[Elecraft] K3 Audio (WAS K3 eHam review after 2+ years)

Mon Jul 6 04:56:51 EDT 2009

Audiophile as a term means little in describing perceived sound quality, it
is usually only an indicator of cost and the degree with which buzz words
have overtaken logic, reason and physics. Among engineers who design the
stuff, audiophiles are held in low esteem....but catering to their excesses
and silly myths does pay the mortgage.

Rather than replacing the chain, the components already in place are
suitable for pleasant sonic experiences so long as there are reasonable
source signals, if the design goal is identified.  Just saying you want a
"better" audio path does not help, a DC-Daylight bandwidth and 0.005%
THD/IMD will not provide the experience you are probably seeking and
imagining when you say "better". If you are specific in your request, it is
not hard to set it up so your needs are met. But as with anything moving in
one direction means compromises in another, what are you willing to give up
as not being so important to you? The root source of the objectionable
quality is probably far removed from the audio chain, in or before the
detector.

The best fidelity I have in a communications receiver is a little DC
receiver with a good balanced detector. Despite having no selectivity or
features, listening to QRM and noise on that one with headphones is quite
pleasant and the lack of IMD allows the brain to focus on one of the many
signals in its bandpass with ease and lack of fatigue. That is an
interesting experience and does show that noisy bands and raw signals are in
some manner a high enough quality signal source if the receiver does not
introduce too much IMD and artifacts. How to accomplish that with the added
requirement of selectivity is the question. 

It is something I intend to play around a little with now that I have my
mini-lab set up in my kitchen in my small 18th century apartment in the
center of St Petersburg Russia. I keep bringing gear back in suitcases,
mostly the small items, each trip back "home" to California where I have a
suitable lab for both RF and primarily audio design/prototyping. I have been
able to bring about 300lbs of gear over the last 6 years including a Audio
Precision Dual Domain, a Motorola Service monitor, 2 Sound Technology
distortion analyzers and generators, HP spectrum analyzer, wave analyzer, a
vector voltmeter, and the usual stuff like scopes and meters.
There are lots of electronic hobbyists here and there are parts stores but
the selection of parts is limited. What surprises me most is the lack of
tubes. The largest transmitter tube company in Russia is here yet no one
stocks tubes. I was hoping for a good supply of the 3CX300A made by Svetlana
made here since several of my designs use that high power audio tube.
I have a K2 now but hope to get a K3 if I ever slow down on my other hobbies
such as going out partying several times a week until 6am or with acquiring
lenses for my camera. Good lenses make most Ham radio purchases look like a
bargain.

My background has primarily been the recording side of sound, that gave me
the money and time to pursue the design side as a semi-profitable hobby. A
few of my recordings are still heard on the radio every day years later and
2 of my power amps are still in production by high end "Audiophile"
manufacturers. First licensed at 10 in 1959, still fascinated by sending
things through the "ether".

By the way, just to start an argument....Ask an Italian or American who
invented radio and the answer will be the same. But wrong, that honor does
and should go to A.C. Popov who was a professor of electrical engineering
here in St Petersburg with practical applied systems being used by the
Imperial Navy for search and rescue predating Marconi's early spark
experiments. If you come to this fascinating, beautiful city be sure to
visit the world's largest communications museum, which houses the Popov
collection and the largest stamp collection in the world.

Stan
KM6XZ
St Petersburg

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of vk6av at yahoo.com
Sent: Monday, July 06, 2009 2:35 AM
To: Guy Olinger; elecraft-bounces at mailman.qth.net; no3m at no3m.net
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 Audio (WAS K3 eHam review after 2+ years)

Given the likely expense of. Real audiophile audio chain, I would happily
settle for a audiophile grade 'line out' which I would then run into a high
quality stereo amp. So the question is even an audiophile line out feasible
for a reasonable amount of $$ given we have to be limited to a 13 v power
supply?
Harris K9RJ K3 1855

Sent via BlackBerry by AT&T

-----Original Message-----
From: Guy Olinger <olinger at bellsouth.net>

Date: Sun, 5 Jul 2009 15:48:00 
To: <no3m at no3m.net>
Cc: <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] K3 Audio (WAS K3 eHam review after 2+ years)

On Sat, Jul 4, 2009 at 10:45 PM, E. Tichansky <ni3s at ni3s.net> wrote:

> Unfortunately, there IS a problem w/ CW audio in the K3, at least with
> both here (see concurrently running thread: K3 Audio Low Pass Filter).
> The sidetones generated around the 12 kHz DAC leak-through (+/- sidetone
> frq., ie. 500Hz)are clearly audible for me and rather annoying, enough
> so that I had to insert inline low pass audio filters on each radio to
> knock it down to make CW operation tolerable.  I was in correspondence
> about the issue back in Oct/Nov of last year w/ Elecraft.
>
> Regardless of the "60 db down" and other levels people have measured on
> those sidetones, I can hear it, even with as low a volume setting of
> around 9-10 o'clock.  Apparently there are others that can as well.  The
> majority of folks who own a K3, presumably yourself included, have a
> reduction or loss of hearing at high frequencies.  From that
> perspective, the audio is great!  However, not hearing it doesn't
> necessarily mean there isn't an underlying problem present, and those
> that wish to fix it aren't doing so out of "desire to tinker and change
> things."
>
Though I have the typical reduction in high frequency hearing at my current
age, I remember well being able to hear TV horizontal sweep frequency (15+
kHz) quite loudly walking into a room with a television on. I began to lose
that in my fifties. Due to some lab equipment at college, I know I could
hear 20 kHz, though not as well.

The DAC artifacts I see clearly on spectrum analysis down 60 would have been
20 db over my hearing floor, and annoying, as I had the typical reaction to
someone raking their fingernails down a chalkboard. Such a sound would
literally make my gums "vibrate".

However, I DO hear any intermod in 3-6 kHz over top of a 3 kHz bandwidth
signal, and it DOES make the audio seem harsh if there is anything there.

Does harshness make any difference in a contest?  Not really.  40m has all
kinds of annoying crud that comes in. Less crud if it's a K3.  40m is an
annoying band.

 From the CQWWCW 40m claimed 1728 QSOs, I lost only 15 busted/NIL, which I
credit to the clarity of the K3 listening to awful signals up close to
overpowering signals. Not that I wasn't trying hard to be accurate in the
contest, but this result simply stomps any prior personal best where I was
trying just as hard. The log also includes signals that pre-K3, I simply
would not have attempted.

We were all K3 at NY4A and the other bands/ops reflected like improvements.
It was no personal fluke.

Given that, I would have to say that the RX is an unqualified success in its
intended design.  But if Elecraft was to offer an audiophile upgrade to the
K3 audio, I would put it in -- not for contesting, but just for listening
pleasure.

I still far prefer my old tube 75A3 for SSB listening, echoing an
old complaint from audiophiles about anything transistor vs. anything
tubes.  But my K3 hears clearly and accurately much stuff that is inaudible
on the A3, and the skirts on the A3's mechanical filters are no match for
the K3 combined DSP and INRAD.

It would be really neat if somehow Elecraft could product audiophile audio
in the K3, but for the price spent, an admitted harshness is really
nit-picking.  I'll take a board with an intended audiophile outcome, and
complain about that if it misses, but I bought my current K3 for the contest
results.

73, Guy.
K2AV
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