[TenTec] Centurion Amp Woes

[Charles Delaune]

John,

I, for one, have never heard of "Instant On" 3-500Z's. But, that's besides
the point. My point is that if the amp has been designed properly and there
are no defective parts (one would think that that would be the case for a
new and $$$ piece of gear) I should be able to leave the amp on idle for a
week, much less a few hours, and not have it bite the dust! As for saving
energy...in my opinion, that's a trivial matter. Like you, I'm NOT
comfortable turning equipment off and on every time I want to
transmit/operate.

Charlie - N5BLY

 -----Original Message-----
From: 	tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of John K Gotwals
Sent:	Sunday, October 08, 2006 3:40 PM
To:	tentec at contesting.com
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 at bellsouth.net>
Subject: Re: [TenTec] Centurion Amp Woes
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
Message-ID: <070501c6eb0f$b1224dd0$0201a8c0 at 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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