That is what I guessed. I don't have a manual, just the tube datasheet ;)
----- Original Message -----
From: Carl <km1h@jeremy.mv.com>
To: n8de@thepoint.net, Paul Decker <kg7hf@comcast.net>
Cc: amps@contesting.com
Sent: Tue, 19 Mar 2013 21:32:40 -0000 (UTC)
Subject: Re: [Amps] SB-230 Power Question
I guess you guys didnt read the manual either (-;
The input is a bank of resistors to swamp power and the manual states 100W
drive but I dont run them that hard as the cooling is marginal without a fan
on the heatsink.
About 500W is safe and sane unless you have a lot of extra cash.
Carl
KM1H
----- Original Message -----
From:
To: "Paul Decker"
Cc:
Sent: Tuesday, March 19, 2013 4:52 PM
Subject: Re: [Amps] SB-230 Power Question
> Paul,
>
> I agree, though I didn't notice that earlier.
>
> 73
> Don
> N8DE
>
>
> Quoting Paul Decker :
>
>>
>> I admit, I don't know anything about the SB-230, but 100W drive seems
>> excessive for an 8875/8874, is there some sort of attenuation for the
>> input?
>>
>> My 432 MHz amp using a single 8874 tube takes 25 drive to produce 500W
>> out.
>>
>> Paul,
>> KG7HF
>>
>>
>>
>>
>>
>>
>> Date: Tue, 19 Mar 2013 00:55:42 -0700 (PDT)
>> From: K4MT
>> To: "amps@contesting.com"
>> Subject: [Amps] SB-230 Power Question
>> Message-ID:
>><1363679742.11720.YahooMailNeo@web120205.mail.ne1.yahoo.com>
>> Content-Type: text/plain; charset=iso-8859-1
>>
>> I recently acquired a SB-230 thinking the tube was probably bad with an
>> idea of doing a GI7B project. To my surprise the amp puts out 650 watts
>> plus on my peak reading wattmeter on SSB 80/40 Meters with 100 W
>> drive..
>>
>> On the bands from 20 and up the power output drops. ?20 Meters is about
>> 550, 15 meters about 350-400 and I ?have not tried 10m. ?
>>
>> I recapped PS, rebuilt tube grid circuit and repaired some bad
>> soldering and out of tolerance parts, replaced grid bypass capacitors,
>> removed entire tank circuit and band switch. Cleaned bandswitch and
>> cleaned/resoldered all connections.
>>
>> Still power on higher bands drop as above.
>>
>> Any experts on this amp out there who might have an idea what might be
>> going on. Is this a sign of a weak tube? ?Since I get so much power
>> output on 80/40M I would think the tube must still have some life in
>> it.
>>
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>>
>
>
>
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