[Lowfer] Clean bench

[Jay Rusgrove]

Mitch

Your signal has been present most of the morning after about 9:30 am with just
about enough to ID most of the time. Snowing heavy here now but noise is not too
bad.

Jay

Mitch Powell wrote:

> > In spite of the success and neatness of that amp I'm going to have to give
> > you a failing grade on the overall construction. You have TO-5 transistors
> > and heat sinks to boot. Shame! <G> This design calls for TO-92 plastic
> > devices and no heat sinks. To test efficiency you place your tung on the
> > transistors .... and I am 100% serious! (Ask Mike S)
>
> I know - but I was chicken - and usually overbuild these things. It's now
> very obvious that the heat sinks can be tossed. Can't detect any warmth.
>
> The transistors though - are re-cycled. I de-solder from computer/control
> printed circuit boards. It's kind of difficult to get a 4060 chip off when
> it's soldered on both layers, but it can be done.
> Those transistors are - 2N2218A and 2N2904A - which came from a board with
> half a dozen of each - so it looked like the price was right !
> Lower hfe than the 2222/2907 set - ( B = 90 instead of 200 )
> but ft is 150 Mhz - so they work.
> I am re-doing the board, now that all the mods are complete - and will
> send out to the deep-freeze next week.
> The picture shows the amp/DDS synthesizer exactly as they are working on the
> air. Of course, you know that the moment I move them, and place in a nice
> box - they will quit ! !
>
> See you later
>
> Mitch
>
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