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PostPosted: August 26th, 2016, 12:14 pm 
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I first set VTA/SRA by listening. A very tedious process and I feel very imprecise. I found the differences I was hearing very subtle. My Stylus is a Peter Ledermann retyped Alpha Genesis 1000.
The diagram in upper left is from Peter Ledermann wbsite. Upper right is stylus down on mirror with 1.75gr weight.
Lower left is showing 90 degree ref and lower right is measuring the 20 degree angle shown in the diagram
So I might be close, who the hell knows but it was fun


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PostPosted: August 26th, 2016, 1:12 pm 
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And yet -- dragging that piece of crystallized carbon along grooves containing of all things music -- with the right set-up -- that crude playback system still seems to embarrass CD or any other digital medium. :violin:

If only Alan Blumlein was alive to witness it. :obscene-drinkingcheers:

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PostPosted: August 26th, 2016, 3:14 pm 
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Aside, there is also the Blumlein line (pulse forming network). One question I have for the vinyl enthusiasts is how is the record fabricated? Is your playback technology vastly better than the technology that went into making the record? Consider that in driving the cutter there is much much more mass involved than playing back the record with all the associated problems (resonances, etc.). Also, what are the problems involved in the stamping process for making the records? Also what is the form of the master source for the record? Is it digital or are you saying you have an analog tape or a direct analog line from the microphone to mixer to record cutter?


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PostPosted: August 26th, 2016, 3:20 pm 
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brombo wrote:
Consider that in driving the cutter there is much much more mass involved than playing back the record with all the associated problems (resonances, etc.).


:character-oldtimer: When records are cut there is much more TREBLE cut into the lacquer, not bass. On playback, that treble is then cut back down in the phono stage, dropping the inherent HF noise in the playback system dramatically at the same time (which is why it's done that way in the first place).

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PostPosted: August 26th, 2016, 3:28 pm 
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Then why do most complain about the "digital" sound?


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PostPosted: August 26th, 2016, 3:37 pm 
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Pelliott321 wrote:
Then why do most complain about the "digital" sound?


Who are you asking?

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PostPosted: August 26th, 2016, 3:43 pm 
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To answer Paul -- It's bandwidth. Digital has a "stop" frequency. Stereo cutters, as a generic group can go out to 40-kHZ. or better. A Japanese study found that people could sense the increased resolution with the playback capability out to 50-kHZ. They also easily identified the poorer reproduction when the playback was bandwidth limited. I believe it has a lot to do with rise-time capability. I know that in my own experience, when I added a pair of slot-loaded JBL ring tweeters to my Altecs, I not only got better extension in terms of basic frequency response, but the add-on tweeters, to my surprise, served the mid-range reproduction in ways I didn't expect. The same goes when I compare an LP to its CD cousin -- for the most part the LP playback just seems more open -- more "see through."

And the very anal Sheffield direct-to-disc recordings what with their tube electronics and hard-wired connections -- well I haven't auditioned any CD that has that magic.

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PostPosted: August 26th, 2016, 4:07 pm 
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Has anyone heard of a DAC that uses what I call delta modulation. Essentially the circuitry connects each sample value with a piecewise linear function instead of a histogram. If you do this the filtering needed for the output is much less. The fourier transform of a gate function (a step up and a step down) is sin(w*t/tau)/(w*t/tau), (w=2*pi*f) where tau is the width of the gate (time between samples). This is what you need the high frequecy filter for in the DAC. If you have DAC that produces a piecewise linear output signal the function you have to filter is
(sin(w*t/tau)/(w*t/tau))**2 which rolls off much quicker at high frequencies so you don't need a super stop band filter at a multiple of the sampling frequency. I don't know if any ever build a DAC with a piecewise linear output waveform.


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PostPosted: August 26th, 2016, 4:13 pm 
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Here we go measuring penis length again, boring boring boring
This is why I post so rarely


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PostPosted: August 27th, 2016, 10:55 am 
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YUP! I don't drink enough beer for a pissing contest either. There are always arguments for certain digital processes. YET - - I have a friend in New York (I met him at the CAF last year) who despite his efforts with LP playback, was kind of leaning toward his SACD player in lieu of LP playback. Based on his description and list of components, it seems that he has a nice system by audiophile standards. I got frisky with him and offered to see him one of my modified cartridges. He went with one of two choices I offered for sale and now he cannot believe how good LP can be. The moral of this story is -- if one has a mediocre LP playback system I would then expect that digital is the Messiah for those people.

There -- I am out of piss. :crazy:

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