K2 vs. Drake 2B - New vs. classic.

[Darwin, Keith]

I had some fun today.  Hooked the K2 and the Drake 2B up to the same antenna and fed the headphone output of each into a mixer.  I could then tune them both to the same signal and switch back and forth quickly to hear them in the same headphones.  Interesting results.
 
Good:  The K2's selectivity is far better than the old Drake rig.  With the K2 at 1 KHz bandwidth and the audio filter off, the bandwidth was about the same as the Drake set to .5 KHz plus the 2BQ nearly maxed.  In other words, the Drake at it's narrowest is about as wide as my K2 at it's widest.  Narrowing the K2 to 600 Hz plus the audio filter widened the performance gap that much more.
 
Good: The K2's AGC is much smoother and more effective than the Drake's  The 2B gives a little *pop* on the leading edge of many strong signals and the AGC is aggessive enough that effective S/N ratio is rather low.  The rig actually sounds better if I ride the RF gain and turn it down to where the AGC doesn't have much left to do.  The K2's AGC just worked smoother and better.  S/N ratio remained high and leading edges were clean and clear.
 
Good:  The K2's frequency stability was better than the 2B (Duh!).  I noticed the 2B was drifting a bit even though it was good & warm.  I'd tune the two rigs so the received signal was the same pitch in each and 5 minutes later there'd be a noticeable difference (maybe 10 hz) as the 2B drifted away.
 
Bad:  The tone of the 2B is noticeably smoother and purer than the K2.  The K2, while it has a good S/N ratio, has a bit of a hollow tone and a bit of a raspy or bearly edgey CW tone.  The 2B is very pure sine wave.  Very mellow, very nice to listen to.
 
- Keith KD1E -
- K2 5411 -
- Drake 2B "as old as I am" -
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[Mike Harris-9]

G'day,

<quote>
Bad:  The tone of the 2B is noticeably smoother and purer than the K2.
The K2, while it has a good S/N ratio, has a bit of a hollow tone and a
bit of a raspy or bearly edgey CW tone.  The 2B is very pure sine wave.
Very mellow, very nice to listen to.
<unquote>

This has troubled me for quite a while.  Sometimes all CW sigs seem to
have a harsh tone and then you tune into another station that is a pure
note, very odd.  Also the chirpy signals seem to be a nice note, albeit
varying.  I'm beginning to wonder if there is a harsh note built into some
of the modern synth rigs.  SSB sounds OK.

The harmonic of the 4MHz oscillator up on 10M sounds OK, and is a bit of a
reality check.  However, that is a single tone, there might be some
problem with the af when a lot of signals are present within the passband.

I tend to run the af gain pretty low and have the KDSP2 installed.

Maybe someone suitably equipped could investigate the af situation.

Regards,

Mike VP8NO

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[Darrell Bellerive]

I find the same thing with my K2. I originally thought that something may be
wrong, but listening to the same CW signals on a Heathkit SW-7800 are even
worse.

I suspect that what we are hearing is simply the solid state audio section. I
could be wrong but I don't think that audiophiles are falling over themselves
trying to buy audio amps with LM380 and LM386 integrated circuits.

The fact that the odd CW signal sounds perfect is confusing. I am experiencing
the same thing.

Be interesting to pipe the audio from the detector into a HiFi tube amp.

Darrell  VA7TO  K2#5093

On August 20, 2006 01:48 pm, Mike Harris wrote:

> <quote>
> Bad:  The tone of the 2B is noticeably smoother and purer than the K2.
> The K2, while it has a good S/N ratio, has a bit of a hollow tone and a
> bit of a raspy or bearly edgey CW tone.  The 2B is very pure sine wave.
> Very mellow, very nice to listen to.
> <unquote>
>
> This has troubled me for quite a while.  Sometimes all CW sigs seem to
> have a harsh tone and then you tune into another station that is a pure
> note, very odd.  Also the chirpy signals seem to be a nice note, albeit
> varying.  I'm beginning to wonder if there is a harsh note built into some
> of the modern synth rigs.  SSB sounds OK.
>

--
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada
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[Karl Larsen]

    Guys your leaving in the speaker which makes some radios sound
terrible. Do this: Get your best earphones and plug them in and listen
to quality. My AT Sprint 3 which has good audio sounds clean and clear
on good signals like WWV when they are not modulated.

    I had a Drake 2B and it was the very first good receiver I ever
owned. Right now I will put my Yaesu FT-857D receiver up against any
comers. But with earphones not the crummy 2" speaker...hi

73 Karl




Darrell Bellerive wrote:

> I find the same thing with my K2. I originally thought that something may be
> wrong, but listening to the same CW signals on a Heathkit SW-7800 are even
> worse.
>
> I suspect that what we are hearing is simply the solid state audio section. I
> could be wrong but I don't think that audiophiles are falling over themselves
> trying to buy audio amps with LM380 and LM386 integrated circuits.
>
> The fact that the odd CW signal sounds perfect is confusing. I am experiencing
> the same thing.
>
> Be interesting to pipe the audio from the detector into a HiFi tube amp.
>
> Darrell  VA7TO  K2#5093
>
> On August 20, 2006 01:48 pm, Mike Harris wrote:
>  
>> <quote>
>> Bad:  The tone of the 2B is noticeably smoother and purer than the K2.
>> The K2, while it has a good S/N ratio, has a bit of a hollow tone and a
>> bit of a raspy or bearly edgey CW tone.  The 2B is very pure sine wave.
>> Very mellow, very nice to listen to.
>> <unquote>
>>
>> This has troubled me for quite a while.  Sometimes all CW sigs seem to
>> have a harsh tone and then you tune into another station that is a pure
>> note, very odd.  Also the chirpy signals seem to be a nice note, albeit
>> varying.  I'm beginning to wonder if there is a harsh note built into some
>> of the modern synth rigs.  SSB sounds OK.
>>
>>    
>
>  

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[Don Wilhelm-3]

Guys,

I suspect that you are hearing differences in the speaker.  My K2 sounds
good through an external audio amp with a 5 inch woofer.  It is not
audiophile quality, but then it was not intended to be.  For communications
purposes it is great, the speaker sounds smooth and due to the speaker
characteristics it reduces the high frequencies above 3.5 to 4 kHz.

Nothing wrong with solid state amplifiers - many are cleaner than tube
types.  There are audio processors available that introduce some controlled
harmonic distortion to make solid state amps sould like tube types - these
devices are available in the pro-audio field.

73,
Don W3FPR

> -----Original Message-----
>
> I suspect that what we are hearing is simply the solid state
> audio section. I
> could be wrong but I don't think that audiophiles are falling
> over themselves
> trying to buy audio amps with LM380 and LM386 integrated circuits.
>
> The fact that the odd CW signal sounds perfect is confusing. I am
> experiencing
> the same thing.
>
> Be interesting to pipe the audio from the detector into a HiFi tube amp.
>
> Darrell  VA7TO  K2#5093
>

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[Darwin, Keith]

Let me clarify.  I did my listening test under headphones - Nice hi-fi headphones.  The same ones I used in the studio when mixing my band's CD a couple of years ago.  Your right, you can't trust the sound of many rig speakers.  These headphones work well and I know them very well.
 
Tonight, the K2 sounds very, very similar to the 2B.  In fact, it sounds as good as the 2B.  Not the same, mind you, but close enough to be a complete non-issue.  What's the difference?
 
Well, I've bypassed the KAF2 in the K2.  It seems what I'm hearing may be something added by the audio filter.  With it gone, the signal is cleaner.
 
BUT BUT BUT - let me warn you.  This "raspy sound" of the K2 is small enough that you only notice it when you strain to listen for it.  In fact when I switch the AF in and out I just bearly hear the change.  It changes, but only by a small amount.  If you're just operating the rig, you'll never hear it.  After all, this isn't some cheaply made Asian rig.
 
Clearly I've gone past the realm of "reasonable" into the realm of "splitting hairs"
 
73!
 
- Keith KD1E -
- K2 5411 -
 
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[N2EY]

Various quotes about K2 audio quality:

> Bad:  The tone of the 2B is noticeably smoother and purer than the K2.

>
>  Sometimes all CW sigs seem to
> have a harsh tone and then you tune into another station that is a pure
> note, very odd.  Also the chirpy signals seem to be a nice note, albeit
> varying.  
>


There's a whole bunch of things going on.

First off, the speaker, as others have pointed out. It's a big factor, if for
no other reason than the little speaker in the K2 and the last audio stages
may be working much harder to reach the same audio level as the 2B. The only
way to approach a fair comparison is to use the same speaker for both.

Second, many humans find the kind of distortion generated by tube audio to be
less unpleasant than that generated by SS amps. Even if the tube amp creates
more distortion, it may be of a kind that is less bothersome.

Third, the oscillators in the 2B are all LC or xtal, and the filtering all
LC. This produces slightly different characteristics than the crystal filtering
and PLL oscillators of the K2.

Fourth - and I don't mean to insult anyone - but it should be remembered that
all of this is subjective. That doesn't mean it's "right" or "wrong", just
that someone may like A and not like B. Add to that the fact that any of us
making the test may be influenced by knowing which rig is which.

Fifth and last: It should be remembered that the 2B was basically an SSB
receiver. (Its immediate predecessor, the 2A, did not even have 500 Hz filtering).
The K2 is basically a CW transceiver. The basic K2 sells for just under $600,
while the basic 2B sold for a bit under $300 way back 40+ years ago. Adjust
the 2B's cost for inflation, and it's well over the cost of a fully loaded
K2/100.

73 de Jim, N2EY



Second,

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[Rick Dettinger-2]

> The K2 is basically a CW transceiver. The basic K2 sells for just under
$600,
> while the basic 2B sold for a bit under $300 way back 40+ years ago.
Adjust
> the 2B's cost for inflation, and it's well over the cost of a fully loaded
> K2/100.
>
> 73 de Jim, N2EY
 =================================================
And that is just for the receiver.
73
Rick Dettinger
K7MW

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[Darwin, Keith]

 

-----Original Message from Jim, N2EY-----
>... it should be remembered that all of this is subjective.
>That doesn't mean it's "right" or "wrong", ...

Absolutely.  Right on.  One of the things I loved about the K2, was the
clean audio.  It was one of the main factors that allowed me to sell my
very nice Omni V and replace it with a K2.  The K2 just sounded so much
better.  So not only is much of this subjective, but it all depends on
what you're comparing it against.

> ...2B sold for a bit under $300 way back 40+ years ago.
>Adjust the 2B's cost for inflation, and it's well over
>the cost of a fully loaded K2/100.

And you've hit on one of the things that is SO ABSOLUTELY AMAZING about
the K2.  It gives such fabulous performance for such a low price.  I'm
looking at a $600 transceiver that does a better job as a receiver than
a top-tier (for it's day) dedicated receiver.  And as I've compared the
K2 to other more modern rigs, the K2's prowess shines even greater.

I loaned my K2 to a friend.  He used it for a week.  Came back and his
first comment was "wow, I love that receiver".  He didn't really know
what Elecraft was.  Now he's talking about building a K2 when the winter
months come.

- Keith KD1E -
- K2 5411 -
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[Darrell Bellerive]

I don't think that the speaker that is the problem. I can hear the raspiness
on the internal speaker and several external speakers. Haven't tried
headphones, don't like them and don't have any.

The raspiness I am hearing is similar to placing an AC transformer and the K2
too close together. My K2 is at least two feet from any AC transformer and
run from an 18 Ah gelcel battery charged by a one amp A&A Engineering Smart
Charger. I do notice that the charger can increase the raspiness at times.
Switching it off reduces the raspiness. The chargers are connected to the AC
mains via a Tripp-Lite Isobar Ultra surge and EMI suppressor.

Now my raspiness is not into the realm of "splitting hairs" as it is with
Keith, it is quite noticeable. Yet it is not always there. I just tuned
across 40 meters and the CW stations sound fine now.

This same raspiness is even more noticeable on a Heathkit SW-7800 which is in
another room. This receiver has a built in AC power supply.

I am starting to wonder if I have some sort of noise on my AC power mains.
Next time the raspiness is there I am going to shut off all the breakers in
the house and see what happens.

Darrell  VA7TO  K2#5093



On August 20, 2006 05:39 pm, Darwin, Keith wrote:

> Well, I've bypassed the KAF2 in the K2.  It seems what I'm hearing may be
> something added by the audio filter.  With it gone, the signal is cleaner.
>
> BUT BUT BUT - let me warn you.  This "raspy sound" of the K2 is small
> enough that you only notice it when you strain to listen for it.  In fact
> when I switch the AF in and out I just bearly hear the change.  It changes,
> but only by a small amount.  If you're just operating the rig, you'll never
> hear it.  After all, this isn't some cheaply made Asian rig.
>
> Clearly I've gone past the realm of "reasonable" into the realm of
> "splitting hairs"
>

--
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada
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[N2EY]

In a message dated 8/21/06 8:32:01 AM Eastern Daylight Time,
[hidden email] writes:


> one of the things that is SO ABSOLUTELY AMAZING about
> the K2.  It gives such fabulous performance for such a low price.  I'm
> looking at a $600 transceiver that does a better job as a receiver than
> a top-tier (for it's day) dedicated receiver.  

With all due respect, the 2-B was not a top tier rx even in its time. It was
a very good rx, then and now, particularly for the price. (Check out how much
competing receivers cost back then).

Drake also made the R-4 family in the same time period - at a substantially
higher price.

The real Standard of Comparison among ham receivers of those days was the
Collins 75S-3. And for what they cost, they should have been!

And as I've compared the
>
> K2 to other more modern rigs, the K2's prowess shines even greater.
>
> I loaned my K2 to a friend.  He used it for a week.  Came back and his
> first comment was "wow, I love that receiver".  He didn't really know
> what Elecraft was.  Now he's talking about building a K2 when the winter
> months come.
>

Why wait?  Start one now and be ready for the fall.

73 de Jim, N2EY
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[k6dgw]

[hidden email] wrote:
> The real Standard of Comparison among ham receivers of those days was the
> Collins 75S-3. And for what they cost, they should have been!
>

Well ... YMMV, but next to each other on the same antenna, my 2B was a
significantly better CW rx, particularly in heavy QRM and/or adjacent
key clix, than my 75S3.  The mech filter sounded really good, of course,
but that 50KHz IF PBT really killed QRM.  I also had the 2BQ, which was
very smooth also, but I tended not to use it very much.  It did ring
badly at high gain settings.

Compared to the K2, I can only remember the 75S3 and 2B (they're long
gone) and my memory is a tad leaky these days, but I think in an A/B/C
test, the K2 RX would come out on top in a real, on-the-air test in SS
or IARU, possibly by a fair margin, if you've judiciously set your
filters to sensible bandwidths.

RX specs are important of course (I *am* an engineer), but the final
analysis for me was always "how well does it perform in noise, QRM, and
real band conditions.  Top-flight specs usually perform very well in the
real world.  Sometimes, circumstances just combine, and
less-than-top-flight RX engineering specs may couple with the right
combination of design features to perform extremely well.  Possibly that
might have been the 2B?

The 75S3 was a really great RX, no doubt and I wish I still had my
S-line.  eBay has Collins pointer knobs for $34.95 and the 11-pin
connectors for $15.00, but I didn't find any complete S-lines.

Fred K6DGW
Auburn CA CM98lw
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[Mike Harris-9]

G'day,

|I don't think that the speaker that is the problem. I can hear the
raspiness
| on the internal speaker and several external speakers. Haven't tried
| headphones, don't like them and don't have any.
|
| The raspiness I am hearing is similar to placing an AC transformer and
the K2
| too close together. My K2 is at least two feet from any AC transformer
and
| run from an 18 Ah gelcel battery charged by a one amp A&A Engineering
Smart
| Charger. I do notice that the charger can increase the raspiness at
times.
| Switching it off reduces the raspiness. The chargers are connected to
the AC
| mains via a Tripp-Lite Isobar Ultra surge and EMI suppressor.

This has triggered a thought.  I run my K2/100 from a Samlex SEC 1223 with
no activated transformers anywhere near it.  My Pro.Sis.Tel rotator
controller is usually turned off and I do have the VCO shield mod
installed in anticipation of some big iron (Acom 1000).  When I first put
the SEC into service I connected an HF-225 receiver to it and there was a
nasty noise on the af.  The HF-225 doesn't have anything filtering on the
12V before it hits the af amp.  On the wall wart it is fine.  It seems the
only thing between the K2 af amp and the 12V is some decoupling by R16 (10
ohms) and C28 (220 microfarad).

Maybe the SEC is pumping noise into the af amp.  Sadly I don't have a
linear PSU or suitable battery to hand at present.  I have been planning
to shift to a linear PSU 'cos the SEC kicks up a din on the LF bands every
25kHz or so.  There is a mod to the SEC to improve the noisy output
situation, must get the ferrite beads and do that.

Regards,

Mike VP8NO

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