Low noise NPN with ECB(123) pinout

percy

Member
2004-04-25 5:47 pm
CA
I am looking for a substitute of 2SC2240 (which was actually a substitute for 2SC458). Both transistors are no longer in production so I want to try something current.
Application is Low Noise (tape/mic preamp) so would like to get something with good noise performance. Would prefer plug-in substitute hence the pin config mention as well.
The board layout is such that the lead holes are in a straight line (unlike sometimes in a triangular position) so would prefer a pin config where I dont have to bend and twist the leads too much.

Thanks!
 
2sc1815 should still be available, and similar to 2SC2240 in term of noise. With leg twisting and heat shrink tubing you could also use BC337 (EBC) pinout, again similar in noise.

The 2SC1815 and 2SC2240 are still available from ampslab.com (though you need to buy 50 pcs at the same time). You can buy low quantities of 2SC1815 from amb.org.
 
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I hope somebody can suggest a suitable device. Every month it's more difficult to find thru-hole transistors in general - and that ECB pinout was always much less common than EBC or CBE. (Going from memory I'm inclined to say that ECB usually indicated a device with either higher power rating, or higher voltage rating, than typical TO-92 applications, such as a driver device, rather than a low-noise small signal transistor.)

Since the lead holes are in a straight line I would suggest mounting a lo-noise SOT23 transistor like 2SC3324/2SA1312 on an itty bitty PWB (or vectorboard) and make connections with short lengths of stiff hookup wire, or some pins clipped off a header connector. You can get pre-made adapters like this from the usual online sources.

Dale