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[Amps] Gettering 4CX800A GU74b

To: "Harold B. Mandel" <ka1xo@juno.com>
Subject: [Amps] Gettering 4CX800A GU74b
From: Jason Buchanan <jsb@digistar.com>
Date: Thu, 21 Oct 2004 06:14:42 -0400
List-post: <mailto:amps@contesting.com>
Harold B. Mandel wrote:

After trying out an EMTRON DX-3 and finding it
prone to self-oscillation without any neutralization circuitry
and susceptible to RF Feedback at 18MHz, (enought to illuminate
all the LEDs on the bar graphs, all at once),

And in addition to finding a tube socket that was ancient and
a 12 year old tetrode in a supposedly "new" amplifier, I wonder
what kind of surprises awaits owners of the DX-4?????




Can't comment about the rf feedback setting up a carnival light show on 18MHz but i've seen a few new amps shipped with pretty old tubes. Zillions of these tubes built in the early 90s. Ray Cronin makes special mention of the warranty going bye-bye if you put another tube in your qrotec amp that you didn't buy from qrotec - they supposedly stoke up the getter and burn them in good and long.


http://www.qrotec.com/tubewarn.html

IF YOU USE TUBES OTHER THAN THE ONES DELIVERED WITH YOUR AMPLIFIER, QRO TECHNOLOGIES IS NOT RESPONSIBLE FOR ANY DAMAGE CAUSED BY THOSE TUBES. YOUR WARRANTY WILL BE VOID AS IT RELATES TO ANY DAMAGE CAUSED BY THOSE TUBES. YOU WILL BE RESPONSIBLE FOR THE REPAIR COSTS AND RETURN SHIPPING.

THE 4CX800A (GU74b) TUBE MUST BE PROPERLY GETTERED AND TESTED BEFORE USE. THE TUBES SUPPLIED WITH OUR AMPLIFIER HAVE BEEN GETTERED AND TESTED. TUBES SUPPLIED BY OTHER VENDORS HAVE NOT BEEN PROPERLY GETTERED AND TESTED. THESE TUBES HAVE A STRONG TENDENCY TO ARC CAUSING DAMAGE TO THE AMPLIFIER. WE STRONGLY URGE YOU TO MAKE SURE ANOTHER TUBE SUPPLIER GETTERS AND TESTS THE TUBES HE SELLS AND GUARANTEES THOSE TUBES.

73s

Ray W. Connin, KB8VU
QRO Technologies, Inc.


This seems reasonable to me - and as long as they're not pushing up the price of hand-gettered replacement tubes so much the better. ("Would you like to supersize that amplifier?")



73 Jason N1SU _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps

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