Vintage Transistors

[antiquekid3]

Does anyone really use old transistors for projects? I have a bunch of TO-39 package transistors as well as a few germanium power transistors. I'd love to build a nice headphone amp with a few of these. (the smaller, the better!) I have a pair of Sennheiser HD-555s that I will be driving. They are 50Ω headphones.

I've tried to use TINA-TI to get an idea of what kind of circuits will work and which ones won't. I've had a few successes, but TINA doesn't have the transistors in its library that I have.

Any suggestions?

Kyle

[Enzo]

Well, often as not, circuits are circuits. Something built with say TO220 outputs might be converted to TO39 outputs with appropriate reduction of ratings. Worth experimenting.

[Captain archer]

If you give the part numbers of all the parts i will see if i can design a headphone amp for you that is simple to build and stable and also within limits of the specs from those old transistors.

Greets captain out...............!!!!

[Mooly]

Have a look at this one of mine,
http://www.diyaudio.com/forums/headp...phone-amp.html

[antiquekid3]

Alright Captain, here's a list of what I have. First off, the TO39 style:
2N1304 x4
GEC6B x5
ECG123 x4
T53658 x11
2N1671A x2
2N1671B x2
2N1302 x6
2N1415 x10
2N404 x3
2N4036 x4

And now the random ones:
2N4276 x9
MJE521 x8
2N3646 x21
2N5376 x9
2N914 x14
2N5190 x3
2N2646 x4
HEP50 x2
MJE371 x6
D40C4 x8

And Mooly, that's a super professional job on that headphone amp! I'm very impressed! I wish I had those kind of transistors laying around as I'd definitely be inclined to building one. The idea of having a rechargeable headphone amp (with a really neat low battery indicator!) is awesome. Nice work!

Kyle

[Mooly]

Thanks
That's quite a list you have there... and tbh I don't recognise any by the numbers, but I'm sure (says he without recognising any) that they must be suitable for a similar kind of design as the one I came up with.

I'll have a look at some of the data sheets for them later...

[Mooly]

Had a quick look in an old Towers book,

The 2n1304 is NPN and the 2N1415 is PNP rated @ 500ma and 0.25watts in free space. I'm sure they would work straight off in a design like mine, it's very non critical. The 2N404 is PNP and 100ma max.

The MJE's and the 2N5376, 5190? and 2N914 are Silicon.

The 2N4276 is a real special... 60 amps rating at 170watts, but a low voltage rating around 25volts.

[indianajo]

"Does anyone really use old transistors for projects?" I used some 2N2905 salvaged from a TI DFS2 in 1973 to build a phase shift oscillator recently. The circuit was in the GE Transistor Manual seventh edition. I needed a stable sort of sine wave source to balance out the channels with an oscilloscope of my ST120 power amp and PAS2 preamp. (The ST120 was okay with old unmatched transistors everywhere,the unbalance was in the PAS2 preamp which needs new capacitors to replace the 1960 vintage paper ones, I decided). The textbook circuit had NPN, but I converted it to PNP since I had these in a box. Not everything is a power amp, where the new output stage transistors are clearly superior. Actually the ST120 power supply foldback circuit was too aggresive with a modern transistor installed, I found a real rusty 1970 vintage RCA transistor with low enough gain to give me 6.5 amp protection per spec instead of 2 amps with the newer NTE60 transistor.

[antiquekid3]

Okay, I found some old Japanese transistors that should work a lot better for the amp. I was wondering if you might be able to send me your DipTrace project file so I can make a circuit board too. Also, do you have a complete parts list for your amplifier?

Here's the list of transistors I found:
2SB22 x2
D352 x12
2SB405 x6
B324 x7
Sony C76 (also has EP81 on the case) x9
2SA341 x5
SK-3004 x1
SK-3005 x1
SK-3006 x1
2N375 x2 (TO-3 germanium)
2N109 x2
WEP201 x1

I'm thinking the first few Japanese transistors will make good transistors for the amplifier. I might try the 2N375s in a Class A power amplifier...is this a common arrangement for power germanium PNP transistors?

Kyle

[Mooly]

Originally Posted by antiquekid3

Okay, I found some old Japanese transistors that should work a lot better for the amp. I was wondering if you might be able to send me your DipTrace project file so I can make a circuit board too. Also, do you have a complete parts list for your amplifier?

Send me a PM with an email address and I'll send the Diptrace file.

No parts list as such... you'll have to go through the circuit diagram, but it's all common stuff.

The Diptrace PCB view (you can mirror it anyway from Diptrace) is looking down on to the components, as this is the view I print to Jetstar transparancy to use directly in UV light box.

Originally Posted by antiquekid3

I'm thinking the first few Japanese transistors will make good transistors for the amplifier. I might try the 2N375s in a Class A power amplifier...is this a common arrangement for power germanium PNP transistors?
Kyle

2N375, another one I would have to look up. Class A (in a power amp) and germanium doesn't really sound a happy combination... you would have to keep temperatures right down and have a firm grip on the bias arrangement or the thing really would go into thermal runaway. Interesting idea though