Phillips/Telefunken did, but I can't buy those here. campsquire just refurbished a 35 year old Peavey CS800 Making a Vintage class A/B LighterĪnd he didn't use any transistors, mainly replaced transistor sockets ecaps thyristor and fan.įairchild BC139/140 don't come with an Ft spec. If your amp is original and ailing, concentrate on electrolytic caps, dirty pots and oxidized connectors, geriatric mica washers, is my advice. I've got some NTE181 which have same soa specs as MJ15003 (which they probably are) and they are 38 years old, used 2000 hours a year some years. MJ15003/4 are fine output transistors but MJ21193/4 have more SOA & are cheaper. However my units were from Phillipines fab has moved to ***** now that On bought Fairchild. I found very low noise with MPS8099/8599, but not specified. What is that, a VAS? If pinout matches use MJE15028/29 as above.īC556 from Telefunken or Phillips have great noise specs, but if you check the fairchild datasheet of what you can actually buy fairchild left that out. KSD1616 is not available to me, not looking it up. I was getting gain of about 300 out of a MPS8099, gain is not expensive these days. Not available, use 2N5400 or 2n5401 which are more expensive.
#2n3906 transistor substitute for 2n1307 drivers
Dynaco used heatsinks on the drivers and I did too, also VAS.Ģn3906 is a bit light on Vceo for ruggedness. I found better sound with MJE15028/29 as drivers and as VAS too. TIP31c/32c have too low a Ft to reproduce 10k-20k hz without IM distortion.
In fact the surviving TO5 drivers sound better on top octave piano & tinkly bells than NTE49/50 and TIP31c32c I tried as replacements.
I've got 50 year old transistors except the outputs on one channel of my dynakit ST120 and they work fine. If you are scratch building, fine, but I don't see why the front end transistors need replaced on an existing unit.
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