Re: More Uniwatt Transistor subs

Great information. The only downfall I can see is that they are TO-220 case
style. While this is just fine for the WG and Electrhome boards, the amplifone
could be a bit more tricky to mount.

Just my $.02

tom mcclintock wrote:

> Here is some info I got from Rodger Boots regarding transistors subs. I
> was originally looking for some good G05 transistor substitutes, but I
> suppose these would work well in other situations. :)
>
> ---------------
>
> Uniwatt transistor availability and cost getting you down?
> Looking for better parts at lower cost??
> Not scared off by the fact that pinout and heatsink mounting will be
> different???
>
> WELL I HAVE A DEAL FOR YOU!
>
> But, seriously, here's what I did. I went to DigiKey, used their
> transistor selection capabilities, sorted the results by PRICE, and
> tried to find inexpensive replacements.
>
> First, the NPN transistor:
>
> MPS-U01, MPS-U05, MPS-U06, & MPS-U07 can all be replaced with a
> 2SD1264
> at a cost of $.89 each, DigiKey part number is 2SD1264A-ND. Buy 10 for
> $7.42 or 100 for $59.33. (Too expensive? All except the MPS-U06 &
> MPS-U07 could be replaced with the 2SD2374 at $.77 each/ 10 for $6.45/
> 100 for $51.59).
>
> But, you say, what about PNP transistors?
>
> MPS-U51, MPS-U55, MPS-U56, & MPS-U57 can all be replaced with a
> 2SB940
> at a cost of $.97 each, DigiKey part number is 2SB940A-ND. Buy 10 for
> $8.06 or 100 for $64.49. (Too expensive? All except the MPS-U56 &
> MPS-U57 could be replaced with the 2SB1548 at $.85 each/ 10 for $7.09/
> 100 for $56.75).
>
> Of course, as always, I could be completely full of it, but they look
> like they should work. And, of course, I have no way to test this
> myself. They handle over twice the power and way more current, but the
> pinout is different (so careful lead bending will have to happen to
> install them) and the old heatsinks might not fit. If the old heatsink
> have a mounting hole they should be able to be screwed to the new parts.
>
> Part of what I was trying to do was to keep it under $1 per part. As
> good a criteria as any. Somewhere I have several hundred TO-220 heat
> sinks, maybe a package deal could be made? (Uniwatt transistor used a
> modified TO-202 case with a thin extended tab that sticks out of the
> case. The transistor style of choice these days is the TO-220 which has
> a thick metal tab that is the entire back of the case. This allows the
> transistor to handle way more power and run cooler than the TO-202).
>
> ---------------------------
>
> tm
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Received on Wed Jul 24 16:46:20 2002