On Aug 9, 2005, at 5:31 PM, k7rdx wrote:
> I was impressed the first 3KA I worked on by the sheer size of the
> tank circuit components as well as the input network layout.
The weak sister in the 3K-A is cooling. The el cheapo blower does not
produce enough air pressure to keep the red paint on the tubes from
charring to brown. Also, the solder in the tube pins #s 1 and 5 tends
to melt and run out during a contest. Other problems are: lack of a
glitch-R in the +HV, use of high-Q VHF parasitic suppressors and weak
3-500Z socket springs - which exacerbates the solder melting problem. .
> The thing that really looks out of place is the 3-500z tubes...It
> seems to me 3cx3000a7 would look right at home in there, or a pair of
> 3cx1200A7s
.... or a pair of 8877s ... (which has been done, I think by W6RU)
> Bet you wouldn`t flat top those tubes in the old Henry..Jim.
> ----- Original Message -----
> From: Joe Isabella
> To: k7rdx ; Gudguyham@aol.com ; amps@contesting.com
> Sent: Tuesday, August 09, 2005 9:59 AM
> Subject: Re: [Amps] RF Parts OEM 3-500ZG's
>
>
> Remember, the 3K-A was designed as a commercial/government use amp.
> It has no standby switch, and is built pretty stout (weighs nearly
> 200lbs.). I'm about to take mine down to give it a good cleaning, add
> 160m to it, and add some relays so I can remotely control the fils,
> blower, and put it in standby when not needed. I've seen RFP 3-500ZGs
> do nearly 2500W out in another Henry amp that was modified -- I'm sure
> it was pretty dirty at those levels, but hey, who cares during a
> contest, right??
>
> And like I said before, if you think 3-500s aren't good for 1kW PEP,
> tell Ameritron...
>
> :-D
>
> Joe, N3JI
>
>
> k7rdx <k7rdx@earthlink.net> wrote:
> Some of the older Henry 3k amps had current limiting in the psu
> negative and
> required 100+ watts drive for just 1200 or so output (Easily
> disabled).2K
> output(Very possible) from a Henry equipped with 3-500z tubes
> seems a bit
> excessive to me,especially if your`e concerned about keeping
> neighbors and
> fellow hams happy..Jim.
> ----- Original Message -----
> From:
> To: ;
> Sent: Monday, August 08, 2005 7:58 PM
> Subject: Re: [Amps] RF Parts OEM 3-500ZG's
>
>
>>
>> In a message dated 8/8/2005 11:56:52 A.M. Eastern Standard Time,
>> n3ji@yahoo.com writes:
>>
>> Maybe you should try it with **TWO** 3-500ZGs, like my Henry runs. It
> will
>> provide nearly 4kV at 1A with Peter Dahl upgrades.
>>
>> Joe, N3JI
>>
>>
>>
>>
>> I wont comment on the first sentence, but the 4KV would probably have
>> to
> be
>> under load. Most amps except for your Henry WONT give 4KV under load.
> Any
>> other amp except one like yours will not produce that kind of power
>> from
> 3-500s
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Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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