![]() Safe Operating Guidelines / Absolute Maximum Ratings The procedure of using these transistors is same as we use any other PNP transistor. The NKT275 transistors are mostly used in fuzz face devices but they can also be used to replace other similar transistors. As mentioned above that the NKT275 and AC128 are not manufactured anymore but they can still be found with some electronic sellers which stock up old components. The fuzz face circuit is easy to build and required only few components but its main components are the PNP germanium transistors, however, these days you will also find fuzz face devices that uses silicon transistors but people still like the of ones that use germanium transistors most likely AC128 and NKT275. The fuzz face is an analog device connected with the guitar and provides different tones or effects in guitar sound. As the technology of transistors progresses, newer silicon transistors are being replaced by these older transistors which are more accurate, reliable and good performers as compare to these older germanium transistors and hence the companies that were making these transistors gradually discontinued their manufacturing.īut some of these transistors are still well known by some fuzz face makers and users. In that time it was a common transistor like AC128. NKT275 is an old germanium transistor that was available around 1960’s. NKT275 Transistor Explained / Description Max Storage & Operating temperature: 90 Centigrade.Minimum & Maximum DC Current Gain (h FE): 70 – 130.Max Collector Dissipation (Pc): 200 Milliwatt.Max Collector-Emitter Voltage (V CE): 15V.It will vary.Advertisements Features / Technical Specifications The 2N404s I sourced were especially consistent. Tl dr version: it's a pain, so buy a set if you're not prepared to invest more time and money than you think you'll need to invest.Īs far as devices go, I've had good luck with 2N404s and AC170s. And now I have a healthy supply of tested devices for future builds. I like cork sniffing, it turns out, even in a situation like this where the result is that I find out I don't think it ends up making a difference. Are you one of those people? If so: buy a set!Īll that said, I don't regret sourcing and testing my own supply. What I'm saying is, the testing is itself tempermental and seems to drive some people crazy. You'll have the device in the sockets and just the lightest touch will send the readings all over creation. It also gives you a good sense of just how temperature dependant germaniums are. Another headache buying a set avoids.ģ) Then you have to actually measure all the devices. This is easy to get from Mouser, but it takes time to get. But if you're going to build it you have to buy a specialized resistor (I think it's 2.49K 1% but don't hold me to that) to make the math work out. Lots of great info on Ge devices (thank you Mr. It's on GEOFEX and is worth looking at in any case. Keen has a simple circuit for testing Ge transistors. ![]() ![]() Understanding this in advance is important.Ģ) R.G. You might luck out and get a lot that are mostly keepers. You might get entire lots that are basically junk. The thing you have to accept is that you are, in fact, buying raw stock! This means you're paying for 10 or 20 or 50 transistors at a time, and at the end of the day only 20-30% are going to be useable. If you're going to do it for the love, then some comments regarding those three considerations:ġ) Sourcing: If you look on eBay, for instance, there are sellers who sell raw stock. So if you're not in it for the love, it's almost certaintly not worth it. It's not difficult, but it is time consuming. It means you have to:ģ) Use the test circuit to sort your raw stock so you can use it intelligently This is more involved than you might like or immediately recognize. If you're going to do multiple builds, then it can make sense to source and sort your own supply. Sure, they're expensive, but you know you're getting the good stuff and you don't have to expend all kinds of time and effort sorting things yourself. If you're just doing one FF and have no future plans to make other fuzzes, then I'd say bite the bullet and just pay Small Bear or another reputable seller for a set you like the look of. With regard to cost, I guess it depends on how you're looking at things. ![]()
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