aboulang@BBN.COM (Albert Boulanger) (12/05/90)
Reply to Kevin Kennedy, *NOT* me. Just posting for Kevin ;-).
Kevin R. Kennedy
d/b/a Kennedy Audio Laboratories
240 Barker Ave. #8
Lowell, Ma. 01850
Tel:(508)441-1010
10/90
Yep, its definitely time for another of Kevin's notorious newsletters,
this one being the fourth in an ongoing series of letters on tube high end
audio and related topics. I think that a bimonthly schedule fits my
available time fairly well and is in fact a precursor to a formalized
subscription newsletter. I will continue to make newsletters available for
as long as I have access to the net. This time I'm going to share some of
the joys of setting up a decent analog front end (?!) among other items.
This is not for the faint hearted and frankly CD's can provide a good
level of fuss free performance for those who are not inclined to tweak
things on a regular basis...
I recently acquired a Pink Triangle turntable and would like to share
some of my experiences with the table, arms, cartridges and establishing
synergy between them all. Oh, what a nightmare ..........
(Un)fortunately the Pink Triangle is no longer available here, due to
the importer's gun running operation and the resulting seizure of an
entire consignment of turntables a few years back.... Originally, they
cost about $700.00 new, but are available used for a song.... The
manufacturer still provides excellent support for current owners of their
tables. To preface my remarks I think I should provide a little background
on the Pink Triangle.
The Pink Triangle is one of those weird English turntables of
extremely doubtful reliability in that the original drive circuitry and
motor can be counted on to fail within a few short years, if not
sooner... The motor is a Matsushita FG Servo type (cheap) and the
electronics by PT are not good at all. I replaced the whole assembly with
a new one brought back from England by a friend and this is when I
discovered that the design doesn't actually operate closed loop due to
some unresolved design error. To make a long story short I beefed up the
power supply and motor drive circuitry and will eventually design a proper
servo controller for it.
Inspite of the above flaws, wow and flutter are extremely low and the
pitch stable once the motor breaks in. The table features a variant of the
old AR suspension, but is easily adjusted for different arms, weights and
platter matts. Isolation is excellent and the acrylic platter is dead and
non-resonant. Arm boards are easily exchanged. Speed change is fuss free
and electronic. Belt drive is employed along with a novel inverted ruby
center spindle bearing for platter support - this is one quiet bearing....
The original arm, a Helios Scorpio seems to leave quite a lot to be
desired, and consequently was replaced by an Ultra-craft AC-300 MKII
uni-pivot arm on a new arm board. This arm features variable arm damping
as well as interchangeable arm wands and weights allowing it to provide a
good match in terms of mass versus cartridge compliance for most
cartridges out there. VTA, tracking force, anti-skating bias and azimuth
are also easily adjusted. I have a Shure V15-RS on a low mass arm wand and
a Monster Alpha II high output moving coil cartridge on a high mass arm
wand. I prefer the Monster Alpha II to all the other cartridges in my
possession which currently also include an Ortofon LM-20 and a Denon
DL-103D.
I have spent many hours tweaking this combination (and I HATE
tweaking) and my experience as well as that of others indicate that VTA,
azimuth (stylus perpendicularity) and stylus overhang are perhaps the most
critical and difficult parameters to optomize. I cannot emphasise this
enough: ANY ARM WORTH ITS SALT MUST BE EASILY ADJUSTED FOR VTA AND AZIMUTH.
You cannot even begin to approach the state of the art in analog sound if
you don't have these features. In addition the arm must have low friction
bearings entirely free of play and chatter otherwise image specificity will
be lost. Good rigidity (stiffness) is also important so that any energy
coupled from the cartridge into the arm will be transmitted into the
subchassis rather than reflected back into the cartridge where it will
result in a loss of transparency. It also goes without saying that the arm
should not exhibit any pronounced resonances in the passband, and cartridge
choice should be such that the arm/cartridge resonance falls between 10-15
Hz to avoid problems tracking warps. A simple rule of thumb: low mass arms
need high compliance cartridges and high mass arms need low compliance
(most moving coil) cartridges. The turntable should also be leveled as
closely as possible and this should be done with a disk on the
platter as well as any record clamp you may be intending to use.
I have also learned just how long it can take for a cartridge to break
in properly and I would suggest you give it at least 30 hours of playing
time before making any judgements about the overall performance. VTA
should be adjusted periodically as the cartridge breaks in, and azimuth
should be rechecked simultaneously if you are using a unipivot arm.
I will try to make some suggestions about potential arms, turntables
and cartridges that I have found to be good or cost effective or both.
The new comer is often faced with a bewildering variety of choices, but I
do recommend allowing the dealer to install a matching arm on a table if
purchased new.
New arms from Morch (Danish), Rega (English), ET (Eminent Technologies)
Linn and SME are all good to excellent. I particularly recommend the Rega
RB-300 at approx. $300.00 and the lower cost Morch at about $400.00 for
their high levels of performance. Used arms can represent good value also
and here I recommend the Ultra-craft AC-300/400 MKII, and used versions of
all the above brands.
Linn and Ariston both offer good and complete record players for
widely disparate prices. The Ariston can be had for as little as $450.00
including a Sumiko Blue Point cartridge. AR offers the AR-ES1 for about
$400.00 without an arm (don't buy the AR arm), but for about $1700.00 the
Merrill turntable is hard to beat - infact it compares rather well to much
more expensive tables. All these tables are good bets used also, and in
addition those of you on a serious budget can purchase a used AR-XA/XB
for under $50.00, install a Merrill subchassis and the arm of your choice,
(you furnish the arm) and all for under $400.00 including a good used arm
and a new moving coil cartridge.... ( One caveat about used arms - it
would be best if the arm was demonstrated to you prior to purchase, and
do check the bearings carefully for play if not a uni-pivot type.)
Cartridges are a different matter, few used ones will provide good
long term service unless you personally know the previous owner and his
habits. (Low hour cartridges purchased for 10-25% of their original
purchase price from friends or acquantainces who are upgrading to even
more expensive cartridges are a good risk.) Cartridges I like are the
Monster Alpha Genesis 1000/2000, Alpha II high output, the Virtuoso Boron
DTI, the NEW Koetsu Rosewood Signature, the Micro Benz 3, and the real
bargain of the group - The Sumiko Blue Point costing under $100.00 and
only $85.00 with trade - in at the Audio Advisor. TEL:(800)942-0220.
USUAL DISCLAIMER: I have no connection commercial or otherwise with this
outfit....
On an unrelated subject, I have ranted about the quality of the
Chinese 12AX7A before, but recently I started testing them in various
amplifiers that were here for service and I have found that in some
applications such as in the Heath W-6A power amplifier the distortion
generated by this tube is about three times higher than a Philips
ECG 12AX7A. ( 0.7% versus 0.25% THD ) Admittedly this is a rather
small sample, but it does tend to corroborate my negative sonic experiences
with this tube in various other applications. I plan to build some test
jiggs and perform further measurements once my spectrum analyser is
refurbished...
Next time I'll relate some more experiences in my quest for improved
sound at something close to affordable prices.