Probably the best method is not the instant on but keeping the filament on at
a warm setting and turning off the high voltage supply. This uses minimal
electrical energy while keeping the cathode warm and ready to go when the
amplifier is turned full on!
Regards,
Jim NC9J
-----Original Message-----
From: john@gotwals.com
To: tentec@contesting.com
Sent: Sun, 8 Oct 2006 4:40 PM
Subject: Re: [TenTec] Centurion Amp Woes
I was intrigued by Rog's longevity recommendation for "Instant On" tubes,
since I use a Drake L-4B amplifier. For ordinary tungsten light bulbs the
bulb's life can be shortened by frequent turn-on/off due to the thermal
expansion/contraction of the tungsten filament. In addition to the two
3-500ZGs, my L-4B power supply has two series connected 50 watt bleeder
resistors which get exceedingly hot while the power is turned on, and I
would guess that thermal fatigue of these resistors might also be increased
by frequent turn-on/off.
I would be interested in other comments on the turn-on/off vs. leave it on
conundrum.
John, N9JG
-----Original Message-----
Message: 10
Date: Sun, 8 Oct 2006 15:26:45 -0400
From: "RB" <K9RB@bellsouth.net>
Subject: Re: [TenTec] Centurion Amp Woes
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Message-ID: <070501c6eb0f$b1224dd0$0201a8c0@k9rb8c670f7e81>
Content-Type: text/plain; charset="us-ascii"
[snip]
I also might suggest that with an amplifier using 3-500Z type "Instant On"
tubes, you will increase longevity of the tubes, as well as save on your
electric bill by turning the amplifier off whenever you do not anticipate it
use during the upcoming 10-15 minutes. Since the tubes require virtually no
warm up time, turning them off when not in use is a preferred mode of
operation. Just the 5 volts at 15 Amps of current to each tube calculates to
be 150 watts of wasted energy. Add the fan and HV transformer and you're
likely looking as 250 watts just in the standby mode that you have been
paying for, expended mostly in generating heat and contributing to shortened
component life.
[snip]
73, & Good Luck!, Rog-K9RB
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