[Amps] 8877 Filament choke

[Bob Maser]

Beats me.  I've never been on 6, not since 1961 anyway.  A lot of builders 
install a filament choke on a 8877 amp, example my Henry 4K Ultra, which 
runs a single 8877, had a filament choke.  I'm not sure about an Alpha 77. 
I have always been told that in the HF region running a 8877, you don't need 
one in the filament circuit but a 2.5uH choke is required in the cathode to 
bias line.  Bill Orr shows this in his 21st edition (1978)Radio Handbook on 
page 22.41.  If you don't already have some of Bill's old handbooks start 
looking for one if you're serious about amp building.

Bob W6TR
----- Original Message ----- 
From: "Roger" <sub1 at rogerhalstead.com>
To: "Bob Maser" <bmaser at tampabay.rr.com>; "Rick Stealey" 
<rstealey at hotmail.com>; <amps at contesting.com>
Sent: Thursday, November 15, 2007 5:41 PM
Subject: Re: [Amps] 8877 Filament choke


>
>
>
>> With an indirectly heated cathode you don't need a filament choke, in the 
>> HF
>> region.
>
> What about when running one on 6-meters?
>
> Roger (K8RI)
>
>>
>> Bob  W6TR
>> ----- Original Message ----- 
>> From: "Rick Stealey" <rstealey at hotmail.com>
>> To: <amps at contesting.com>
>> Sent: Thursday, November 15, 2007 9:26 AM
>> Subject: [Amps] 8877 Filament choke
>>
>>
>>>
>>> Info in the ARRL handbook seems to indicate that it might be better to 
>>> not
>>> use a filament choke on an 8877 amplifier, that it might cause more
>>> problems than it solves.
>>> I wonder what you guys who have homebrewed 8877s think?
>>>
>>> Rick  K2XT
>>>
>>>
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