Don Thanks for the video and the noise comparison with your other amplifiers.
I've had my KPA1500 (s/n 083) a few weeks and have enjoyed using it on the air, as well as subjecting it to IMD and other tests at a variety of power levels. Individual tolerance of acoustic noise varies and I put myself in the "sensitive" category. When I first set up the amplifier and power supply, I realised that I was going to have to do something more than simply stacking the units alongside my operating position: the PSU fan was just too annoying. Lacking any immediate "remote" options, I settled for putting the PSU on top of a small chest of drawers, located under my operating desk, which is made of thick, dense laminated particle board. The room is carpeted, and rather dead acoustically. I found that acoustically shielding the PSU helped enormously, while the chosen position still allows good airflow and access to the PSU. I did also experiment with some heavy felt drapes pinned under a section of the desk but, when the airflow to the PSU was good enough, there was no worthwhile improvement over just positioning the PSU under, and slightly towards the back, of the desk. As far as the RF deck fans go, I can live with the Level-1 speed but, in situations giving more than an occasional burst at Level 2, I'd be looking to locate the unit further from my desk. I do wear headphones from time to time, and that would certainly help with the acoustic noise issue, but it wouldn't be a long-term fix in my circumstances. The upside is that Australian power levels, and my operating modes, mean that the RF deck fans do not routinely get beyond Level 1. Even when doing the dummy load tests mentioned earlier, I paused the measurements if the fans hit Level 3. I'd add that the KPA1500 is likely one of a very small number of amplifiers of its class suitable for desk installation in my small shack. Notwithstanding my earlier comments about noise, I find it a nicely engineered product which meets my requirements for a high power, solid state gain block for use with a variety of exciters. My other amplifier is a Collins 30L-1 (4x811A), which now sits permanently attached to an S-line station. Fan noise was never a problem there, but 30L-1 cooling is less than generous, being helped by a single fan, the motor of which has aptly been described as a refugee from a record player. As an aside, I'm looking forward to the KPA1500 firmware upgrade, having also identified the occasional SWR bar graph errant excursion as most likely a firmware bug (aka algorithmic anomaly). 73 to all, Peter. -----Original Message----- From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On Behalf Of Don Butler Sent: Saturday, 2 June 2018 2:01 PM To: 'Richard Thorne' <rtho...@rthorne.net>; Elecraft@mailman.qth.net Subject: [Elecraft] KPA1500 Fan Noise Video posted In response to N5ZC’s request I just made this short video to provide a listen to the KPA1500's fans ... at least as they sound in my shack. Follow this link to view: https://vimeo.com/273064144 In addition to the KPA1500 the video also includes footage of my Alpha 9500 and Icom PA1 … each running with their fans at maximum speed … to provide a simple rather crude comparison. What do I think? I think that fan speed 1 and fan speed 2 on the KPA1500 are probably comparable to the fans that are installed on the other amplifiers as far as sound and efficiency are concerned and likely provide a similar degree of cooling at those speeds. And, I think that fan speeds 3, 4, and 5 (which are indeed noisy) provide the KPA1500 with enhanced cooling capability that is simply not available on other amplifiers. Don, N5LZ -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Richard Thorne Sent: Friday, June 01, 2018 5:55 PM To: Elecraft@mailman.qth.net Subject: [Elecraft] KPA-1500 Fan Noise - YouTube ? This fan noise issue has me concerned to the point that I’m considering cancelling my order. While the amp won’t be on my operating desk, it will be on a rack next to my operating desk. Remoting the amp is not an option. Quite frankly I have no interest in remoting the amp. Is there anyone out there that has a KPA-1500 willing to post a YouTube video so we can hear the fan in action and judge the noise for ourselves? From the research I’ve done it appears that if you want a solid state amp, regardless of make, you need to be prepared for fan noise. Thanks Rich - N5ZC Sent from my iPhone ______________________________________________________________ Elecraft mailing list Home: http://secure-web.cisco.com/1uRicXx-_Puaj7NVyHg6rvgshCBkUB1TffrwYj7wmeFFDVPDyas0VC_90RJ6K5pydwXLNpIRxu9BzTR_slYqeGjwV-CpOqKmyTxKfAIeVYJgIRqhNBVvcK_8ZbYLR0gNksxAqfE27Y8UcAoCYOY7tD3yIXuRxFM0ci0OioA0ZPL1_8-ZWE8324rzxZTmh3gHeh0DQdXwSZXA0xHb_j4dPwdlyVXZ2eeMQWVCRNMh6gnPg8y2TIx2k9prPl_qssYRS8aGoCm9j3bQgK0LmhUH6_BZpd88WN6ZxzeW1ilz-pPSSTGfzfUUzrE0ENskH5R1xzlpPstch5T6qEH0YqyfQJixEkVoTeIbn8DHJW4kXyiVCZyL1HuM6RkiHVtGgPSZlwRqBq3bnJbjORp-SPtoW4i35D8dgI52T99MZ6ENdxm8spJ3ET0Fse797DJyyo0Mbb4cHMa361gdFrl6w9Hz4wUT4a5yghkBlBHBh8boC8SU/http%3A%2F%2Fmailman.qth.net%2Fmailman%2Flistinfo%2Felecraft Help: 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