-edible zone-
- Review: The Retrotone TD124 Top Platter Upgrade
- Review Date: 2/15/2022
- Product website: https://www.retrotone.co.uk
- North American distribution: http://www.mockingbirddistribution.com
- Country manufactured in: UK
- Price as tested: $475.00 usd
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-- Description: It's a top (upper)
platter for the Thorens TD124 that is machined from a solid aluminum
billet (alloy 6082 T-651) to replace the fragile - often damaged, bent /
warped original pressed aluminum sheet metal unit. It features a
slightly larger diameter with thicker cross-sections for greater mass.
Its benefit is to produce a measure of flatness, concentricity and
balance not possible with the oem part.
The ad at
www.retrotone.co.uk goes on to state that this top platter weighs 975
grams where the oem pressed top platter weighs 325 grams, indicating
that the additional mass results in greater kinetic energy. ie: larger
moment of inertia at the platter rim.
Review:
From that
first production TD124 back in 1957 to this day in 2022 I envision a
history of warped, bent, and otherwise damaged TD124 upper platters.
Forty nine years after that first production TD124, my first one
(purchased December 2006 and in need of a rebuild) came to me with a
horribly bent upper platter. To make matters worse someone had tried,
and failed miserably, to straighten the thing. The material on these is
a soft and somewhat workable aluminum alloy. I don't know the specific
alloy that Thorens used, but it does allow some straightening and
unbending activity before work hardening takes over and the prospect of
metal fatigue prevents any further attempts. As it was with that oem
upper platter I was able to straighten it to the point where a normal
clutch function (no scraping noises or rubs) was possible. Although if
you watched the thing spin you could see evidence of issues of flatness
along its lower rim where the clutch arm engaged it. You could see also
a slightly rumpled and dimpled OD pass before your eyes at 33-1/3rd rpm.
A visual distraction that nags the mind.
That first TD124 I
bought had the serial number #2729. I photo-documented my processes of
rebuild with it to this site ( Link ). And part of that process included
its upper platter being straightened. Evidently that page got some
readers because in short order I found myself straightening bent upper
platters for several clients. My experience doing this work informed me
that while it was possible to straighten a bent upper platter back into
a functional condition, I was never able to eliminate all visual
evidence of warp-bend-flatness. Watch them spin and see minor amounts of
flatness deviation along the bottom rim where the clutch arm engages, or
on the OD where you might see any variety of damage-induced warbles and
bumps ----- or on the top surface where the record rests, in some cases
where a somewhat less than true up/down run-out, yet still visible,
might disturb the minds eye. Although, I must admit, I never thought to
blame this for a loss of sonic quality of one sort or another. (think
wow/flutter). But, but....good grief, here we have an expensively
produced, finely made record player marketed to wealthy audiophiles that
had this Achilles Heel type of weakness. Not if, but when you mis-handle
that upper platter it bends. And guess what; for most of them that is
exactly what has happened.
What if...you could get a top platter
for the TD124 that offered an absolute dead-nuts true spin in all axes
of motion. Concentricity and Flatness. A visually accurate and true spin
to offer peace of mind to the TD124 owner. Can you imagine that? I can
because I've seen one.
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-- Above photo: my personal sn#13943 with the Retrotone TD124 Top
Platter. Using a Herbies 3mm mat in this photo. Tonearm: Infinity Black
Widow. Cartridge: Shure M91-E with Jico SAS stylus assembly. This one
has the heavy iron flywheel (9 lb) underneath. My opinion; The Retrotone
Top Platter is a very nice and worthy addition to the setup.
Of
course I did take the time, while it was spinning at 33-1/3rd, to check
the gap between clutch arm and platter bottom, looking for any evidence
of run-out or flatness issues. None to be seen. Spin was very true. And
how refreshing to see this TD124 exhibit a true platter spin while
entertaining me with very enjoyable music that could be felt as well as
heard.
How I came to evaluate the Retrotone TD124 Top Platter:
A client of mine for whom I had mechanically restored a quite
beautiful TD124-II made contact with me with a complaint that his unit
wasn't reaching stable speed quick enough on a cold start-up. I remember
that job; sn#59805 (link to restoration page) Anyway I invited my
customer back over here and when he came with #59805 it was fitted with
a nice shiny new Retrotone TD124 Top Platter. This Retrotone top platter
had the full kit with both the Retrotone center hub as well as their
cork inter-mat. This has given me the opportunity to review all three of
those items. (note: the Retrotone inter-mat I will review in a separate
review at a slightly later date)
Meanwhile I was able to solve
the cold-start issue by replacing the "too-tight" 2nd party motor
bushings with the good oem set that showed no evidence of wear and
should not have been replaced in the first place. This corrected the
slow warm-up issue. Now, in fact this TD124 starts from cold in the most
robust manner I've seen in any E50 motor so far. The new running
clearance between shaft and bushing now measures between .0008 and
.0009". That is 8 ten-thousandths of an inch. Much finer than a human
hair. The previously installed bushings had been fitting tighter with
.0006 to .0003" running clearance. This experience has taught me that
the E50 motor works better and healthier with the larger running
clearance noted above, which, by the way, is still less than one
thousandth of an inch.
Actually I am grateful for this
experience and also that the customer has allowed me to continue work on
his very fine example of a TD124-II. So now, with a robust running
TD124, let's get back to the Retrotone TD124 Top Platter Upgrade.
After getting the E50 motor adjusted and working properly for #59805
I did spend some time evaluating this product on its owner's TD124 mkII.
This player has the 5 lb non-magnetic platter. It is the one originally
made for the TD135 and then could be adapted to fit the TD124 bearing.
The material for these platters is die-cast zinc. Some folks continue to
suggest that these are made from aluminum. Not true. They were always
die-cast zinc and Thorens never made any aluminum lower flywheels for
the TD124. Only the top platters were made in aluminum and Thorens used
sheet aluminum. The Retrotone platter is cnc machined from a solid chunk
of 6082 T-651 aluminum. (alloy info found on the Retrotone website).
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(hint: click thumbnail for full size image)
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-- All surfaces on this top platter are lathe-turned true and the workmanship is beautiful. As with the oem upper platter supplied by Thorens, the center hub is replaceable by means of three small machine screws. But the difference is that the Retrotone platter has threaded holes within its body to fit these screws while the oem Thorens hub uses an additional backing plate that contains the necessary threaded holes. Thread size is the same. Wall thickness is heavier on the Retrotone.
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note how the Retrotone supplied center hub uses internal hex screws that
fit a 2.5mm allen wrench
-- Note: Threaded hole size within the Retrotone Top Platter is M3 x
.5 just as it is with the oem Thorens center hub.
I tried the
Retrotone top platter with three different center hubs; One was supplied
by Retrotone, and one by Woodsong Audio, and also I tried the oem
Thorens hub (with the 45 pop-up) Only the Thorens hub will allow use
with a 7 inch 45 record. Figure Lp only on the Retro and Woodsong hubs.
Or, if you do play a 45 and have one of those 45 inserts, that would be
your solution.
The Retrotone center hub appears to be made of a
single piece of Nylon and is precision machined on all surfaces.
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(click for full size)
-- If I were to raise a complaint about this center hub it would be
that the center bore size fits a bit too snug over the Thorens spindle
pin. This closeness of fit, while good for concentric spin of the
platter, and no doubt for balance, proves to be a detriment while
engaging the clutch. The nylon of the hub is a bit too grippy around the
pin creating some drag that slows down the flywheel underneath enough to
present a significant slowing in the strobe window. That would by my
only complaint with this piece. Of course when you drop the platter back
down onto its friction pads the flywheel returns to normal operating
speed. Perhaps if the mfr were to open up the size of this center bore
by another .0005 inches the additional clearance would eliminate any
flywheel drag. (just a thought :- )
The oem Thorens center hub
(photo below) fits into the Retrotone top platter with no issues. The
one difference is that you don't need to use the backing plate on this
platter as you do with the Thorens upper platter. On the Thorens setup,
the threaded holes are in the backing plate. With the Retrotone, the
threaded holes are in the body of the platter and you don't use the
Thorens backing plate. When using the Thorens oem center hub, I'd
recommend using the Thorens screws because the length of them will not
protrude out the bottom end as far should you use the screws meant for
the Retrotone nylon hub. Although I tried it and there was no contact
between flywheel and bottom of screws. Anyway, clutch action with the
Thorens hub proved to operate normally with little to no indication of
slowing in the strobe window. Of course with this center hub you can use
the oem rubber mat.... or any other mat designed to fit the Thorens
center hub.
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-- Above photo: note how the screws supplied by Retrotone for its
nylon hub protrude out as far as they do when used to mount the Thorens
hub as I did. Probably, it would be a better idea to use the oem Thorens
screws when using the oem Thorens hub. They won't stick out so far.
Woodsong Audio center hub. This one is mine and I like it. Photo
below. Machined in aluminum and fitted with a bronze bushing to provide
a smooth fit over the spindle pin. This one, like the Retrotone nylon
hub lacks the 45 adapter, but does allow fitment of any mat you might
choose using the standard mat center hole size. In my experience the
Woodsong hub worked well with the clutch and did not cause any slowing
of the flywheel beneath.
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-- Above photo, Woodsong Audio center hub, in place but not yet
fastened. In the background is the Retrotone nylon hub.
For now
the owner of #59805 chose to go with the oem Thorens hub until he can
obtain another aluminum/bronze hub from Woodsong Audio.
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-- Above photo: #59805 sporting the Retrotone TD124 Top Platter, resides in a new plinth from Muldova. The Retrotone Top Platter fits a bit closer within the confines of its chassis, and a bit taller than the oem top platter, yet appears like it belongs there. The oem Thorens center hub is installed along with the oem platter mat. #59805 is original with its TP14 tonearm and dedicated armboard with cue control. The Muldova plinth had to be cut custom to clear the underneath linkage parts of the TP14 cue mechanism.
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-- Above image: 59805 with its dustcover.
-- Some final thoughts:
I am happy that I was able to evaluate
this upgrade top platter from Retrotone. It improves the player.
I took some measurements of this part and can bear witness that it
is indeed a bit larger in diameter. So were all cross sectional
thicknesses. Thicker by fractional amounts. Overall height was
fractionally higher as well. Just enough to more than double the weight
of it while still fitting within the design envelope of the original.
Very nicely done.
My experience is that it works well with both
the lighter non-mag platter as well as the heavier iron platter, adding
its additional mass to that one as well. And this added mass can be
experienced as perhaps a bit more slam and that sense of certainty when
playing music with low frequencies and / or aggressive rhythmic
components.
Visually it exhibits a very true spin with no
apparent evidence of run-out on any axis. Compare that to the typically
bent/warped sheet metal platter now seen on most TD124 players.
Absolutely true spin -that- in and of itself should be a welcome benefit
to any TD124 owner.
This definitely gets my vote of confidence.
Recommended for those who love their TD124 players.