Laser Turntable!! Likely at the Battle of the Titans!

[Mallette]

I was at my training center today getting our server back on the network with generator power and I met a contractor to my company I'd not met before. We had a lot of time to chat whilst waiting on the guys to get some gin in the generator and I eventually found he has one of the laser turntables. I've wanted to hear one for years. He says he'd be happy to bring it to the October 3rd Frazier Eleven/Klipschorn listening session. He got it from a friend with "more money than sense" for 200.00.

Dave

[Cornwalled]

Dave,

Good luck with it, hope you get to hear it. I haven't heard one personally, only read a review, stating that it tended to distort easy. I think it was because it had a tough time with less than perfect records. At any rate, I'll be curious to hear what you think. It's fortunate that your friend didn't pay much for it. As I remember, those were quite expensive new.

-Jon

[Marvel]

He got it from a friend with "more money than sense" for 200.00.

Wow! Talk about getting something for a song. That is incredible.

Bruce

[oldtimer]

I have always been curious about those too.

[Mallette]

For those not familiar, here is a link to the laser turntable site. This guy is not an audiophile. We did not really discuss his tastes but I suspect he is into rocknroll, etc enough to have bought and used the thing. My probes about selling it to me didn't seem to get anywhere...

He echoed both what I suspected and had heard. It plays every scratch, dust particle, etc. plus the music. Why, given the cost of entry being so high anyway, they did not include digital impulse noise reduction I cannot understand. Theroretically, there is no better way to play an LP, but obviously the head cannot discriminate. However, if you had a 1 bit, 2.8mhz DAC in there and impulse noise reduction, perhaps even dynamic range restoration ala DBX and such you could have a trully extraordinary 21rst century phonograph.

I rather suspect that little further development has taken place over the past decade or so and it's changed hands several time. However, they do seem to keep trickling them out.

I am really looking forward to hearing how it fares with pristine high end discs. THAT will tell the tale of whether the technology is mature or not.

Dave

[doctorcilantro]

I've read about this before. It's interesting. Trying to figure out what this unit outputs....analog or digital? If you could use this system with no RIAA and run it into a nice ADC, then apply RIAA and digital impulse filters....wow. I'll bet the fact that it picks up all the "noise" from dirt etc. might actually let the noise reduction work even accurately.

Found more info:

Output
Standard: Line Output (300mV = 0.3V)
Note: Phono output can be ordered if preferred
Phono output level: 3.2mV rms 5cm/sec 1kHz Lateral = MMLevel

They now sell a declicker with the new units (optional). Combining this table's mechanism with digital RIAA, in theory, is simply unsurpassable in terms of fidelity.

Does this guy have the calibration disc?

"A special calibration LP record is furnished with each Laser
Turntable and is used to set up the optics and microprocessor. The
record has about 20 minutes of grooves with no sound. It is necessary
to run this special disk for about 30 seconds.

The calibration disk should be used when you operate the
machine for the first time. Every few months you may elect to run the
calibration disk to maintain tracking accuracy, particularly if you
notice any mis-tracking during playback. When the machine is moved to
another location, it is wise to run the calibration disk again."

DC

[Mallette]

Analog. My opinion is as I stated earlier...a real 21rst century design would have it digitize and have recognition circuits for non-music noise. This thing was started many years ago at the dawn of the CD era.

Dave

[doctorcilantro]

I think the new models have coax/toslink onboard.



I'd like to now what kind of ADC is onboard now.



Either way, getting an older unit, modding it a bit, and pumping that
output into a linear gain pre > ADC > PC for realtime
noiser eduction and RIAA would be insane, VERY 21st century [].



DC

[doctorcilantro]

No digital onboard.

"Just saw this, "Digital S/PDIF coax or optical (TOSLINK) outputs
connect directly to computer or DAT Sample Rate: 44.1 kHz or 88.2 kHz,
user selectable Word length: 24-bit Size: Approx. 220 x 44 x 150 mm
(8.7 x 1.7 x 5.9 inches) ".

That is the declicker specs. The declicker converts the analog signal to digital out and analog out in the digital domain.

The manual doesn't tell you much of how it works inside."

Save 2K and use ADC/sound card of your choice & preamp.

DC

[Mallette]

Doc, not quite sure what you are referring to, though it sounds interesting. Are you referring to the ELP or something else?

Here are a few interesting tidbits from their FAQ:

Q: Does the LT digitize the audio signal from the record?
A: There is no digitization. The LT maintains a constant analog audio signal.

[JJkizak]

Sounds to me like this gadget has possibilities if the de clicker does what it says. The Soundforge software would really work well here on the fly.

JJK

[Mallette]

Sounds to me like this gadget has possibilities if the de clicker does what it says. The Soundforge software would really work well here on the fly.

JJK

I keep seeing this pop up. I have seen nothing regarding any declicker involved with this turntable. Where are you seeing this?

Dave

[doctorcilantro]

http://www.audiogon.com/cgi-bin/cls.pl?anlgtabl&1226371232&/Elp-Laser-Turntable-+-Declicke

The fact is, we now have the abiltiy to avoid the constrictions of hardware and use the software declicker of choice, in realtime. I'm really excited about the possabilites here. I have utilized digital RIAA (sorry for rambling previously w/o any full explanation), and I also implement a Butterworth rumble filter when playing vinyl. All of this is done on a computer, monitoring via ASIO, with a VST RIAA filter and any noisereduction filters deemed neccesary.

BTW - the ELP declicker is also an ADC with both Toslink and Coax outputs. Maybe it's actually pretty good? I doubt it adds RIAA after ADC conversion (prob. before?) but who knows....

Reports of problems with transients abound with these tables. In complex passages, things "fall apart". Hopefully you can grab as much info as possible off the unit so we can get an idea of it's particulars.

My earlier point was that if thsi unit's major issues, in the past, were due to the gain circuitry, and not the fundamental process of extrapolating the groove's data (i.e. the laser mechanism is the bomb), then combining a newer/refined model or modded model could provided unheard of vinyl playback fidelity if it were combined with digital RIAA implementation. Exciting stuff, but who knows....

I, for one, love my analog rig. True, it takes time to setup, and align azimuth and overhang etc. but man, it would be real interesting it this ELP lived up to its name. I really wonder how it would sound through some light software declicking which seems to be one of the major objections. People are playing these things through analog phono stages, and raving about the high end clarity, which is typically a benefit of using digital RIAA; the two in conjuction could prove unbeatable and deliciously enlightening. Yes, I'm dreaming....time for bed.

DC

[Mallette]

Ouch. 2800.00? I'll live with it or declick after the fact in the digital realm. DC, I am still having a bit of trouble following your signal path though I am assuming you are basically doing what this thing does by routing your phono output through your computer in real time. I do not understand the digital RIAA, either how it works or why one would want to do this. However, I the realtime declicking is a thought. I could implement this but had never thought of it. Might be fun, though I think I would likely stay in the analog realm for realtime listening as the vast majority of my discs do not have what I consider significant noise issues. Further, I like to "tweak" the software for optimum results which is much easier from a previously digitized disc that from realtime.

Dave

[doctorcilantro]

The fllowing is from the PureVinyl FAQ: http://www.channld.com/pure-vinyl_support_faq.html

I don't use a MAC so I use a VST plugin on a PC.

"I've read on
the Internet that by using a software RIAA equalization / correction
system such as yours, I throw away 6 or 7 bits resolution of
my audio interface! Is that true?

That's incorrect, and
is a misconception based on a simplified view of the software-based
RIAA correction process.

This subject was the
focus of a technical "white paper"
(click to download) presented at the October, 2007 123rd Audio
Engineering Society Convention in New York. The
slides (aes123slides.pdf) from the presentation also are
available for download.

The paper (#P4-6, Filter Reconstruction and Program Material
Characteristics Mitigating Word Length Loss in Digital Signal
Processing-Based Compensation Curves Used for Playback of Analog
Recordings, http://www.aes.org/events/123/papers/session.cfm?code=P4)
proves that software-based correction doesn't compromise audio
quality.

Briefly, the low-pass
characteristic of the software RIAA correction filter functions
the same as the low-pass reconstruction filter used in playback
of DSD digital audio ("Super Audio CD"), where a high
sample rate, one-bit stream is low-pass filtered, restoring the
effective digital word length (resolution).

With software-based RIAA
correction, music will typically encounter between zero (none)
to one bit of word length loss in the bass, which is insignificant
in comparison to the 24 bit word length of modern, high resolution
digital audio, and in a frequency range where human hearing is
at its least sensitive.

In fact, converting the
amplified vinyl signal with the treble emphasis intact, followed
by applying the correction curve in software enhances the
available digital resolution in the midrange and treble,
where human hearing is at its most sensitive, compared to digital
conversion after RIAA correction. Pure Vinyl performs
all internal signal processing at 64 bit resolution, which preserves
the benefit of using the pre-emphasized signal (and, as a bonus,
no distortion is added). Openness, clarity and definition in
the midrange and treble are improved, compared to doing a digital
conversion after the signal has been corrected with a conventional
phono preamplifier. More importantly, Pure Vinyl users have reported
that combining software RIAA correction with a high resolution
(24 bit / 192 kHz) audio interface (and a quality gain stage)
even provides noticeably improved "live" vinyl playback,
compared to a conventional phonograph preamplifier, confirming
our own experience.

High resolution digital
conversion coupled with software RIAA equalization represents
the wave of the future. This wave is inevitable, whether it's
from Channel D or someone else. If you're "into vinyl,"
and choose not to go this way, you're really missing
out on superior sound."

This app is very well designed from what I have heard from a very knowledgable software engineer. I have never used this particular appbut the results I'm hearing are nice. I'll post some comparision files soon. I'd love to get my hands on an ELP to see what if can do.

D C

[Mallette]

Okies, Doc. Not sure I learned much from the quote, but I read your system at the bottom and that made sense. Very interesting. Never gave that type of chain any thought and was totally unaware of any software RIAA. I DO have an old Stanton preamp somewhere that can be switched from RIAA to flat. Love to hear it! I am certainly open to new tech, though it's hard to imagine much better vinyl playback than what I get already (though I AM sort of jonesin' for a new cartridge). Until I learn more I will like continue to digitize to 1 bit, 2.8mhz and process from there.

Dave

[doctorcilantro]

Give that Stanton a whirl. Maybe run it into your DSD recorder flat and you could try RIAA with a demo of Diamond Cut 7 for PC or Purevinyl for Mac.Diamond Cut has a "virtual phono preamp" and as you probably know they have quite a bit of noise reduction experience (presets).

I'm using a VST plugin but there is also a freeware version (last page newest update): http://www.head-fi.org/forums/f46/software-based-riaa-eq-part-2-a-311909/

DC