A-T Answer - "pF" AT-LP5X Turntable

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kfbkfb

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My Question:
“CD-4 (Quadradisc) vinyl records with quadraphonic sound require low capacitance tonearm wires, do A-T turntables have this?”

Answer:
“The combined capacitance of the tonearm wiring and the interconnect cable provided is 292 pF”
Scott from Audio-Technica


I'm considering getting a new turntable (I bought my current turntable in 1982-06), anyone found a current Audio-Technica turntable suitable for CD-4?


Kirk Bayne
 

Sonik Wiz

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Finding a current TT (how current?) is a bit dodgy because it seems like this stuff still changes more often than you would expect. I will say I have a newish (5>7 yo) AT LP-120 with an AT 440-MLB cartridge. I'm not really a CD-4 fan but when I got new I hooked up my Clarion demodulator & everything tuned up fine with a test record & I enjoyed listening to some of the old faves in CD-4. Then because I don't think the Clarion has matching quality for my main pre-amp it went back in the closet. But it worked great. I've had better luck than most with CD-4 however who knows how it would do after a few years use on the stylus?

My first impression of the AT LP-5X is it's dropped some appreciated features of previous models but has added USB, Bluetooth, and a built in MM/MC RIAA pre-amp. I am dubious about the impact on audio quality these "life style" features bring, and certainly no benefit for CD-4.

Consider a trip to Vinyl Renaissance in OP? They have some nice stuff.
 

Sonik Wiz

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Addendum: In reading an article by Harry Maynard in the Spring '84 MCS Review he detailed the requirements and advances in the CD- 4 system. Regarding phono cable capacitance 100pF is listed as the maximum level of tonearm and interconnect for best CD-4 demodulating. I just spent a bit of time after that & found other AES & the such that say the same. So the AT LP-5X is quite a bit out of range. Hey, at least you got a decent response from the company!

It has occoured to me that tonearm cap is almost negligible in this consideration. They are shielded from noise by the metal tone arm otherwise straight strand wire. Most of the capacitance I'd estimate is from the interconnect between the table and the CD-4 box. If you don't mind opening up a TT to replace the wiring, then Blue Jean Cables has an excellent choice called the LC-1 at only 12 point something pF per foot. And you can have it cut for exactly the length you need. Only downside is they want to terminate it RCA both ends but I'm sure they could do it only at one end & maybe save a few $$.

Also with all the talk of stylus types there's more to good CD-4 than just that & cables. Proper CD-4 carts had built in mechanical resonance nearly 2 octaves higher than regular stereo MM, peaking at 60kHz. This certainly helped keep the carrier signal healthy. Also there was higher separation L/R into the higher frequencies than existed with stereo carts, then and probably today.

Some high fiber food for thought...
 
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