[Amps] LK 550-ZC

[Carl]

At 100W drive the little extra power over 2 tubes is meaningless, pull one, 
slow the fan down, and enjoy that rugged PAC-5 transformer. Double check 
filament voltage at the socket and reduce to 5VAC no load if necessary.

OTOH if you have 150-200W available then watch out for serious RF.

BTW, Im buying PAC-5's.

Carl
KM1H

----- Original Message ----- 
From: "Rob Atkinson" <ranchorobbo at gmail.com>
To: "Dick Green WC1M" <wc1m73 at gmail.com>
Cc: "Carl" <km1h at jeremy.mv.com>; "Paul Kraemer" <elespe at lisco.com>; "AMPS" 
<amps at contesting.com>
Sent: Saturday, March 17, 2012 8:18 AM
Subject: Re: [Amps] LK 550-ZC


> If you have 3 3-500s to cool and you operate any serious duty cycle at
> what the amp is capable of you probably need the high speed and accept
> the noise problem.
> hams obsess about fan noise far too much if you ask me.
>
>
> 73
>
> Rob
> K5UJ
>
> On Sat, Mar 17, 2012 at 12:16 AM, Dick Green WC1M <wc1m73 at gmail.com> 
> wrote:
>> Guess I have a real late one: it has the fan speed temperature sensor. 
>> The
>> stock fan speed is too slow in low-speed mode, so the fan cycles low-high
>> constantly. And it's like a freight train at high-speed. I increased the 
>> RPM
>> at low-speed so it goes to high speed much less often. That didn't raise 
>> the
>> noise level very much. I also decreased the RPM in high-speed mode, which
>> reduced the sound considerably, but didn't appreciably affect the 
>> cool-down
>> time to low speed. I used a temperature probe to make sure the tube
>> temperatures stayed well within spec.
>>
>
>
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