[K3] Audio circuit distortion

[Jim Brown-10]

On 7/23/2013 12:15 PM, Don Putnick wrote:
> It didn't compete with the <0.3% distortion of the Icom 756 Pro III.

Single numbers like this are quite inadequate to describe distortion.
There are MANY kinds, and many manifestations. THD is a particularly
poor metric for non-linearity, because some orders of harmonics are FAR
more audible (and unpleasant) than others, and also because it does not
include intermodulation. For example, there's a popular audio signal
processing tool that includes a knob called "warmth."  It ADDS 2nd
harmonic distortion. In general, higher order harmonics are audible are
MUCH lower levels because they are relatively un-musical.  Digital
distortions are also quite audible,and at relatively low levels, again
because they are not naturally part of speech or music.

I'm quite satisfied with the audio quality of the K3 once those early
issues were corrected. I've got a nice stereo rig to listen to music,
most of which is acoustic jazz. I completely agree with Wayne's design
priorities.

73, Jim K9YC
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[Rich Heineck]

That one reminds me of a story told some time back at one of our local
QRP group meetings.  One of the fellows once had a coworker who claimed
the source of the power significantly affected audio quality, and that
power from a hydro generator produced much cleaner sound  than power
from a natural gas power plant.  Apparently the guy was dead serious.  
It took quite a while for the laughter to die down...

73,
Rich AC7MA


On 07/23/2013 02:47 PM, Ron D'Eau Claire wrote:

> And there are those who spend hundreds of dollars on a-c power cords for
> their audio systems that have been cryogenically treated to "align the
> copper crystals to avoid turbulence in the a-c power flowing through the
> cord from the wall outlet".
>
> The problem is that human perception determines satisfaction, and perception
> is not always based on objective data.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Doug Person
> Sent: Tuesday, July 23, 2013 2:25 PM
> To: [hidden email]
> Subject: Re: [Elecraft] [K3] Audio circuit distortion
>
> I once wired a guy's $20K audio system with RG8.  He claimed it made all the
> difference.  He also claimed that vinyl was vastly superior to CD's.  I told
> him he had a wonderful imagination.  The very best and cleanest vinyl with a
> radial tracking arm turntable and a top of the line cartridge could just
> barely make a 40db s/n.  Digital audio can do 100db anytime.  Many years of
> selling audio gear taught me about the psychology of hearing.  It takes an
> experienced ear to appreciate a truly flat response. Most people prefer a
> very unbalanced equalization.
> I got lots of chuckles switching between a $300 system and a $3000 system
> and having most people prefer the cheap setup.
>
> Having designed loud speakers professionally (of which 1,000s were sold), I
> am equipped with very refined and experienced hearing. Unless you were
> listening to FM broadcast, how could you possibly appreciate a .3% THD?  I
> always assumed anything less than 1% was more than adequate for our kind of
> communications.  If we get down to this level of performance, we'll need to
> work on the 50% or so of stations that only concern themselves with output
> power - not audio quality.  There is a lot of dreadfully distorted signals
> on 20 meter SSB.  Nothing beats working a station that is s9+20 and barely
> understandable because he has compression and mic gain pushed up so he sees
> 1500 watts on his output meter all the time.
>
> So, IMHO, the K3 has absolutely splendid audio when I have a chance to work
> another station whose audio is actually adjusted correctly.  It amazes me
> that most rigs today have a monitor function.  Must be the most unused
> feature of all time.
>
> 73, Doug -- K0DXV
>
>
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[Arie Kleingeld PA3A-2]

The audio distortion of the K3...


One can laugh about this, but let us face it. There was a lot of
laughter about the reported audio artifacts coming from the first few
/thousand/ K3's. At first it was denied by many.
It took quite a while until people were convinced that it realy was a
problem to the ears of a group of people.

And yes, finally there came a decent modification in hardware and
software of the K3. That cleared the audio up and cured most of the
problems.

The K3 is a good rig, not a perfect one.


73
Arie PA3A



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