[Elecraft] K2 / K3 audio - and the K2 fan

[Phil Wheeler]

Ted,

I have a fully-developed K2 #380) including 
KPA100, KAT100, KDSP2, etc.  I've even added the 
3rd party MA Board and the Rework eliminator 
(together). I also did a full update of everything 
in 2014 (ROMs, some updates I'd not done when last 
I worked on the K2 in 2004 or so, etc.; it was 
quite a job and my Hakko desoldering tool proved 
its worth!)

The K2/100 and KX2 are my in-the-back-bedroom 
setup: Takes less space on my smaller desk, and 
I'm able to use any antenna by throwing switches 
out in the shack. Mostly of late I use the QRP 
KX2; sort of more fun. My shack off the garage is 
not heated and not insulated: Too hot on hot days, 
and too cold on cold days; the shack is better 
equipped (KX3/PX3 and K3/P3/KPA500/KAT500) but not 
always pleasant to use.

I have listened to both the K3 and K2 alternately 
side by side in the shack, in fact this morning. 
They do sound different, but I can't say one is 
better than the other. Of course, since use DSP 
filters in the K2 all of the time, and in the K3 
most of the time, that's a variable unique to me 
and my filter settings.  The K3 is easier to 
operate, especially on SSB, due to the P3; I have 
no panadapter set up for the K2, one of the few 
third-party options I've missed.  One of these 
days I may replace the K2/100 with a more 
state-of-the-art radio; I started building mine in 
July 1999 and the design is a bit long in the 
tooth, but still solid today!

Since I've had no issues with my KPA100's fan, 
noise or otherwise, I wonder if you should 
consider replacing yours, Ted?  Of course, one ear 
has stone deaf for 50 years and the other one is 
not spectacular (Advantage: No need for subRX in 
K3!), but I do hear computer fans, the fan in my 
power supply, etc. -- so I'm not "fan deaf"

73, Phil W7OX

On 6/26/16 3:56 PM, Dauer, Edward wrote:
> I know this is runs the risk of reopening an old thread, so I’ll keep the question focused:
>
> During the FD this weekend I spent about half the time with the K3 line, and half with the K2.  Using the same headset, same antennas, same ambient environment, but of necessity different filter configurations, I now understand why some people prefer the K2’s audio to the K3’s.  It is a matter of taste, of course.  But I found the K2 simply easier to listen to for long stretches – at least for my ops which are CW only.  It’s hard to describe the difference in words, so two questions.  1.  Has anyone done an analysis of the frequency response of the audio stages in both rigs, to compare them empirically?  My guess is that the K2’s curve is skewed toward the lower ranges.    2.  I have never set the RX EQ in the K3 – it’s still on what it was when I bought it.  Has anyone tried to make a K3 sound more like a K2?  If so, what settings do the best?
>
> This encomium for the K2 ends, however, when it hits the fan.  Running QSOs in the contest with the K2 and KPA100/KAT100 (in an EC-2) kept the amp’s fan on pretty much continuously – and the sound it makes is something like a cat being slowly tortured.  It is much more annoying than the fans in the K3, the KPA500, and the K3 power supply blowing simultaneously, which they almost never do.  Could be a bad bearing?  The amp hasn’t been used for 100 hours yet.  If it’s not a flaw, is there an after-market fan that fits the KPA100 cutouts and which moves as much air but doesn’t make as much noise?
>
> Thanks . . .
>
> Ted, KN1CBR