A neat panel-mount pot

[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.

[Shannon Parks]

Pretty sweet looking bias pot. I think that looks to be a great part for those purposes. Does Mouser carry them?

[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

.

[kheper]

Yes. The Mouser PN is:

72-P16NP-10K

$7.64

http://www.mouser.com/search/ProductDet ... -P16NP-10K

[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

[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

[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

[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.