Re: amp question

[The Bernadettes <mdestefano@xxxxxxxx>]

Jeff,
    Could very well be the power tubes, fluctuating volume is an indication
of deteriorating power tubes.  Another thing, being a BF means the amp is
pushing 40 years old.  The power supply dropping resistors are getting old,
excessive heat and wear can cause them to "drift" in resistance altering the
power, voltage, and gain to the pre-amp tubes.  It's a general practice of
mine, whenever I service an amp, is to replace the old 1 watt carbon comp
power supply resistors with 3 watt metal oxide resistors which are much more
thermally stable.  I usually do this when I do a cap job on an amp.  Has
your amp had a cap job recently?  If not that would be a good idea to go get
a general servicing, and cap job.  Could also be the output transformer,
which is the large "silvery" transformer (not to be confused with the
largest black transformer, which is the power transformer).  At the end of
the night, touch the transformer with your finger, it should be warm, but
not so hot that it burns your finger.  If it is, that could be part of the
problem.

Could also just be your ears, it's known that your ears can become somewhat
"tired" or "numb" after  extended exposure to high sound levels, that's why
bands seem to get louder as the night goes on!

As far as replacement 6V6's, go with quality NOS if you can afford it, or
Electro-Harmonix of the current production models, anything else will blow
in a Deluxe due to the high plate voltages.  Angela at:
http://www.angela.com has a nice selection of NOS 6V6's at reasonable
prices.

Regards,
Don D.

Linda Delong wrote:

>   I have a question for you amp techs out there.I play with a CR bullet
> through a Harp Commander into a BF Deluxe.The tubes in the Fender are in
> stock configuration.I'm very happy with the sound of this setup, but
> after the amp has been on for a couple hours, it seems to lose a little
> volume without changing any settings.Is this a sign of a developing
> problem? The change is slight so it might just be my old ears playing
> tricks on me but I think it's real.The power tubes are about 3 years old
> and I use the amp 3 to 5 hours a week - should I replace them?Other than
> replacement tubes and speaker, and a 5meg input resistor the rest of the
> amp is stock.Any advice or comments would be appreciated.
>                                                 Thanks,
>                                                          Jeff
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