John Curl's Blowtorch preamplifier part II

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Surely there must be a mechanical solution for goosing the spindle on the fly, once the proper offset is determined? Also, the initial offset measurement could probably be automated via camera/Arduino etc.

Yes, the Nakamichi TX-1000 from the early 80s. It moves the whole platter. Motors built into the platter.

The problem with automating is you need accurate rotational information. Guess what most turntables dont have :). Everything is solvable, but once you have rebuilt the drive on your turntable you might as well have picked up the real deal!
 
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I know this is old hat for many, but I'd heard about, but not read Bob Cordell's experiment with amplifier clipping and how often it can happen. CordellAudio.com - Home Entertainment Show 2007 . I was intrigued about the Rickie Lee Jones album referenced and dug a bit further and indeed there are a couple of tracks of significant DR Album details - Dynamic Range Database . So I have scored a copy to add to my test tracks. Based on the way DR is calculated it's actually more dynamic than Dafos. Curiousity piqued I searched the dynamic range database for other examples of very highly dynamic recordings both CD and vinyl.

Album list - Dynamic Range Database

Now I'm a tad cynical of some of the DR results from vinyl rips until I have a chance to do my own measurements as tics and pops might be counted, but amazingly there is actually some real music in there (at least if you like jazz). The real eye opener (if true) is 'walkin' with the shadows' on mfp! Well had to score a copy of that, if only for research purposes :).

Of course the music comes first however rubbish the recording, but interesting to find these possible gems in the mire. I need to fire up audacity to take a look . On the RLJ its the drum beats that make up the dynamics, but how much higher than std fare I have to find out.
Anyway, getting to the point. If we are talking about 'the best' in this thread, then why are there so few examples given of recordings that make the most of 'the best'. Dynamics is only one parameter, but an important one. Whilst I will listen to good music in whatever state it gets to me, it does sadden me that the quality of film soundtracks is in general far higher than the average of general music releases.
 
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Yes, the Nakamichi TX-1000 from the early 80s. It moves the whole platter. Motors built into the platter.

The problem with automating is you need accurate rotational information. Guess what most turntables dont have :). Everything is solvable, but once you have rebuilt the drive on your turntable you might as well have picked up the real deal!

I believe there's one other TT that has the auto-centering mechanism. Kenwood?

Jan
 
The reason I asked is because JC mentioned that during RMAF LP still sounded more involving an natural compared to (presumably) Demian's digital setup at Constellation. Perhaps the "app" was not good enough for JC & more refined listeners, but I would expect an app approved by 1audio and Constellation for the show to be good enough for the easier to please majority like me. Or perhaps the yet undisclosed "app" was not used during the show. Perhaps Demian has nothing to do whatsoever with Constellation's digital setup during RMAF, but an "app" producing LP's euphonics worth mentioning by 1audio certainly got my attention.
 
There was a Sharp linear tracking vertical turntable with with led/light gate/opto sensors arrangement that detected arm angle.
The smoothed error voltage controlled the worm screw drive tracking motor.

With some mechanical construction dexterity the likes of the above sensing system could be applied to the existing arm, and with the stylus temporarily placed in the leadout groove the rotation position dependent error voltage could be displayed on a centre reading moving coil meter for example.

Manual or automated fine positioning of the vinyl would complete the picture....
just something I have always wanted to do but never got around to trying, yet.

Dan.
 
... It may even have it's own 'Quantum Polluter' buil in :)

Most of us tend to assume that less distortion is better, so amplifier designer design amplifiers with low distortion and other criteria deemed important, to a point. Speaker designer also design speakers with low distortion and other criteria deemed important, to a point.
The only person correlating amplifier to speaker distortion I have read the paper of in my very limited experience is the late Eduardo de Lima of Audiopax, kindly enlighten me of others. He observed that H2 distortion of single ended amplifier somehow cancel H2 distortion produced by full range speaker used downstream (provided correct phasing) similar to distortion cancellation in tube circuits. He could very well be wrong, there could be other mechanism at play not yet well understood.
Somehow related, Nelson Pass commented :
I have built a lot of Class A amplifiers that have either 2nd or 3rd harmonic distortion but not both, and gave them to listeners and/or sent them out into the marketplace. I have received fairly consistent feedback which mostly mirrors my own observations.

When you start getting above about .1%, people can hear the difference.

Not a new observation - in the '60's Julian Hirsch (much derided for his supposed "can't hear it" stance) made a comment that he couldn't hear distortion below .1%. He is to be praised for his honesty.

Interestingly, there seems to be a consistent subjective comment about 3rd, which is that it seems to make sound a little more dynamic, the silences a little more black. 2nd harmonic is praised for warmth and/or sweetness, but I have found it to also have two qualities about apparent depth depending on the phase of the distortion, and I have commented on this elsewhere (BAF 2017 on youtube for example).

I have noticed that some audiophiles like 2nd and some like 3rd, probably for the character described above. Nobody seems to like harmonics above 2nd or 3rd, or at least won't admit to it... :p
These and some other reported observations made me curious to the lack of reference to the total sum of distortion of complete reproduction chain. With correct phasing, the so called euphonic distortion produced in amplifier may cancel speaker generated distortion with lower overall distortion as a net result. Perhaps research were done on the subject but results are undisclosed to protect sales.

I have seen comments regarding many people prefer system with more euphonic distortion instead of less distortion measured at amplifier output terminal, but none about people prefer sound with more euphonic distortion instead of less distorted sound measured at listening position .
 
Bill, what's the definition of dynamic range used by that database..?

A quick check and it didn't seem to have the HFN/RR "dynamic range of the real world" test track on it... :)

It may depend on individual records in the database, IMO. I have just ripped Quiet Nights album (Diana Krall) from vinyl (2009) to digital and checked DR by Foobar Dynamic Range Meter and got almost same results like in the database that Bill has linked here.
 
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Hi John,
However, I do prefer I to V loading for analog tape reproduce heads, as it suppresses the head resonance, and extends the playback response.
No. The high frequency range for a tape deck of any kind depends on resonating the head inductance to extend the frequency response upwards and to keep the response more "flat". Without this, the head will never perform to expectations.

-Chris
 
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The reason I asked is because JC mentioned that during RMAF LP still sounded more involving an natural compared to (presumably) Demian's digital setup at Constellation. Perhaps the "app" was not good enough for JC & more refined listeners, but I would expect an app approved by 1audio and Constellation for the show to be good enough for the easier to please majority like me. Or perhaps the yet undisclosed "app" was not used during the show. Perhaps Demian has nothing to do whatsoever with Constellation's digital setup during RMAF, but an "app" producing LP's euphonics worth mentioning by 1audio certainly got my attention.

I don't know about apps but you can buy probably dozens of plug-ins for vinyl emulation. Izotope has one that apparently "Simulate the dust, scratches, warp, and mechanical noise reminiscent of yesteryear for FREE with Viny".

There's even one that claims to emulate the exact process as done at the legendary Abby Road studios: "You can now add true vinyl warmth to your tracks with the Vinyl plugin, a precise model of the entire vinyl cutting, mastering and playback process at the legendary Abbey Road Studios. Learn more: https://www.waves.com/vinyl".

But Google will give you lots more.
You can easily have the ease of use of digital with the sound of analog.

Jan
 
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It may depend on individual records in the database, IMO. I have just ripped Quiet Nights album (Diana Krall) from vinyl (2009) to digital and checked DR by Foobar Dynamic Range Meter and got almost same results like in the database that Bill has linked here.

The only ref I found in the foobar docs suggested it was a peak to average ratio, which is an odd definition of DR.

DR (or Dynamic Range) is a term for the degree of dynamic variation within a piece of music or album. Low values (e.g. DR3) reflect a high abuse of compression. Tracks that are DR3 have a range of three decibels between the average and peak program signal. ... (source: pleasurizemusic.com)
 
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