[Amps] LK 550-ZC

[Rob Atkinson]

What modes do you operate?  How long are your transmissions?

73

Rob
K5UJ

On Sat, Mar 17, 2012 at 11:29 AM, Dick Green WC1M <wc1m73 at gmail.com> wrote:
> Are you basing this on fact or speculation?
>
> I was very careful to measure the tube temperatures at the highest
> acceptable duty cycle both before and after the mod. I'm confident that the
> modification I made is both safe for the tubes and acoustically superior to
> the original design.
>
> Remember, my LK-550ZC has a thermal sensor that will kick the fans into high
> speed as needed. If it's not switching to high speed because I increased the
> fan speed at the low-speed setting, then that's a good thing. If my
> reduction of speed in high-speed wasn't effective, then the amp would spend
> more time at high speed. It doesn't.
>
> 73, Dick WC1M
>
>> -----Original Message-----
>> From: Rob Atkinson [mailto:ranchorobbo at gmail.com]
>> Sent: Saturday, March 17, 2012 8:19 AM
>> To: Dick Green WC1M
>> Cc: Carl; Paul Kraemer; AMPS
>> 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.
>> >
>