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1 hour ago, Chris A said:

Perhaps placing absorption on the walls next to the Jub mouth exits (a total of twelve 2' x 2' pads, mentioned above) is a more useful approach--with the Jubs back into the room corners, within 12 inches of touching the adjacent walls.

Yes. I will do this in time. Aesthetically it would be much more desirous as well.

 

1 hour ago, Chris A said:

If that absorption trick didn't work as advertised, I wouldn't recommend it.  It works very well however, and the imaging covers side wall-to-side wall (with 31 Hz cutoff as shown below):

Yes. Roger that. I have no reason to doubt what you are telling me. And no reason to not do it except time and a little money.:)

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Some of the extra effort taken in posting the above measurements and settings stems from the apparent tendency of others (not you) that mistakenly believe that Khorns and Jubs should be pulled out of their corners for home hi-fi duty (just like they do with every other loudspeaker, it seems).  That recent Stereophile review of the Khorn (...the disastrous one...) is but one of a long line of those that even had people on this forum thinking that they could pull the latest version of the Khorn out of the corners.  The effect of doing this instead of using nearfield absorption panels to control near-field early midrange reflections is something that's in the category of "I shouldn't have to say this". 

 

A link to a FAQ on setting up corner horns for best imaging performance from a few years back:

 

 

Chris

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I can say the most dramatic "mod" that I have ever done to my HiFi system(s) has been to treat my room.

Better than any tube, cable, amp... maybe with the exception of getting K402 horns. 😎 twice 😫

 

My panels are DIY, a bundle or two of Corning, several yards of Guilford of Maine and a little wood to frame everything and a way you go.

 

When I sent Chris the first (of many, and counting) sweeps from my room, he immediately knew my room was well treated based on how the REW sweeps measured.

 

Well worth the effort!

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I agree with you 1000%... I highly recommend doing room treatment to get your system sounding its best BEFORE upgrading equipment, unless you are upgrding for features or compatiblity.

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Some of the extra effort taken in posting the above measurements and settings stems from the apparent tendency of others (not you) that mistakenly believe that Khorns and Jubs should be pulled out of their corners for home hi-fi duty (just like they do with every other loudspeaker, it seems).  That recent Stereophile review of the Khorn (...the disastrous one...) is but one of a long line of those that even had people on this forum thinking that they could pull the latest version of the Khorn out of the corners.  The effect of doing this instead of using nearfield absorption panels to control near-field early midrange reflections is something that's in the category of "I shouldn't have to say this". 
 
A link to a FAQ on setting up corner horns for best imaging performance from a few years back:
 
 
Chris
Do you recommemd the same with the MEH?

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The K-402-MEH drivers/ports (dual 15" woofers) were sized to be able to use in the center position between Jubilees in room corners.  It does that job well--below measured in the center position touching the front wall, with the horn centerline elevated 46 inches above the floor level:

 

K-402-MEHwithDanley-StyleCrossoverFilters.jpg

 

Note the -3 dB roll-off at 16.5 Hz with boosting/flattening PEQs.  This is pretty spectacular performance that can eliminate the need for subwoofers in-room if a surround array of K-402-MEHs are used in a 5.0, 3.0, or 2.0 configuration.

 

But even in this instance, if the K-402-MEH was in a room corner, it picks up 10 dB of bass response below 85 Hz due to the efficiency of the horn to load the off-axis woofers in room corner loading.  So placing them in corner loading is a significant advantage in reducing modulation and phase/group delay distortion, which should be taken advantage of...if possible.

 

Chris

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On 10/18/2019 at 2:16 PM, Chris A said:

Here are the PEQs that I used for that measurement, in case you're wondering if I used some form of low frequency PEQ boost (which I didn't)...

 

1891726791_JubbassbinPEQs.thumb.JPG.08a215986011fa50a9947a58739e5f3e.JPG

 

What function does a 0.0 dB / Q = 4 .362 "filter" perform?  I wouldn't think such a filter should accomplish any phase rotation if that's what it's for...

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That last PEQ filter isn't being used. Those are the default settings for unused filters (0 gain, 1000 Hz frequency, 0.33 bandwidth).

 

You can mute the filters not being used, but I can't tell any difference in the sound.  Sometimes I mute them, but if I've been doing a lot of editing, I probably just set the gain to zero if I don't need the filter in order to save the prior filter frequency and bandwidth in the settings to remind me of what that filter was doing before my latest edits.

 

Xilica allows inputs into the filter bandwidths, but only calculates the "Q" for you and displays what it would be if it accepted "Q".

 

EDIT: The available filter types are PEQ, lo-shelf, hi-shelf, and all pass ("phase 1" and "phase 2").  If you wanted to rotate the phase, you'd use the phase1 or phase 2 filter types (which I actually never use). 

 

Chris

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I played more with the First Watt amps and found that I was able to get the F1 in particular to sound amazing - so much so that I plan to purchase it and run it as my reference amp. It turns out it is an F1J too, so I get the JFETs... nice.

 

With the Crowns on the bass and the F1J on top, I'm riveted by the 402's.

 

Only bad news is the Jub bass bins were delayed and won't be with me until end of November now... good things take time huh. 🙂

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The First Watt F1, F1J, F2, and F2J are all transconductance amplifiers--apparently the only ones ever built in SS for the consumer public (according to Nelson Pass).  A thread from a few years ago where I was attempting to gather more experiences with them:

I'd like to know how this amplifier sounds different to you relative to others.

 

Chris

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3 hours ago, Chris A said:

The First Watt F1, F1J, F2, and F2J are all transconductance amplifiers--apparently the only ones ever built in SS for the consumer public (according to Nelson Pass).  A thread from a few years ago where I was attempting to gather more experiences with them:

I'd like to know how this amplifier sounds different to you relative to others.

 

Chris

 

Hi Chris

 

I had looked into the First Watt stuff some years ago but due to an absence of units to trial, and the seemingly narrow band of system suitability for each the First Watt amplifiers, I moved away from them.  Luckily I now have two friends with different models to sample as noted above.  

 

I think I should preface the following comments by saying that I have now tried several amplifiers on the K402 section - in all cases, the amplifiers with balanced inputs from the Xilica have sounded 'more right' with less noise.  This is to be expected I guess.  Nonetheless, the personalities of all amps were easily determinable, and I have been able to adjust the PEQ settings to sound somewhat 'optimal' to my ear for each.  The sample size is not great enough to draw sweeping conclusions - but here is what I have.

 

Crown MacroTech 2400: (balanced)

MASSIVE sound stage, tall, wide and deep.  Super detailed.  Very clean sound, but almost laser-like at times on the 402's.  Icy, ruthless, not necessarily relaxing, but truly fascinating. Ultimately, whilst it is amazing to hear so much detail and sound overall, it is a bit too much - like everything is there in your face and there is no opportunity to just relax back into to the music.  This is the OCD mad scientist amplifier of the bunch.  If I had to keep it on top, I would PEQ the heat right out of it and be pretty happy. Better off though as a bass amp, I am certain.

 

Other Crown amps, Powertech, etc. (balanced)

I have three other older Crown amps also, lower down the range the Macro.  In all cases they, sound 'wooly' by comparison to the Macro - sound stage diminishes in vastness. Ok, but lacking the hyper-detail of the Macro also, therefore uninteresting.

 

Primaluna Dialogue Premium HP (unbalanced)

A great amp hitherto, but requiring huge PEQ boosts on 7000 + hz to sound anything other than rolled off and boring on the 402's through the Xilica.  Just not right at all for them.  Prosaic, unremarkable and uninteresting.  A real shift from the excellent, smooth, involving response it offered on the Altec 19's.  I tried running it in standard integrated mode and via the HT Bypass mode.  HT Bypass sounded better, but comparatively high noise floor.  Switching back to the Macro always yielded a big sigh - right, so there is all the sound back.

 

Musical Paradise MP301 MkII (unbalanced)

Neat little KT77 SET amp.  Sounded lovely in the mids, if a fraction 'bloomy'.  Sound stage and scale were diminished, but a nice clean, listenable sound. I didn't get the impression it had the guts to make the 402's really sing.  

 

First Watt F3 (unbalanced)

The F3 is tonally beautiful and presents a real ambient, involving sound through the 402's.  I really like it, and in some aspects, it is amazing.  I really loved the airiness and mystical sound that filled the room.  Sometimes I found this too much though, like some voices, instruments lacked solidity.  This was only very slight, and only when comparing it to the F1J

 

First Watt F1J  (balanced)

Totally dead quiet - black when necessary. Check out the specs on noise levels for this amp - it truly is uncanny.  You sometimes find yourself wondering what is happening, hard to describe - but when a track goes quiet you are left with this sense that something is missing - because you are used to hearing something all the time I am guessing (ie amp noise.)  This is the first spectacular aspect of this amp.  Second is it's detail.  Whilst it is not as ruthless as the Macro, there is tonnes of detail, and where the Macro beams this out to you, the F1J presents it to you to inspect and an indulge upon - each piece of detail is accompanied with all the little details that go along with it.  The Macro is grainy and unrefined by comparison.  

 

Dynamics and verve.  Now here is where it gets really interesting. comparing this 10wpc (likely +/-15 into the 16ohm drivers - yes) to 250-500wpc available from the Macro sounds like asymmetrical warfare, but the F1J cleans up. The dynamic swings this amp is capable of are nothing short of amazing. Coupled to the 402's ability to produce palpable, visceral sound, the F1J has the ability to relax you into the soft section of track and then leap out and scare the crap out of you.  Feeling the skin of a drum, plucking of a string etc - these things have such WEIGHT through the little First Watt - enough to shoot little jets of adrenaline into your body.  

 

Overall presentation is large, spaced out and ambient.  Imaging is pinpoint, vocals are 'real'.  The sound manages to be super detailed without being fatiguing, ever, and without sounding rolled off.  This amp just works so well with the 402's.  Everyone who has listened so far agrees.  It just seems to get a hold of the drivers and instruct them perfectly. 

 

Hey, its early days yet - but I am keeping the F1J and it will be the new 'amp to beat' as opportunities come up to try others.  I doubt there are many people out there that wouldn't be astounded by the combo. I realize there is a certain pointlessness to writing this stuff, and I am no expert, but I try to be accurate with describing my observations - for what they are worth.

 

 

 

 

 

 

 

 

 

 

 

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Just now, babadono said:

Yea but where do you get an F1J?

 

NOT my problem 🙂  - but DO start looking!

 

I would seriously like to to try the First Watt J2 - available new.  Why not buy one of them and report back to us babadono?

 

🙂

 

 

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@Chris A @babadono

 

F1 DIY kits are available as I understand, but the JFETs are unobtainium.  My understanding is that a new source of JFETs has sprung up and Nelson is in testing phases with these. 

 

Perhaps an F1J DIY possibility is back on the cards?  The circuits suitable for the original Semisouth JFETs are readily available - maybe they can be adapted?

 

All I can say is that if it cost you $500-1000 USD to put together one of these amps, there is not question in my mind that I would go ahead and invest the coin. 

 

 

 

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  • 3 weeks later...

It was my experience with FaitalPRO HF20AT driver (425 to ~18000 Hz) that they took lower value +/- gains in the PEQs than the K-691 drivers.  You might check the difference between the F1 and whatever other amplifier that you use, as the current feedback in the F1 will largely ignore the impedance changes with frequency of the drivers, resulting in a slightly flatter set of PEQs.

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2 hours ago, Chris A said:

It was my experience with FaitalPRO HF20AT driver (425 to ~18000 Hz) that they took lower value +/- gains in the PEQs than the K-691 drivers.  You might check the difference between the F1 and whatever other amplifier that you use, as the current feedback in the F1 will largely ignore the impedance changes with frequency of the drivers, resulting in a slightly flatter set of PEQs.

Hi Chris - your experience echos my own. The settings for the 1133's needed to be smoothed for the Faitals. 

 

I have a more resolute sound now, less smearing (not that I noticed it before) - the images are pinpoint and the stereo effect is more noticable. Soundstage widened and grew. All in all a more coherent driver, it seems. The only thing I noticed early on was slightly reduced mid dynamic 'weight' - "pah" sounds of lips and other such noises don't carry quite the same impact.

 

Early days. I left them running all night and a quick listen this morning suggest further gains.

 

I chose 8 ohm Faitals so the F1J sees a nominal 8, which I was told it "likes", but not exclusively. We will see how things develop.

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