Rerurn to Romy the Cat's Site

Analog Playback
Topic: Possibly good.

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Posted by xandcg on 04-22-2021

I've just found out about the DS Audio's Optical Catridge which on their literature looks amazing but I have no means to sanely evaluate it from the technology point of view, and so I bring to the folks smarter than me to evaluate.

DS Audio also published the circuit of the specific phono equalizer it needs, HERE.

They published some videos on You Tube:

If this is already hard to evaluate regular cartridges things get dirty when you need a purpose designed phono stage for it...


Posted by Paul S on 04-22-2021
Some version of this idea has been around for many years, never seems to get off the ground. Got to say, given the process from recording, through mastering, LP manufacturing, and playback, it's a wonder we can even recognize the original performance, as it is! Who knows how well this might be done? I haven't heard anything "serious from it yet; but what do I know?

Pretty funny hearing the usual "ticks and pops" before the music started!

Paul S

Posted by xandcg on 04-22-2021
In the first moment I thought it was another variant of the "laser turntable", but in the way it works the "ticks and pops" are supposed to be in there since they are part of the recording, in a way or another.

I believe the single great thing about this technology is removing mechanical noises related with regular cartridges.

EDIT: just reviewing my last understanding I think a specific phono stage is not really necessary but actually a SUT of sorts.

EDIT: side subject, this DS Audio's Vinyl Ionizer may be interesting given the practical design.

Posted by rowuk on 04-24-2021
We know that RIAA preemphasis is applied before the groove is cut. What is in the groove is NOT flat in response. Conventional playback regardless of MM/MC/MI needs to EQ that preemphasis out to get playback flat. The EQ has multiple corner frequencies and getting them "right" is critical.
The reason for the preemphasis was to be able to get bass in the smallest practical groove.

Now supposedly, we can playback without EQ. Where did the preemphasis "go"? How does an LDR accomplish a multi EQed signal? Want to bet that the LED dies before the stylus...

Posted by Paul S on 04-24-2021
Robin, your point is well taken, but I don't think they are trying to circumvent the laws of physics here. I did not read it yet, but Alexandre did provide a link that gets one in the vicinity of an explanation:

Clearly, this EQ system is based on the RIAA curve embedded in the LP grooves, and just as clearly it might be adapted to other recording curves.

Not saying I understand how it operates so precisely, to begin with, but I have heard that optical readers are integral parts of high speed manufacturing processes that are just as amazing, in use all day, every day, around the world.

Best regards,
Paul S

Posted by xandcg on 04-24-2021
There is a review of some UK magazine:


I found this other review that brings some more information about the construction of the cartridge. In this case, of the Grand Master one:

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