[Heathkit] Amp question. Was: watering down scotch...
Walt dabell
walt at dabell.org
Wed May 9 09:08:27 EDT 2012
I was quite content not adding to off topic discussions,
but this has gone over the line...
Water in your Scotch? Blasphemy!
Now, on to a radio topic. Well, amp. I joined this list
because of my Heathkit SB1000, which is still working fine.
It is my Kenwood TL-922 that is having issues. Sorry this is
also off the Heathkit topic, but hopefully this is a generic
enough of a question that this group might be able to offer
some comments or advice.
I recently discovered the amp I picked up last summer had the
80m contact on one of the wafers missing. Burnt offerings to
the God of Switch from the previous owner... The amp never
would tune right on the low bands, now I know why.
After replacing the band switch, I'm still having an issue
with the amp (2x3-500z's). It nears the low end of range on the
tune capacitor to get full output on the low bands. 160 is at
0 (and is probably not at full output) on the tune cap, 80 and
40 are between 0 and 1, but do tune.
It looks to me like it has too much capacitance in the output pi.
I tried to verify this by scabbing in a 100pF doorknob of suitable
RF quality to the 80m cap and it made things worse. took it back
out and things improved to where they were.
Assuming my assumption is correct, that it looks like the amp,
on low bands, has too much capacitance, why? Could this be a sign
of a softening tubes? Or perhaps the padding caps for 80 and 160
being cooked off of (over) value? I would think they would
decrease in capacitance if cooked, not increase.
Thoughts or ideas?
Thanks!
Walt Dabell - W3WMD
On 5/9/2012 7:43 AM, David C. Hallam wrote:
> Why in the world would someone want to drink triple distilled spirits?
> You might as well drink vodka. The best whisky in the world comes from
> the island of Islay and you can taste the peat smoke and brine. About 2
> ounces of Laphroaig in a heavy crystal glass with a small splash of
> spring water and sit down and relax.
[...]
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