Thanks everyone for participating in this disscussion . This problem is in a
liniar amplifier . The plate that glows red is the driver tube . The tube is a
6LX6 and is not that expensive . The 4 driven tubes are 8908 tubes and are$
93.00 each . Anyway all the tubes are designed to have 6.3 v. to power the
filaments . Like I said , the voltage coming from the transformer is 7.2v. These
voltages were all checked on the bottom of the tube sockets .
I feel that being the voltage is so high on the filament that it is making the
tubes over conduct and saturating the plate .
I will buy a filament transformer and see if this clears the problem .
Thanks to everyone who participated in this discussion , Rick

"Jerry G." wrote:

A thing to also consider, is that the heater transformer has some internal
resistance, and there is some resistance in the wiring from the transformer
to each of the tube heaters. You must not read the transformer output with
no load. In the engineering of the system, assuming it is properly designed,
there should be compensation for the transformer winding resistance, and for
the resistance in the tube heater wiring.

In a properly designed system, the transformer heater output should come to
a main terminal, and each of the heater's wires pairs should be spidered out
from that point.

In the lower cost daisy chain type of wiring, as what has been done on low
cost consumer tube equipment, they were daisy chaining a single pair of if
wires around the chassis to distribute the heater supply. This is not a good
practice, especially in high a design where the loading is of high current,
or where the best possible heater supply stability is required.

--

Jerry G.
======

"rijo1" wrote in message
...
Hi group , I have a project that has a transformer with an output
voltage of 7.3 volts AC that drives 5 tubes . The correct voltage to
drive the tubes is 6.3 volts AC. This is used in a RF circuit and I need
to step down or reduce the voltage from 7.2 volts down to 6.3 volts
directly from the transformer lead .
What would be a simple way to reduce the voltage to 6.3 volts without
replacing the transformer ?
Please give details as clear as possible . Thanks for any good help
in advance .
Rick