The Arm
ARTHUR...@mpa15ab.mv-oc.unisys.com
about Sumiko's "The Arm" and whether it was worthy of the apparent deification
from his dealer.
I don't remember much about this unit, but would assert that it was NOT the
standard of excellence in the time frame during which the dealer is claiming it
was the ne plus ultra of arms. Without question, the arm to own in the late
70's was the Infinity "Black Widow", which still pops up on the used market
once in a while; the Fidelity Research was another hot item at this time.
I was still using a Rabco SL8E arm in 1979- a weird, linear, mechanical
nightmare that would be considered rather primitive by today's standards.
Art
Arthur L. Shapiro Art...@mpa15c.mv-oc.unisys.com
Software Engineering
Unisys Corporation Speaking as a civilian, rather than for
Mission Viejo, CA Unisys, unless this box is checked: [ ]
Chris Malcolm
>Without question, the arm to own in the late
>70's was the Infinity "Black Widow", which still pops up on the used market
>once in a while; the Fidelity Research was another hot item at this time.
And the "Audio Design". Not many were made, and the company fell apart
due to internal quarrels, but the design was (and is) an excellent
no-compromise design. A unipivot with a minute ballrace, damped
counterweighting, mercury bath lead-outs, and the pivot heavily damped
with silicone to provide rigidity at audio frequencies while
permitting very free tracking. At the time it was considered one of
the few arms which could make a Decca cartridge work properly.
--
Chris Malcolm c...@uk.ac.ed.aifh +44 (0)31 650 3085
Department of Artificial Intelligence, Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK DoD #205
"The mind reigns, but does not govern" -- Paul Valery
Chris Malcolm
>In article <3860j6$j...@tolstoy.lerc.nasa.gov>,
>Chris Malcolm <c...@castle.ed.ac.uk> wrote:
>>And the "Audio Design".
>Actually, it was the "Audio and Design", or A&D arm.
>>Not many were made, and the company fell apart
>>due to internal quarrels, but the design was (and is) an excellent
>>no-compromise design.
>Later taken over by Kieth Monks Ltd.
>>A unipivot with a minute ballrace, damped
>>counterweighting, mercury bath lead-outs, and the pivot heavily damped
>>with silicone to provide rigidity at audio frequencies while
>>permitting very free tracking. At the time it was considered one of
>>the few arms which could make a Decca cartridge work properly.
>Actually, it suffered from quite a few real compromises. Most notable was
>the fact that the antiskating force was fixed. It was about right for
>normal ellipticals traking in the realm of 1.5 grams, but the Decca at 3
>grams, it was to low.
It was easy to adapt an SME anti-skating weight and pulley, or to
contrive your own. Many did just this in order to run Deccas at the
lowest tracking weight. But that is notr the whole story -- the
designer believed (correctly, IMHO) that the correct anti-skating bias
was not as important as conventionally believed. I'll explain this
later.
>Secondly was the fact that it was basically unstable in one plane. While
>the arm could be balanced dynamically in the lateral axis (setting
>tracking force) it could not by in the longitdunal axis, because the
>force vector for the skating force, the force vecotr for the antiskating
>force and the pivot did not coincide, and that could lead to the arm
>leaning over.
In the version of the arm I had (A&D) this was easily and simply
correctable by twisting the main counterweight to one side. Its
mounting axis was offset for this purpose.
>Third was the mercury. Gawd, that mercury. In the later implementation of
>the arm, they simply got it wrong, and stupidly so. The antiskating force
>was generated magnetically. Two of the contact/signal pins were magnetic,
>two were non-magnetic. A magnet was placed in the base in such a way that
>the attraction between it and the two magnetic pins produced a torque.
>That was the antiskating force.
>In the early implementations, two pins were ordinary steel, two were
>stainless steel. That worked okay, save for the whetting difficulties
>with the stainless steel and the difficulty attaching leadout wires. In
>later implementation (comprising the bulk of the arms produced), the two
>stainless steel pins were replaced with brass. Further ALL the pins at
>the bottom of the mercury wells were brass.
>Unfortunately, the genius that dreamt THAT scheme up failed to note the
>fact that the copper in the brass was slightly soluble in mercury.
>An interesting arm, certainly. It was THE only arm that could track an ADC
>XLM, a low mass, very high-compliance cartridge. A no-compromise design?
>Hardly. The product's failure had little to do with the companies internal
>problems. It's failure was due to extreme difficulty (and, indeed,
>impossibility) in setting it up,
I found mine (the original A&D) as easy to set up as an SME.
>and keeping it that way,
and it stayed set up without problems. I would check it now & then, by
measurement using a special stylus-forces "weighing machine" of my own
manufacture, and by ear on some special difficult test tracks, and
never found it needed adjustment.
I discovered that the anti-skating force was (not surprisingly) a
function of both the tracking weight AND the effective groove
friction, and that this depended (not surprisingly) strongly on the
type and degree of groove modulation. Thus, contrary to the accepted
wisdom of the time, according to which many would set up their
anti-skating on flat record space provided on test records for the
purpose, the optimum was to set it up for the worst tracking case,
usually a combination of fierce transients with heavy low frequency.
If the anti-skating was set up very carefully in this way, it was
possible to run with no audible distress at lower than orthodox
tracking weights.
Many spent ages finically iterating down to the lowest tracking weight
under the mistaken belief that this reduced record wear. They were
correct in the sense that anti-skating bias reflected effective groove
friction due to the stylus forces required to follow the modulation,
so that a lighter tracking kind of cartridge was likely to wear
records less than a heavier; but with any given cartridge, the wear
was set by its compliance and dynamic properties, and these were not
altered by the tracking weight. So although a low-tracking cartridge
was more virtuous than a higher, for any given cartridge optimising
the settings for lowest tracking weight was of no real benefit.
Indeed, slightly too low a tracking weight would cause more wear.
Anti-kating bias was the wrong name for it, since in order to keep the
stylus force equally distributed between the groove sides under heavy
modulation -- the real problem -- required a lot more bias than pure
anti-skating demanded.
Thus (as the A&D designer knew) many people spent a lot of trouble
setting the wrong anti-skating bias, under the impression that they
were getting lowered wear due to lower tracking weight. In physical
fact just racking up the tracking weight until the stylus tracked
everything was good enough.
>and its horrific
>unreliability.
I'm still using mine, and it is still performing flawlessly, some 25
years after purchase. It is the second oldest component in my set-up,
and IMHO the least likely to improve the sound if I upgraded it.
>Given the change in design, every single one of the arms
>was gauranteed to fail within the terms of the warranty period.
Yes, well that was the silly Keith Monks "version".
>Good ideas, some of them. Dismal implementation, through and through.
Many years after buying it, I accidentally met the designer, Geoffrey
Sturman, working at the time as a line printer engineer for ICL. He
told me that his business partner, the man with the financial and
business acumen, had deliberately bankrupted the company and
resurrected it as a way of detaching Geoffrey from the product and any
proceeds thereof. The problems occurred because this money man didn't
understand the hifi or the design, and made a total mess of "revising"
it to produce the absurd Keith Monks version. The changes were purely
in the interests of cheaper manufacture. Geoffrey was very bitter
about it.
The very heavily damped pivot did produce a cleaner more solid and
extended bass when compared to other arms of the time, and I suspected
this extra clarity and punch extended into the lower mid-range. The
Decca was a special case in that it had such a low compliance (high
stiffness) that it set up obviously disturbing diluting resonances of
many kinds in other arms.
I'm still happily using mine with my Decca cart for playing LPs. I
expect I'll still be using it without problems for another few
decades.
Thanks for refreshing my memory, Richard, but note that your comments
largely apply to the silly KM version of this arm, which was an
attempt to make a fast buck by selling a cheaper version at a higher
price to capitalise on the well-deserved good reputation of the
original.
har...@d012s644.mch.sni.de
to it with Linn Karma (with Shibata tip) and with Denon 103. We found it
very revealing with great amount of space and very good dynamics, but we
also found some flaws: there is a ringing in the treble similiar to
old-fashioned CD players and there is a lack of stability in the bass which
you can get from a SME3012II or from a Linn Ekos otherwise.
I did not like it, as I want to listen to music not that super-analytical
way. My favourite arm is still the Sumiko "The Arm" which is very revealing
too, but with smooth to silky treble and stable bass and space projection too.
bye,
hartmut.
Richard D Pierce
>>70's was the Infinity "Black Widow", which still pops up on the used market
>>once in a while; the Fidelity Research was another hot item at this time.
>
>And the "Audio Design".
Actually, it was the "Audio and Design", or A&D arm.
>Not many were made, and the company fell apart
>due to internal quarrels, but the design was (and is) an excellent
>no-compromise design.
Later taken over by Kieth Monks Ltd.
>A unipivot with a minute ballrace, damped
>counterweighting, mercury bath lead-outs, and the pivot heavily damped
>with silicone to provide rigidity at audio frequencies while
>permitting very free tracking. At the time it was considered one of
>the few arms which could make a Decca cartridge work properly.
Actually, it suffered from quite a few real compromises. Most notable was
the fact that the antiskating force was fixed. It was about right for
normal ellipticals traking in the realm of 1.5 grams, but the Decca at 3
grams, it was to low.
Secondly was the fact that it was basically unstable in one plane. While
the arm could be balanced dynamically in the lateral axis (setting
tracking force) it could not by in the longitdunal axis, because the
force vector for the skating force, the force vecotr for the antiskating
force and the pivot did not coincide, and that could lead to the arm
leaning over.
Third was the mercury. Gawd, that mercury. In the later implementation of
the arm, they simply got it wrong, and stupidly so. The antiskating force
was generated magnetically. Two of the contact/signal pins were magnetic,
two were non-magnetic. A magnet was placed in the base in such a way that
the attraction between it and the two magnetic pins produced a torque.
That was the antiskating force.
In the early implementations, two pins were ordinary steel, two were
stainless steel. That worked okay, save for the whetting difficulties
with the stainless steel and the difficulty attaching leadout wires. In
later implementation (comprising the bulk of the arms produced), the two
stainless steel pins were replaced with brass. Further ALL the pins at
the bottom of the mercury wells were brass.
Unfortunately, the genius that dreamt THAT scheme up failed to note the
fact that the copper in the brass was slightly soluble in mercury. After
6 months or a years or whatever, the user would suddenly find his
turntable no lnger produced sound, and he would find two of the four pins
from the tone arm itself were simply gone. Worse, they would suddenly be
chasing little balls of mercury all over the place as the pins at the
bottoms of the cups disappeared and all the mercury drained out of the
cups. Pity the poor guy whose amp was sitting on the shelf below!
An interesting arm, certainly. It was THE only arm that could track an ADC
XLM, a low mass, very high-compliance cartridge. A no-compromise design?
Hardly. The product's failure had little to do with the companies internal
problems. It's failure was due to extreme difficulty (and, indeed,
impossibility) in setting it up, and keeping it that way, and its horrific
unreliability. Given the change in design, every single one of the arms
was gauranteed to fail within the terms of the warranty period.
Good ideas, some of them. Dismal implementation, through and through.
--
| Dick Pierce |
| Loudspeaker and Software Consulting |
| 17 Sartelle Street Pepperell, MA 01463 |
| (508) 433-9183 (Voice and FAX) |
Elton Toma
The listing in the recent Audio is pretty short, while older back issues
I've seen (70's) are a couple of pages long. Only problem is that only
the names are listed, not how good they are or if they worked well. So,
thanks for the history on the Keith Monks (bad) version of a good design,
but what else was really good back then?
Of course there is the SME II or III, and other names that sound
familiar are the Stax UA-7, Mission 774 and Infinity Black Widow.
Any other good ones out there?
Elton Toma
Herman
<to...@conn.ME.QueensU.CA> wrote:
> What other notable arms were out in the 70's and early 80's?
Well, I've got a Zeta that I quite like on an LP12. I was told that it
drove Linn to revise their arms. I suspect that it would rate somewhere
below the ARO or Ekos but still well above arms in the Rega category.
I would be curious to hear from someone who has compared it to other good
arms as I have only had the experience of comparing it to lesser arms in my
system.
Herman
Rod Schiffman
My brother had a pair of Grace tonearms matched to a Grace cartridge and a JVC X-1. One
arm was damped and one was not damped. He mounted them both on the same table. I
believe that they were considered the way to go when you couldn't go all out for the
Dynavector arm. I don't remember the model numbers. I believe that Grace was the
forerunner of Sumiko wasn't it.
-- Rod Schiffman
Ying Tat Leung
SMEs, Mission, and Infinity Black Widow:
Fidelity Research
Syrinx
SAEC
Was the Black Widow regarded to be the state-of-the-art then?
Regards,
Ying
-Rex, Robert S.
>familiar are the Stax UA-7, Mission 774 and Infinity Black Widow.
>Any other good ones out there?
>
also had a series of unipivot designs- one even used a wood arm. Also
Fidelity Research- their 64 and 66 were very good. Alphason brought out
their 1000 in the early 80's. How about Linn? Their original arm (model
escapes me right now) was quite good. Breuer made an excellent arm.
On the esoteric front consider the Souther and at a later date the
original Eminent Technology. Both Pioneer and JVC actually made a pretty
good arm around this time too.
For more info on some of these arms consult ( and boy am I shuddering
when I mention this) the first volumes of The Audio Critic.
Hope this helps
Bob Rex
Jem Hayward
UK perspective......
In the late 70's the SME lightweight arm and Shure V15 was finally
overtaken by the advent of the low output moving coil. The "best" at the
time was the Grace 707 and Supex 900. The Grace wooden arm was never
found in UK but was reckoned to be good. The Sumiko was also rare, but
considered similar to G707 but more expensive. Local favourites at about
the same time were the Hadcock unipivot and the Lustre arm from Japan in
the Acos version or the simpler, but better Rega version. The ill fated
Keith Monks Arm with mercury contacts was a bit of an also ran... Next
steps forward were the Syrinx which may have been the first super rigid
UK arm and then the Linn Ittok. The latter was a major success with the
Linn range of supex based cartridges. Alphason and Helius (later Audio
Note) also tried, and we should never forget the Decca International
Unipivot and Decca London cartridge. The Swiss Brueur arm was also well
respected but rarely seen. There was a UK made "Black Ittok" by Linn
that never got past the dealers own homes, followed by the Ekos (The
black coloured ittok was not the same, though the Ittok did improve over
the years). The Black Widow by infinity was useful for those who stayed
with MM cartridges, and the Mission 774 was clever and innovative and
reputedly underrated. The Fidelity Research FR64 was supposed to be
excellent, but was troublesome on the Linn LP12 due to weight and no-one
used anything else in those days. The Mission Mechanic, and Zeta arms
were alternatives. The Naim ARO has been discussed and IMHO is the best
on offer, but for heavier decks the revamped SME range are good. The
Well Tempered arm design may well be based on a design in a UK Hi Fi
magazine using a arm tube suspended on nylon threads with massive
silicone damping - clever, but no-one in those days really understood
rigidity at AF. Today, there are a lot of interesting designs such as
the Wilson Benesch, the Graham, the Morch, and recently a beautiful
parallel tracker from Nottingham Analogue. This thing doesn't have to
sound good, no-one with an ounce of engineering emotion could fail to
want to possess one, pity it wont fit my Linn......
Jeff Davis
arms:
Dynavector 505 - strange displaced bearing design
available in grey, blue or red.
The "wooden" Grace was the G714. It featured a
teak or teak-like tapered rectangular
armtube and no silicon damping at its unipivot
bearing. It was also available with anodized
aluminum (aloo mini yum for you Brits ;-)
armtube as the G704.
Mayware's Formula Four was popular in the late
seventies. Similar to the Hadcock, it
was a silicon damped unipivot. It was
cheap and cosmetically attractive.
Magnepan arm c.1980 was a naturally damped
unipivot that featured a thrust-ball-in-race
style unipivot versus the more common
point-in-cone type. A clever and robust
design that is still in use in many places.
This may have been the first arm to use
carbon fiber components.
Transcriptor's Vestigial which as its name implies
was just a gossamer of a pick-up holder.
Its vertical bearing was located 1.5cm
to the rear of the stylus with a Goldbergian
thread routed to the counterweight at the rear