[Elecraft] 2nd Report

[Bob McGraw K4TAX]

Although making things a bit larger physically, fans enclosed into the 
equipment case, thus providing some acoustic dampening, and configured 
to pull air into the case {along with much of the noise} and exhausting 
air and noise through several ports is more applicable to reducing 
overall noise.  High volume air moved at slow rates is much quieter than 
the same amount of high volume air moved at faster rates.    Also, fans 
with a lower blade tip velocity makes less noise.

As I indicated in an earlier post, some fans are more efficient at 
"blowing" i.e pressurizing the enclosure, while others are more 
efficient at "sucking" thus evacuating the enclosure.  In general, sound 
moves with the air flow.

73

Bob, K4TAX


On 5/28/2018 10:10 AM, Drew AF2Z wrote:
> No KPA1500 here but I did replace the fans on my lil' ol KPA3 with 
> Noctuas. They are noticeably quieter. If there is a suitable Noctua 
> replacement for the KPA1500 fans you might want to compare the sound 
> level specs to the Sanyo Denkis.
>
> Wonder if it would be possible to build an active noise cancelling 
> system into the rig itself; seems like it would work in that enclosed 
> space...
>
> 73,
> Drew
> AF2Z
>
>
>
> On 05/28/18 10:20, Richard Zalewski wrote:
>> First major contest with KPA-1500. Overall VERY pleased.  No glitches
>> other than a few operator errors early in the contest.  Loving the amp.
>>
>> Fan noise...another issue.  Usually for a cw contest I use some old ear
>> buds.  Not possible with the amp.  Had to use the total ear muffs and 
>> still
>> quite noisy.  Did not effect my performance but it is annoying. I can 
>> not
>> imagine what it was like before they released the amp to general public
>> when they changed the fans...made them less noisy???  Still needs 
>> some work
>> but at this point probably not possible.  So looking for suggestions for
>> reasonably priced noise cancelling headset with mic if possible.
>>
>> Hope we get full explanation of what gets changed in the next firmware
>> release.
>>
>> Still smiling.
>>
>> Richard
>> *W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU,
>> J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV
>>
>>
>> *Be joyful in hope, patient in affliction, faithful in prayer*
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>
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