[Elecraft] KPA-1500 power supply fan noise

[rocketnj at gmail.com]

Hi Eric,

My 1500 is s/n 423. I do think the power supply fans are a bit loud in standby. Is my amp prior to the resistor change?
I have added the load resistor in the field and done the sample out mod for adaptive predistortion in the field also.

73
Dave wo2x



-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of Eric Swartz WA6HHQ - Elecraft
Sent: Saturday, May 23, 2020 11:53 AM
To: Larry (K8UT) <K8UT at charter.net>
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA-1500 power supply fan noise

Hi Peter,

If the amp is on, there needs to be at least some PS fan activity at a low speed to cool the PS in idle. 

What s/n is your 1500? On later s/ns we changed a resistor in the ps fan circuit to slow them down a bit more. 

An alternative is to swap your ant 1 and 2 connections, putting the 6m ant on ANT 1. Then you can listen to 6m with the amp off. 

73,
Eric
elecraft.com
---
Sent from my iPhone 6S

> On May 23, 2020, at 8:10 AM, Larry (K8UT) <K8UT at charter.net> wrote:
> 
> Peter
> 
> I built a slightly longer cable to match the length of the control cable that came with the amplifier (about 3 feet longer if I recall correctly).
> 
> This allows the PS to operate "remote" in a closet with the door closed.
> 
> -larry (K8UT)
> 
> ------ Original Message ------
> From: "Peter Dougherty" <lists at w2irt.net>
> To: Elecraft at mailman.qth.net
> Sent: 2020-05-23 10:33:19 AM
> Subject: [Elecraft] KPA-1500 power supply fan noise
> 
>> Is there any way to power off the fans (or lower their RPM) on the 
>> PSU if the amp is in standby mode?
>> 
>> I would like to keep my rig on 6m throughout the day during the Es season.
>> The problem is my 6m antenna is on antenna port 2 on the KPA, which 
>> requires the amp to be powered up. I only need to TX when a new grid 
>> pops up, but I do like to monitor the band during the day while I'm 
>> working. My XYL is working from home, and is in the same room for 
>> about 9 or 10 hours a day, and the noise after 10 minutes was too much for her. Any suggestions?
>> 
>> Please-n-thanks.
>> 
>> ---------------------------------------------
>> 73 and Good DX
>> Peter, W2IRT
>> 
>> 
>> 
>> President, North Jersey DX Association
>> 
>> DXCC Card Checker
>> Letter O Manager, ARRL Incoming 2nd District QSL bureau
>> 
>> 
>> 
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