NKT275 red dot vs. white dot - is this hype or real?

[fuzzy645]

OK, I was perusing the internet and noticed Analog Man sells these FF clones w/either "red dot" or "white dot" versions of the NKT275. I understand these transistors are quite rare these days, but as I continue googling it seems that most images of these fabled transistors have no dot at all.  Is this dot something Analog Man paints himself onto the transistor after measuring it as low or high gain, or did they really come color coded with dots back in the golden age?   

[Scruffie]

Transistors did have dots painted on them... but if the colour of that dot relates to anything I don't know, it's a collector marker as far as I know.

If they were in a gain bracket they had a second dot painted on them in my experience, but I might be wrong.

It's probably a bit of mojo...

[fuzzy645]

Transistors did have dots painted on them... but if the colour of that dot relates to anything I don't know, it's a collector marker as far as I know.

If they were in a gain bracket they had a second dot painted on them in my experience, but I might be wrong.

It's probably a bit of mojo...

Thanks.  So there is something to it.  What then about all the images of NKT275s with no dots, as well the ones that pop up on ebay selling them with no dots?    Does the absence of a dot provide evidence it is a fake?

For example, here is an ebay seller with excellent feedback selling a lot of 10.  Could it be a fake?

http://www.ebay.com/itm/10-germanium-transistors-NKT275-Fuzz-/380399165339?pt=LH_DefaultDomain_0&hash=item58918e9f9b

[Scruffie]

Transistors did have dots painted on them... but if the colour of that dot relates to anything I don't know, it's a collector marker as far as I know.

If they were in a gain bracket they had a second dot painted on them in my experience, but I might be wrong.

It's probably a bit of mojo...

Thanks.  So there is something to it.  What then about all the images of NKT275s with no dots, as well the ones that pop up on ebay selling them with no dots?    Does the absence of a dot provide evidence it is a fake?

For example, here is an ebay seller with excellent feedback selling a lot of 10.  Could it be a fake?

http://www.ebay.com/itm/10-germanium-transistors-NKT275-Fuzz-/380399165339?pt=LH_DefaultDomain_0&hash=item58918e9f9b

Those aren't the original style, These are what most people are on about - http://diymusician.files.wordpress.com/2011/08/img_2285.jpg

Paint could be missing for a few reasons, either fakes, new production or it just came off cause they're probably almost 60 years old... or they didn't add it in the first place for some reason.

[Electric Warrior]

Scored a couple with no dots several years ago:



great sounding transistors. all very low leakage. in a fuzz face circuit they clean up amazingly well. I can get a similar fuzz sound with 2sb175s, but they don't clean up as bright and sparkly as the NKTs.

[R.G.]

At this distance in time, there is literally no way to tell.

NKT275s have been sought after for so long by so many people that it's a good bet that nearly all the little pockets of remaining real ones have been bought. It's worth noting that some companies make germanium transistors today. Germanium Power Devices is one such. Years ago, I called up GPD and discussed the NKT275 and other such devices with them. They said in effect "sure, I can make you NKT275s." I have no doubt that they really could make devices which meet all of the published specs of the NKT275 (or in fact, most other germanium devices) just fine. And so if it meets the specs of the NKT275, it can be called one.

If that's what you want. The things that matter to a fuzz face or other pedal which uses germanium devices to make distortion are things which do not appear on datasheets, and particularly did not appear on datasheets from fifty years ago.

So:
(1) is this here device a real NKT275?
Depends on what you mean by "real NKT275". As long as "NKT275" is not someone's trademark, it is if I say it is. Quoting one of my favorite spin specialists, William Jefferson Clinton, it all depends on what your definition if "is" is.
(2) is this here device an NKT275 made by [Newmarket, or insert company] back in the 60s?
Maybe. Prove it isn't. (speaking here for the seller)
(3) does it matter if it's a real NKT275?
No. What matters is how it acts in a circuit, not what's printed on the case. The lettering "NKT275" on a transistor don't say **anything** about how it sounds.

I think the best thing to do is to NOT buy germanium devices which are sold by name or type number. Buy based on individual device testing.

[fuzzy645]

Thanks RG.  All good points as usual. This seller speaks nothing of HFE and/or Leakage so it would be unlikely to be a good batch and the authenticity seems quite suspect too.

[Earthscum]

None of the vintage transistors (that I've noticed) seemed to show the skirt, like the NTE. I may have just not been very observant, but all the vintage ones and not "possible fakes" have caps tucked inside, like the ones on the left. (I love that RCA... I don't want to put it in a circuit, but it's gonna happen eventually, lol...)

[R.G.]

Thanks RG.  All good points as usual. This seller speaks nothing of HFE and/or Leakage so it would be unlikely to be a good batch and the authenticity seems quite suspect too.

The problem is that it's impossible to tell. And the seller may or may not know. Or what they do know they may have gleaned from what they were told on the internet.

[SteveG]

Also, absence of the 'skirt' in itself cannot be taken as an indication that the transistor is 'vintage'. At least some modern production AC128's lack the skirt.

It's just too easy to re-ink stamp transistors. Someone somewhere must be doing it!

In my experience, new transistors (carefully selected) are perfectly fit for purpose. There's just no point messing with old ones.

Steve

[Electric Warrior]

Some people ARE doing it. Gotta be careful with NKT275s nowadays. Always check for signs of restamping.

I've seen NKTs with and without the skirt, with different colored dots and a number of different fonts. They even changed the fonts twice while the germanium Fuzz Face was in production. Go figure.
The one I posted is probably 70's production. Some of the white dot NKT275s that Analog Man and Cornell used had the same cans:

[Earthscum]

Neat! I know NTE re-stamps their stuff... I usually find myself scratching off their IC numbers to get to the hot stamped ones underneath rather than trying to decode their partial datasheet copies. I think I noticed, actually, that the germaniums I've seen were usually skirted. I don't have any, except NTE's that have skirts (actually, most of mine are the old oval cans and tophats, lol... and a couple CK722's).

[PRR]

> some companies make germanium transistors today. Germanium Power Devices is one such. Years ago, I called up GPD

I'm pretty sure GPD dropped the ol-skool Ge products when they moved to New Hampshire.

http://www.gpd-ir.com/about.htm

If there's a Ge foundry still hot, it might be in China (they got the coal). Perhaps not, because I bet the Russians made and stockpiled so many that even the Chinese don't want to bother.

[R.G.]

It was a long time ago that I talked to GPD. Even then, they only cooked parts to order. Minimum was about $10K as I remember.

[Electric Warrior]

Magnatec/Semelab makes or made some until recently. There's also American Microsemiconductor and DSI.

[zombiwoof]

Transistors did have dots painted on them... but if the colour of that dot relates to anything I don't know, it's a collector marker as far as I know.

If they were in a gain bracket they had a second dot painted on them in my experience, but I might be wrong.

It's probably a bit of mojo...

Thanks.  So there is something to it.  What then about all the images of NKT275s with no dots, as well the ones that pop up on ebay selling them with no dots?    Does the absence of a dot provide evidence it is a fake?

For example, here is an ebay seller with excellent feedback selling a lot of 10.  Could it be a fake?

http://www.ebay.com/itm/10-germanium-transistors-NKT275-Fuzz-/380399165339?pt=LH_DefaultDomain_0&hash=item58918e9f9b

These appear from the pics to be the small/skinny-can version, as others have noted the larger package type are the vintage type that are the in-demand ones used in vintage pedals.  There are a lot of these small-can ones around, and many fakes as also noted (Dunlop uses similar trannies that are probably re-stamped germanium devices in their regular red Fuzz Faces).  It's the same story with AC128's, the larger-package type are the ones that are desirable, although you can get a reasonably-sounding Fuzz with the smaller package ones, and again there are re-stamped fakes of other designations that have similar specs.

In the case of that seller, I bought some 2SB-176's and AC128K's from him and am using them in my modded Dunlop FF, he ships pretty quickly and does have a good reputation, just know what exactly you are buying before purchasing.

Al