Skinny NKT275

[jimmyandrex]

I'm after some NKT275 for various fuzz projects. I read somewhere on the AM sunface site that the skinny nkt275 are to be avoided as they don't "sound" right - are these the type referred to? which I have seen advertised

http://i783.photobucket.com/albums/yy113/sausage1953/nkt275_zps0074ffac.jpg

They look a bit different to the picture on the sunface site

http://i783.photobucket.com/albums/yy113/sausage1953/fakenktsunface_zps0725f38d.jpg

I'm unable to find red dots etc so will this type do assuming they are ok for gain?leakage etc and are not fake - or should I avoid

[zombiwoof]

The original NKT275's are the large-can (TO-1?) size.  The skinny ones with the tab are modern production, and not really the same.  I did get some skinny-can types from Ebay that are actual vintage Newmarket-made transistors, they don't have the emitter-indicator tab on them, they are supposedly just a later version of the original TO-1  Newmarket NKT275's.  Haven't tried them in anything yet, but I'm planning on trying them in my modded red Dunlop Fuzz Face.  I think the ones to avoid are the ones with the indicator tab on the case, these might even be relabeled transistors of another type (I know that the skinny ones in Dunlop Fuzz Faces are this).  Same thing with AC128's, the skinny ones with the tab (usually made by Tungsram) are more modern production, the vintage type are the larger TO-1 can.

Al

[jimmyandrex]

The ones advertised in photo do appear to have a tab so maybe I should avoid these

[IvIark]

I got a few of those NKT275s and the couple I've used were very nice in a Fuzz Face, just don't pay NOS prices.  Luckily they were also pretty much exactly the recommended gain 82 and 122 hfe which was a bonus.

I've used horrible sounding NOS Newmarket transistors and so that can be a crap shoot anyway, so I've pretty much given up on believing any transistors are the Holy Grail.

[smallbearelec]

Hi--

If you insist on having the magic part number, you will almost surely get re-labeled devices that may or may not sound decent. Gain and leakage are likely to be all over the map. Depending on how reputable your seller is, you might or might not be able to get your money back if you are not happy. These are realities of the old-stock germanium transistor market that I have coped with for almost fifteen years now. It's opaque and treacherous, to the point that it makes a bazaar in Kabul look transparent. The market has gotten steadily more difficult since I entered, as the interest in cloning vintage gear has grown and the supply of devices of known provenance has diminished.

I have long gotten a lot of requests for quantities of "Fuzz Face-quality" germanium, and I turned them down until recent years. Over time, I realized that I had accumulated a list of suppliers, many not well-known to the public, that have substantial lots of decent-quality parts. Some are branded, some are unmarked and/or "house-numbered". You'll find those here:

http://www.smallbearelec.com/servlet/Categories?category=Germanium+Transistors%3ABulk+%22Rough-Sorted%22+Lots

They are mostly fairly expensive, and there are no quantity breaks. But I do sample them when I get them in, and I guarantee that they will be what the description says they are with respect to gain and leakage. I can't guarantee tone, because it's so subjective. But you can buy small quantities with my assurance that I know what the parts are and where they came from.

Regards
SD

[Electric Warrior]

Same thing with AC128's, the skinny ones with the tab (usually made by Tungsram) are more modern production, the vintage type are the larger TO-1 can.

But there are recent production TO-1 transistors, too. Magnatec made AC128s in a TO-1 can until recently. I heard they were pretty good.

[Magnus]

Hello,
as a friend of fuzz-sounds I thought I have to post what I personally think about it...

I have built two Fuzz Face's:
- one with NOS AC128 from Tungsram, the small-enclosured transistor-type which is often used for Fuzz Face-Clones
- and one with NOS AC128 from Philips/Valvo(?) in the bigger TO-1-enclosure

Facts:
- both transistor-pairs are matched for a good hFe and a low Leakage
- both pairs/pedals sound very nice
- there are differences in sound, mostly in highs and midrange, but I could not really say what I prefer - I like both
- its nice to have some transistors which are rare but I won't pay hundred or more Dollars for a pair of matched NKT275 - never!

Here is a small article about the AC128 germanium-transistor:
http://www.jacquesstompboxes.com/ac128.htm

Pictures of (some of) my transistors:
NOS AC128, Philips/Valvo(?), TO1:
http://forum.musikding.de/cpg/albums/userpics/17258/AC128_%282%29.jpg
http://forum.musikding.de/cpg/albums/userpics/17258/AC128%2C_matched.jpg

AC128, DSI, current production (going to build a fuzz with some switchable transistor-pairs including this pair):
http://forum.musikding.de/cpg/albums/userpics/17258/NKT275_DSI.jpg

Important things are hFe and low leakage, Germanium PNP,
you can try AC125, AC128, other AC- and OC-types, other (cheaper) NKT-types or whatever you can get.
What matters is matching them and to listen what you personally like

http://www.geofex.com/Article_Folders/ffselect.htm

I tried some more transistors in a fuzz face perfboard-prototype,
every single ge-transistor sounds different - even same types with close measured values in hFe and Leakage!

There are NKT275-fakes around - be carefull...


Greetings from Germany
Magnus

[zombiwoof]

Same thing with AC128's, the skinny ones with the tab (usually made by Tungsram) are more modern production, the vintage type are the larger TO-1 can.

But there are recent production TO-1 transistors, too. Magnatec made AC128s in a TO-1 can until recently. I heard they were pretty good.

Yes, there are those recent Magnetec TO-1 case AC128's around, and also I think they (or another company) made OC81D's.  I've also seen some recent TO-1 case NKT275's somewhere.  The problem with them was, according to Steve at Small Bear, all of the batch he ordered were very low gain (in the 30's for hfe).  When he asked them if they could supply him with higher gain versions, which would be more suitable for Fuzz Faces and the like, they wanted to charge him a gigantic fee for pre-selecting values.  So if you order any of those, don't be surprised if they are very low gain devices.  People have reported similar problems with the OC81D's.

Those NKT275's in the skinny case with no tab on them that are being sold on Ebay are genuine New Market made transistors, the seller showed a pic of the bag they came in, with the batch and manufacturer information on it, unless he went to the trouble of faking the bag they came in, they are not relabeled transistors.  They are also pre-tested and marked for gain.  I will be trying them out soon in my FF.

Al