Is that one 8877 per 3-500 as in my SB220?
Sent from my iPhone 6s+
> On Dec 4, 2016, at 7:41 AM, Bill Turner <dezrat@outlook.com> wrote:
>
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
>> On Sun, 4 Dec 2016 06:13:07 -0600, you wrote:
>>
>> Ok but some of us are about on our last go-round. What do we do for our
>> thousands of SB 2nn series Heath amps??
>> 73
>> K5DAM
>
> REPLY:
>
> If it were my SB 2xx amp I would replace the 3-500(s) with a single
> 8877. It is a smaller tube so it should fit OK, and a single 8877 has
> more power capability than a pair of 3-500's and needs only about half
> the drive for the same output. The filament voltage is the same and
> filament current is less, so no change is needed there.
>
> I have never actually done this so there might be a gotcha I'm not
> aware of and you would need to proceed carefully, but if successful
> you would have a much better amp. More headroom, better reliability,
> less drive and in most cases an 8877 does not need a parasitic
> suppressor. My homebrew 8877 amp does not have one and is perfectly
> stable on all bands. I have seen numerous other 8877 designs that do
> not have one either.
>
> Making a change like this is not for the inexperienced and if you are
> unsure about it, you should probably find an Elmer to help you.
>
> 73, Bill W6WRT
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