103nu71?

ckyvick · Post by **ckyvick** » 19 Jun 2010, 21:40

Are these any good? If not, which transistors lots should i look for on ebay to use in npn fuzzes?
https://cgi.ebay.com/Germanium-Transist ... 51841ac94d

RnFR · Post by **RnFR** » 20 Jun 2010, 03:23

i've got some at home. i think they are a good deal for the price you pay. usually around 75 Hfe i believe. not the best in the leakage dpt, but they'll get by.

makepeace · Post by **makepeace** » 15 Dec 2011, 07:17

I know this is an old post, but I believe the contrary in the leakage dpt?

In the latest lots that are available, they have a tested Hfe of between 50 and 80 at an Ic of 1mA and Vce of 3V and leakage of between 1 and 5 uA, with Vcb of 8V. Surely the leakage is more than low enough for application in any fuzz/boost box? I've read that the leakage must be below 150uA.

RnFR · Post by **RnFR** » 15 Dec 2011, 07:45

sounds like you got a much better batch than I did. but like I said, they work fine, and I have used them in many fuzzes in the past.

KindaFuzzy · Post by **KindaFuzzy** » 15 Dec 2011, 12:28

Mine are super low leakage, but low hfe around 30-50. Sound great in rangemasters.

makepeace · Post by **makepeace** » 05 Jan 2012, 16:05

Man KindaFuzzy, thats exactly what I wanted to hear.. I bought a lot a couple of weeks back - to build some rangemasters!

hfe of 30-50 is a bit low than the stock value for rangemasters is it not? are you able to get the 'right' tone by appropriating the bias?

KindaFuzzy · Post by **KindaFuzzy** » 05 Jan 2012, 20:11

I used one that was around 40 and it worked great after tweaking the resistors like rg keen describes in the Austin treble blaster.

makepeace · Post by **makepeace** » 17 Jan 2012, 12:01

just soldered one of these into my rangemaster and tweaked the collector voltage to about 6.9V, Rb is 27K, which is quite low compared to the 100K stock value. my power supply is putting out 8.6V only, so that's possibly the reason. doesn't sound nearly as full as my OC71 did though :/.

does anyone have any ideas for a circuit i can build to test the gain ballpark of these transistors? put them into my hFE tester on my DMM, and most of them are around 90-110, but thats probably overstated because of leakage. i've tried RG's fuzz face germanium test circuit, and followed the instructions for testing NPN's, but i keep on getting strange values.

also, does anyone have any suggestions for fuzz circuits i should be trying out with these lower gain germaniums? tone bender?

makepeace · Post by **makepeace** » 17 Jan 2012, 21:04

Also, does anybody know which way round the collector and emitter leads are? The one I soldered in was by chance the right way round. I'm guessing if you're looking at the printed label, the lead right of center is the collector. Anybody know for sure?

ckyvick · Post by **ckyvick** » 17 Jan 2012, 21:37

You might wnat to stock up on these:

makepeace · Post by **makepeace** » 18 Jan 2012, 15:22

ckyvick wrote:You might wnat to stock up on these:

got lots of these:

anyone have any ideas as answers to above? please

KindaFuzzy · Post by **KindaFuzzy** » 18 Jan 2012, 23:49

Very bottom of the page, number 1 pinout. http://nf.duseknet.com/tranzistor.htm#1

Rangemaster setup instructions: http://www.geofex.com/article_folders/r ... tboost.pdf

How to test germanium transistors: http://www.geofex.com/Article_Folders/ffselect.htm

frequencycentral · Post by **frequencycentral** » 19 Jan 2012, 00:28

Great thread!

makepeace · Post by **makepeace** » 20 Jan 2012, 12:33

Thanks kindafuzzy.

ok so i've been testing though a lot of these. the ebay seller said that they have leakage of between 1 and 5 uA at 8V, however as tested, 25 out of 25 have leakage over 200uA at 8.29V :/. some have leakage up to 800uA. about 3/25 have leakage around and below 300uA. gains in this batch measured between 50 and 110 or so. i have a pair here that are suitable and will be going into an NPN fuzz face a bit later. hopefully the sounds are good.