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  • Germanium NPN - New Jersey Semiconductor

    I've recently built a number of Fuzz Faces in numerous iterations. I'm enjoying the experimentation. One in particular that works well uses a 2SD43 Toshiba germanium NPN transistor for Q2. I salvaged this from an old AKAI reel to reel that bit the dust. I found some of these available for sale. The manufacturer is listed as New Jersey Semiconductor. I don't know the cost yet as I have to request a quote. Before I do that I'd like to know if anyone knows anything about NJS. Their site says they offer JEDEC and original Japanese types. I'm not sure what that means. Can anyone shed some light on this for me?

  • #2
    There are some companies that specialize in making new versions of older devices. In some cases they have bought the fab equipment to make the old stuff from scratch when a bigger semiconductor company updated their wafer fab lines. I know this is true of Germanium Power Devices"; perhaps New Jersey Semiconductor does this as well.

    If that is the case, these are newly manufactured devices which meet the specification for the older devices. Let's look at that for a minute.

    What is a 2N3904? It is any chunk of silicon that meets the specifications for min/max values on a datasheet marked "2N3904". The "2N3904" is a registered type, meaning that anyone who makes these will have to meet at least the registered specs. Notice that reading datasheets is a fine art. Some parameters are specified only as minimums, some as only maximums, and some as only "typical". "Typical" in particular means **nothing** unless you want to get into statistical margins and lawsuits.

    But it is entirely possible that the same semiconductor die would meet the specifications for ten, or ten thousand datasheet types. And this is what the replacement semiconductor places like NTE have made their business on. It works the same way for a semiconductor remanufacturer today. We have much finer control of semiconductors today than back when germanium devices were made by sticking a chunk of indium on each side of a chip of germanium and baking it for several hours. So a company can find a reasonable target for its processes that result in a chip that meets the published specs for many devices. They don't have to make a zillion different types.

    And so if you get a "2SD43" from NJS, or Germanium Power Devices, or whomever, is it a "2SD43" or not?

    Yes, absolutely: it will (probably) meet all of the parameter limits on the 2SD43 datasheet. Will it sound just like the 2SD43s you pulled out of that Akai? Who know? Maybe. Could happen. But how it sounds is NOT a datasheet parameter. In the effects world, we mostly use stuff not as it was intended to be used, but for the edge effects and unintended consequences. No manufacturer specs those; they don't even look, and would refuse to look if you asked them to.

    It is dead certain that the NJS devices are not the same as the ones Toshiba made forty years ago. It is unlikely that Toshiba could make exactly those, as they can't do things that sloppily and poorly today. But there is no way to tell if the new ones will be better, worse, or the same in a Fuzz Face. None at all.

    This line of reasoning is why I keep telling people to ignore the part number on the device; test it for what is known to make good fuzz faces (or whatever) and be happy with what you get.
    Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!

    Oh, wait! That sounds familiar, somehow.

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    • #3
      JEDEC means "American" types, like 2N109 or 1N4007. JEDEC is Joint Electron Devices Engineering Council.

      Japanese types are of course the 2S series of numbers like 2SA1815 or 2SC945.

      I don't know the company, but I suspect the JEDEC and Japanese reference is just to let you know they offer both.

      And again, I don;t know them, but in my experience, most places that have "request for quote" are not looking to sell 5 or 10 of something.
      Education is what you're left with after you have forgotten what you have learned.

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      • #4
        Thanks RG. I'd read about the NTE process (possible something you wrote) and was wondering if this was similar after market manufacturer. I've also found what you said about spec sheets to be true as I've been reading many of them lately. What was really fascinating is the min/max range in the hfe column on some devices. Based on that spec alone one could get a large batch of a device that would fall into the "range" but be worthless for an application, such as a fuzz face type circuit.

        The batch I found are from a semiconductor broker and they list NJS as the manufacturer. This broker happens to be my counsin. They've been in the business for a long time. She lives in another part of the country but I've kept in touch with her over the years mostly about family, but have never purchased anything from them because I've never had a need. My thinking is, the 2SD43 probably isn't a real high demand item, as I've never seen it referenced in regard to a Fuzz Face application. I just happened to have one and it works very well. If I can get a batch of them at a reasonable price, I'm hoping I can find enough that fall into a useful gain range, low leakage, etc to make it worth my while. And maybe she'll throw me a bone and not require that I purchase a huge lot. That's a big if because there's family and there's business.

        On an interesting side note, my next door neighbor until recently was a semiconductor broker. He got out of it and went to work for someone now. He told me the semiconductor broker business is really taking a hit because of RoHS requirements.
        Most of the old semiconductors are not RoHS compliant and the demand for the stuff he was working with was dwindling. One of those unintended consequences of a good intention.

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        • #5
          Thanks for the reply Enzo. As mentioned in my reply to RG, I'm hoping my loose family connection can get me an in without having to make a huge investment.

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          • #6
            Originally posted by casey73 View Post
            This broker happens to be my counsin. They've been in the business for a long time. She lives in another part of the country but I've kept in touch with her over the years mostly about family, but have never purchased anything from them because I've never had a need.
            Wow! A cousin in the business! That's a great intro. The problem I've always had with semiconductor brokers is that it's nearly impossible to get information about what you get. If you get no extras from the family connection than more info, that's huge.

            My thinking is, the 2SD43 probably isn't a real high demand item, as I've never seen it referenced in regard to a Fuzz Face application. I just happened to have one and it works very well. If I can get a batch of them at a reasonable price, I'm hoping I can find enough that fall into a useful gain range, low leakage, etc to make it worth my while. And maybe she'll throw me a bone and not require that I purchase a huge lot. That's a big if because there's family and there's business.
            Good idea, and from my quick look at what data is available, the 2SD43 will be a good candidate. At the right price, it's a good go. You should probably guess that you will get only 1/3 of the number you buy that will work well in a Fuzz Face, based on my experience with AC128's. but at the right price, buying three times as many as you need is reasonable, especially if they are cheap to start with.

            One of those unintended consequences of a good intention.
            That is almost a fundamental concept of government. Any time they get into proactive do-gooding instead of doing only what is screamingly, shriekingly necessary, the results are almost purely unintended consequences. And may all the deities save us from governmental actions intended to "send a message". Governments should exist solely to do things that people can't do for themselves, like preventing abusive exploitation (theft, fraud, embezzling, etc.) and building things everyone needs like roads and national armies. A government is simply not subtle or insightful enough to do subtle things right or well. And forcing people to do things for their own good is not in that list of things.

            The issues of forcing energy efficiency by fiat fall into that. The idea of outlawing incandescent light bulbs, which is spreading around the world, or outlawing non-switching wall warts falls right into this. If the energy saved is worth it, people will do it for their own pocketbooks. However, the temptation for governments to do things just because they enforce greater control of the subdued...er, peasant... er, governed class is almost irresistible. As Abraham Lincoln observed, adversity is not a good test of character; almost anyone can resist adversity. If you want to test a man's character, give him power.
            Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!

            Oh, wait! That sounds familiar, somehow.

            Comment


            • #7
              That is almost a fundamental concept of government. Any time they get into proactive do-gooding instead of doing only what is screamingly, shriekingly necessary, the results are almost purely unintended consequences
              You are preaching to the choir here RG. Twenty years working as admin and tech support in public education gave me a real good look at the world of good intentions gone awry in an environment largely removed from the real world. My wife still works in that environment and it is interesting to see how quickly the real world intervenes now that money is getting real tight. Pull the plug on the free flow of cash and your typical academic becomes dazed and confused when they start getting no for an answer.

              Back to the matter at hand, I've sent off my request for quote to my cousin broker with a personal note and am awaiting her reply. Will let you know how it works out.

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              • #8
                You might consider measuring the basic characteristics (hfe, leakage etc.) of the one you have in hand. The specs on an old part like that could very well have drifted considerably through age and use.

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                • #9
                  Here's an update. My cousin the broker told me in this case it would be more cost effective for me to go direct to the supplier, in this case NJS and another manufacturer in New Jersey she suggested. I sent NJS an RFQ and they never bothered to reply, so I decided to skip them. Even a short reply would have been nice. I contacted the other company by phone. I was sent to the guy who said he managed the place. I told him I was looking for the 2SD43, which their site said they had over 4000 in stock. He said "that would be our NTE101" and said he could sell them to me for $10 each, min order $50 plus UPS shipping. I asked if they were made on site and he said "we have 200 in stock". Kinda like politicians who never really answer the question but give an answer for something you didn't ask. I thanked him for his time. My interpretation of what he said is, he looked at on old cross reference and saw that 2SD43 crossed to NTE101, and they had NTE101 in stock from another source. They may have made germanium stuff at some point, and maybe still do for specialty applications, but clearly they are just reselling the NTE101.

                  I knew the NTE101 has appeared as being used in fuzz face type circuits, and they are available for $8.00 if you look around. I went down to the local Frys Electronics and picked up 3 of them for about $8.50 each after taxes. I did a quick gain test and got 1 at 30, 1 at 129 and 1 at around 300 hfe. Haven't checked them for leakage yet.

                  The moral of the story, which I'm sure most people reading this already know is, for what I paid for my NTE101s (which may or may not be useful) I could have got some tested and gain sorted germanium transistors from Small Bear. For the small scale I build on that is the my best option. Every now and then a guy can stumble onto a lucky find of NOS stuff like useful germaniums but more often than not it takes alot of time beating the bushes to find them and then being able to purchase in bulk to make it cost effective. So it cost me $26 to be reminded of that and I've spent more on a bad meal. I don't know for sure, but my guess is Small Bear probably does not make much on the germanium transistors he sells, and does it more as a service to draw in purchases for other things. In the mean time, I'm sitting on my one good 2SD43 waiting for it's stock to go up.
                  Last edited by casey73; 01-08-2011, 09:20 PM.

                  Comment


                  • #10
                    I guess 99.9999% of those who offer germanium transistors today do not make them at all; economics make that impossible, *but* there are still millions of them collecting dust in damp basements, most of them unaccounted for by those who have them.
                    I guess some of those people find the dusty cases, don't want to throw them in the garbage, can't sell them either in a normal way, as the market is practically inexistent (an Industry can't live out of a few Fuzz Face makers), and so simply let the fact be known to some ressellers/suppliers (such as your cousin), who post them in their pages, where search robots find them.
                    *If* somebody (such as you) needs a couple or a thousand, you ask the people you found who in turn ask backwards and so on until the actual devices are found.
                    Very iffy, involved, unefficient, etc.
                    I agree you should forget about specific part numbers and simply try to get any "germanium small signal transistors" and use them.
                    The original Fuzz Face makers didn't use them because they had "good sound" but because they were state of the art way back then, cheap and plentiful.
                    I remember when I started in the late 60's that I could buy anywhere the Toshiba or Hitachi "transistor kit", a small bag with 6 metallic case germanium 2SA and 2SB transistors, necessary to build the classic 6 transistor AM radio.
                    3 were RF types; 3 audio ones.
                    I'm sure there must be millions of transistors such as those stashed and forgotten, but it does not pay for the unknown (to us) owners to even try to sell them.
                    I think it may pay to rummage in old attics, or Salvation Army type places for very old AM radios.
                    Juan Manuel Fahey

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