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A neat panel-mount pot
Posted:
Tue Sep 18, 2007 2:40 amby kheper
Here is a nice, compact pot -
http://www.vishay.com/docs/51036/p16pa16.pdf
The cost is about $7.
But, it is only rated at 1W. For a bias control
would this pose any problems?
My bias voltage will be -89V and draw no
more than .100A.
Posted:
Tue Sep 18, 2007 6:25 amby Shannon Parks
Pretty sweet looking bias pot. I think that looks to be a great part for those purposes. Does Mouser carry them?
Nice!
Posted:
Tue Sep 18, 2007 6:29 amby EWBrown
Most bias pots handle far less than one watt, so these should be fine, for fixed or the ST-35 adjuatable cathode biasing. The little multi-turn trimpots are usually less than one watt capability.
I would't connect the entire -89V directly across the pot, use series resistors to narrow the adjustment range, centered around the desired voltage level.
HTH
/ed B in NH
.
Posted:
Tue Sep 18, 2007 6:39 amby kheper
Posted:
Wed Sep 19, 2007 6:49 pmby Brik
Hi,
I have four of these for a fixed-bias KT-88 push-pull amplifier which is under construction. These pots are of high quality, rugged, and compact. The only concern I have is that, if the knobs are exposed, it may be too easy to accidentally change the bias setting with the slightest of contact.
/brik
Posted:
Thu Sep 20, 2007 7:56 amby EWBrown
You could use a couple of stand-off spacers and a clear plastic / lexan cover of some kind to "protect" the pots once they are set. Prevent's accidental bias "adjustments" and shouldlook OK as well...
/ed B in NH
Posted:
Fri Sep 21, 2007 5:27 pmby Brik
Hi Ed,
Thank you for the "guarded bias pot" idea. I have been in search for an optimal compromise between decent accessibility and protection from accidental re-adjustments for these pots.
One other problem with these cuddly pots is that they tend to invite unwanted attention.
One of the first thing a 10-year-old did to the mock up of the amplifier was to turn the knobs on these pots. Yellow_Light_Colorz_PDT_21
/Brik
Posted:
Sat Sep 22, 2007 3:05 amby kheper
You could mount the pots on a sub-panel
inside the chassis of the amp, but that would
defeat the 'aesthetic' purpose of these pots.
A big cage over the entire chassis of the amp
or a small cage over the pots would also
deter those who like to monkey around with
electrical adjustments from doing so.