Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site eagle.UUCP
Path: utzoo!linus!decvax!bellcore!petrus!sabre!zeta!epsilon!gamma!ulysses!mhuxr!mhuxn!mhuxm!sftig!sfmag!eagle!prem
From: prem@eagle.UUCP (Swami Devanbu)
Newsgroups: net.audio
Subject: Turntables today- some impressions.
Message-ID: <1328@eagle.UUCP>
Date: Mon, 23-Sep-85 13:18:21 EDT
Article-I.D.: eagle.1328
Posted: Mon Sep 23 13:18:21 1985
Date-Received: Fri, 27-Sep-85 07:32:47 EDT
Distribution: net
Organization: AT&T Bell Laboratories, Summit, NJ
Lines: 84

*** REPLACE THIS LINE WITH YOUR MESSAGE ***

I've been looking at Turntables in the 200-350$ range (excl.
cartridge). Here's some assorted ramblings, with questions.


In a TT, you look at the suspension, the tone-arm, and the pick-up.
The function of the suspension isto de-couple structure-borne
mechanical vibrations. There seem to be two ways of doing this.
One is to use soft feet on the turntable, and make the turntable
itself a massive monolithic structure, using materials with good
vibration damping properties, such as wood, composites, ceramics,
etc. The advantage to this approach seems that it is cheaper;
the natural frequency is apparently a little higher, about 10-20 Hz;
This could supposedly cause "muddying" of base, whatever that is.
(probably intermodulation distortion). Also, the cover could
act as an acoustic pickup, and pass the signal on nicely to
the cartridge. This won't happen in the "float" approach, below.

The other approach isto float the platter, arm  altogether
on  high-compliance springs, with the resonant frequency well
below audible range (eg, 4 Hz). The rationale here is that the
resonance characterestics "clamp down" mechanical pickup 
starting way below the audible range. The disadvantage here
would be the difficulty of damping low-frequency vibrations.
Additionally, 4 Hz  is right about the range of footfalls and
dancing feet on wood floors; so this might jar the tone arm,
cause skipping etc. Its difficult to damp slow oscillations;
Now if you had a HEAVY subchasis, and had a piston attached to 
it,  in a jar of say, molasses, it would be great. I wonder
if anybody (SOTA, Oracle, Linn Sondek) goes to THIS extent.
Comments ?

I looked at 5 TT's that used a floating subchasis. The NAD 5120,
at $180, the Systemdek IIX, at ~$320, the Beogram 1800, ~$200,
The AR's, the older one at $330, and the new at $210. All 
tonearm included, except the IIX. The  most striking design
was the NAD. (also the cheapest). The specs where comparable,
as was the subjective sound quality, on cartridges in $100 range,
and response to an adhoc tap-here-and-there-on-a-blank-groove
isolation test. 

The NAD charmed me the most - a strange beauty hath it, even as
Caliban. NAD has, as always, moved in mysterous ways in this
design, their wonders (blunders?) to perfrom. The tonearm is
FLAT (!), cut out of a multilayer PC board. The signal wires are
etched therein (!), and whole arm PLUGS into a mount on the subchasis,
proving mechanical and electrial carriage. I read a rather technical
(if immodest) piece  written by the NAD designers in "AUDIO": They
claim to have tuned the flat arm's cantilever resonance to
"conduct" cartridge resonance into the (static balance) weight.
They also claim that PCboard damps oscillation on a vertical
plane very well, and is totally inflexible on a horizontal.
Not knowing much about the mechanics of arms, I humbly believe.
Overall, this TT seems best value for money. As ugly as
sin her(him?)self, but it tracks well, sounds just fine to
my Leaden ears, and resists knocks and taps as well as TT's 
costing twice as much.

Questions:

a) Has anyone heard/seen the NAD ?  What do you think ?

b) Is Subchasis isolation really better ? Then why doesn't
   everybody use that ?

c) What exactly do I get for the extra $200 in a systemdek or
   an AR ?
   
d) Are there any other tables in this price I should look 
   at  ?

e) Is there anyway of getting the best of both the "softfeet"
   and floating subchasis  designs ? (In my price range, of
   course). Perhaps graftable feet ?

f) Any recommendations for cartridges in the $100 range ?



Thank you.

Prem Devanbu,
(....eagle!prem)


Brought to you by Super Global Mega Corp .com