[Amps] filament instant heating query

[Carl]

5.4 to 5.5 on a typical modern AC line. Its hard to get below 500ma even at 
70W drive.

Carl


----- Original Message ----- 
From: "Rob Atkinson" <ranchorobbo at gmail.com>
To: "Carl" <km1h at jeremy.mv.com>
Cc: <amps at contesting.com>
Sent: Friday, June 15, 2012 2:18 PM
Subject: Re: [Amps] filament instant heating query


> Didn't know that.  I always figured the AL-80s were simply over driven
> so the Ip went way over 400 ma.  I have heard of owners having to get
> a new tube every 3  years or so.  What is the stock fil. v.?
>
> tnx
>
> Rob
> K5UJ
>
> On Fri, Jun 15, 2012 at 11:34 AM, Carl <km1h at jeremy.mv.com> wrote:
>
>> Now you take a poorly designed/marketed amp such as the AL-80A/80B which
>> runs the filament voltage high to start with so it can meet its inflated
>> 1000W PEP rating. The end result is that it forced a step start to be
>> included in late AL-80A production and all 80B's. The filament is still 
>> over
>> spec in standby using the factory set transformer taps and using a 
>> bucking
>> winding will bring it down to 5.0 no load at the socket and 4.8V at full
>> power out.The end result is a bit less RF but hopefully much longer tube
>> life.
>>
>
>
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