From memory:
The plastic encapsulated output relay on the 3 holer, totally fused on 4
occasions. The little diode in the bias/metering circuit, 3 times. The
filament voltage is 10% high on both models, on the 240V tap, running on
240V, so the tubes wear out like nobody's business. The plate coupling
capacitor failed once.
Having mains AC, Filament AC, DC, RF and HV all on the same circuit
board is questionable engineering practice and makes it a PITA to
service and all but impossible to insert resistance into the filament
line, to reduce it back to a sensible level.
I agree. The 811 is a wonderful tube but the 811 amps are truly price
built amps.
It is not the tube's fault. It is the marginally rated components, the
stresses placed upon them by the designers, and the cheap charlie
construction that make those amps the POS that they are.
Also, it must be remembered, that most appliance operators have no idea
how an amplifier works or how to run it and look after it. They are
very unkind to amplifiers. Models like the 811 series, have no chance
against these operators. :-)
73, Alek.
VK6APK
On 23/01/2015 9:09 PM, Roger D Johnson wrote:
What was breaking down? The 811 is a good tube but most hams believe
the mfrs
claims and run them way beyond their ratings.
73, Roger
On 1/23/2015 7:09 AM, Alek Petkovic wrote:
You said it in one Jim.
If you buy a AL811, you deserve what you get.
A guy local to me had two of them. One with three tubes and one with
four. They were forever breaking down and he usually brought them
around for me to fix.
In the end, I reminded him that he earned really good money and that
he had a really great station except for his amplifiers and that he
should just dump them and get something decent. Thankfully, he did.
Dunno what he runs now but I know it ain't the 811 amps.
Alek
VK6APK
On 23/01/2015 7:24 PM, Jim Thomson wrote:
Date: Fri, 23 Jan 2015 13:37:00 +0800
From: Alek Petkovic<vk6apk@bigpond.com>
To: Amplifier Mailing List<amps@contesting.com>
Subject: Re: [Amps] 5 Minutes for Ameritron 811H to warm up?
Yeah. Well that is strange. Blowed if I know what he means then.
Thanks
Alek. VK6APK
## Buy it for a song..then spend 15 mins to repair it. What takes 5
mins to
warm up, the fils...or the B+ ?? I think the xfmr in the 811 has
the fil winding
built into the plate xfmr. It could be some shorted winding issue,
etc. It could
also be a screwed up hv meter.
Jim VE7RF
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From sunny Binningup, Western Australia.
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