as in, not gouging/hyping and not too good to be true) enough to take a *gamble* on an E-bay purchase if I were dead set on getting a particular part number. But I'm in the same camp as Luciferstrip. Why spend so much on sought-after transistors that have been sorted out for 30-50 years, when there are hundreds of part numbers that sound just as good that most people have never heard of?

[LucifersTrip]

The best germaniums by a mile are Japanese and Russian. They are basically 99 or more % good. Negligible leakage, low noise and cheap. Try some GT308Bs for example.

agreed...a higher % of Japanese and Russian ones have lower leakage, but remember that certain circuits need leakage to work well. For example the GT308B will not work in an FZ-1 (or the many variants) without making alterations and will not work well in all positions in a MKII (or the many variants), which the op, fuzzy645, is building.

Small Bear has a great selection of germanium and they are audited and screened for the purpose of building a specific circuit. If I am not mistaken, SB's policy is that the device(s) are returnable if they turn out to be hissy (etc) if they are unsoldered. You cannot beat that.

again, that's great if you want to make on-offs, but defeats the whole purpose of DIY...experimenting, learning and figuring out the stuff on your own...

[Arcane Analog]

The best germaniums by a mile are Japanese and Russian. They are basically 99 or more % good. Negligible leakage, low noise and cheap. Try some GT308Bs for example.

agreed...a higher % of Japanese and Russian ones have lower leakage, but remember that certain circuits need leakage to work well. For example the GT308B will not work in an FZ-1 (or the many variants) without making alterations and will not work well in all positions in a MKII (or the many variants), which the op, fuzzy645, is building.

Small Bear has a great selection of germanium and they are audited and screened for the purpose of building a specific circuit. If I am not mistaken, SB's policy is that the device(s) are returnable if they turn out to be hissy (etc) if they are unsoldered. You cannot beat that.

again, that's great if you want to make on-offs, but defeats the whole purpose of DIY...experimenting, learning and figuring out the stuff on your own...

OP is making a MKII and having a few difficulties. A Small Bear Tone Bender set would be perfect to build a first MKII. There is plenty he/she needs to learn before getting into buying random germs off of eBay. Russians/Japanese would never get her/him there without alot of trouble. Recomending those transistors at this point is not a great idea in my opinion.

[fuzzy645]

again, that's great if you want to make on-offs, but defeats the whole purpose of DIY...experimenting, learning and figuring out the stuff on your own...

That is the reason for my inquiry. I would like to try/experiment with a few different tranny's to see how they sound but I don't want to get scammed.

OP is making a MKII and having a few difficulties. A Small Bear Tone Bender set would be perfect to build a first MKII. There is plenty he/she needs to learn before getting into buying random germs off of eBay. Russians/Japanese would never get her/him there without alot of trouble. Recomending those transistors at this point is not a great idea in my opinion.

I do know a prepackaged set from Small Bear would be great and the quickest way to go, but to some degree will take some of the challenge out of it for me, even if it is the best approach.   I would to try out several different type of tranny's and see what sounds the best.   Maybe what I'll learn first hand is that type/brand of tranny doesn't matter but certain range of gain/leakage value is the ticket.   I need to hear it with my own ears.   I know that's not the most cost efficient approach, but I'm sure I'll use the left overs on my next build

[Arcane Analog]

again, that's great if you want to make on-offs, but defeats the whole purpose of DIY...experimenting, learning and figuring out the stuff on your own...

That is the reason for my inquiry. I would like to try/experiment with a few different tranny's to see how they sound but I don't want to get scammed.

OP is making a MKII and having a few difficulties. A Small Bear Tone Bender set would be perfect to build a first MKII. There is plenty he/she needs to learn before getting into buying random germs off of eBay. Russians/Japanese would never get her/him there without alot of trouble. Recomending those transistors at this point is not a great idea in my opinion.

I do know a prepackaged set from Small Bear would be great and the quickest way to go, but to some degree will take some of the challenge out of it for me, even if it is the best approach.   I would to try out several different type of tranny's and see what sounds the best.   Maybe what I'll learn first hand is that type/brand of tranny doesn't matter but certain range of gain/leakage value is the ticket.   I need to hear it with my own ears.   I know that's not the most cost efficient approach, but I'm sure I'll use the left overs on my next build

I am all for it. But the germs the kind folks above were recomending - the Russian and Japanese - are not going to help you learn how a MKII circuit works.

The whole point of buying from Small Bear is that you will not get scammed. Buy a rough sorted bag of germs. Lots of different kinds and parameters. Done. Or go buy a bag from a random guy on eBay and hope you get a few useful devices.

[Arcane Analog]

Oh - I would wager that all of those germs you listed are not fake. Picked over is another question entirely.

[Humboldts Finest]

A couple of years ago I bought some matched germs from this seller. 2n404s and a few others. They tested at home as advertised. Nice guy too, always included a broken English hand written note in the packaging, FWIW

[LucifersTrip]

I am all for it. But the germs the kind folks above were recomending - the Russian and Japanese - are not going to help you learn how a MKII circuit works.

I just want to make it clear that so far I haven't recommended anything (yet) and Brett only recommended the Russians because of low leakage. Those would be great for many fuzzes that don't need leakage.  Obviously, buying a MKII set from Small Bear (or anybody) won't help you learn either. Their bulk lot of 30 for $90 I really wouldn't recommend either, since the gain range specified is 30 - 200+, which would probably put too many out of the "good" range.
http://www.smallbearelec.com/servlet/Detail?no=118

Or go buy a bag from a random guy on eBay and hope you get a few useful devices.

The trick is to not buy from a random guy on eBay. Look through posts here for recommendations. I can personally vouch for this guy:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370510158187&ssPageName=ADME:L:COSI:US:1123

I've bought from him numerous times, we've had numerous conversations and I convinced him to pick up a Peak Atlas for measuring. In addition, these (1T308V) are a better (military) version of the ones Brett noted. The gains are mainly in the 60 - 80  range with hardly any leakage...so, again, not great for the MKII. You can get 40 for $21.50. Good for lower gain Fuzz Faces, Fuzz Rites, Rangemasters and any variants of those.

For ones with a bit higher leakage, yes, the Japanese ones generally are cheaper and have lower leakage than US ones. Look through datasheets or get recommendations from others here for ones that have good hfe ranges (70-150), then try to purchase em in lots for no more than ~$2-3 each.

For instance, a 2SB175 Jap is a pretty common one with good specs. Here's a good data archive that has a lot of vintage stuff
http://transistor-spravochnik.ru/description/2sb175/10315

It's best to buy from a generic electronics store with old stock rather than someone who knows pedals...or you'll have a higher chance of them being picked through.

[Kesh]

I can recommend this guy for soviet germs

http://myworld.ebay.com/gordelux04/&_trksid=p3984.m1439.l2754

[Arcane Analog]

There is a huge thread on germanium transistors. Read that OP.

[pinkjimiphoton]

AC128: http://www.ebay.com/itm/100-germanium-transistors-AC128-PNP-NOS-TUNGSRAM-/310493365290?pt=LH_DefaultDomain_0&hash=item484ad8c42a

Just curious if there is anyway to tell tell real vs. fake?   

fwiw, i have bought these from this vendor, and had great luck. the hfe is a little high, but very nice transistors, and they sound great.

[brett]

Hi

I can recommend this guy for soviet germs

http://myworld.ebay.com/gordelux04/&_trksid=p3984.m1439.l2754

+1 (Have bought hundreds off him. They are in unopened cartons. Typical Russian quality - the best.)

Yes, a few circuits require leakage. But if I'm not mistaken, leakage can be predictably and almost noiselessly simulated with a resistor from collector to base. Yes? Around 470k simulates medium leakage? Or am I missing something?
cheers