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Well Tempered turntable motor repair

sonddek

sonddek

Trade: SUPATRAC
My Amadeus motor started buzzing, rattling and shaking. I think the bearing was worn due to my failure to oil it from time to time. It lay fallow for a year or two.

Yesterday I opened it up and had a good look around. Pear Audio's advice was to rotate the motor in its hole by 90º. This has worked perfectly and the motor is now completely silent and running beautifully.

While I had it open I ordered a spare motor on ebay. It's a £3 door-bell motor, Mabuchi RF-500TB-12560 12V. The means of mounting is beautifully simple, like all Firebaugh's designs. A 1-2mm thick sticky foam pad around the axle on the top surface of the motor attaches it to a square sheet of rubbery-plastic about 3mm thick. This square of rubber is clamped down onto the plinth surface so that the corners are gripped under a steel plate, bolted down. The motor is also surrounded by an unattached tubular sleeve of neoprene/foam, the wall being about a cm thick. This fits snugly in the plinth hole and maintains the vertical axis of the motor while transferring scant vibration to the plinth. Firebaugh is a genius of cost-effective pragmatic design - anybody could make this for a few quid. "An engineer is somebody who can do for two bob what any fool can do for a quid."

I will be using this excellent deck as my 10.5 inch Blackbird testing platform and I'm pleased to have it up and running again.

Well Tempered products perform to the highest standards and are worth the money not because of the cost or precision of the components which are used, but because of the ruthless and well-judged engineering logic applied to the inveterate problems of the turntable.
 
You could use it in a door-bell until it's needed in your deck ;-)

Looking more generally at my Well Tempered Amadeus I've reached the conclusion that it will see me to my grave however long I or Well Tempered live. What little there is to go wrong is easily repaired at home.
 
I keep thinking I should buy a new record deck just for a change, but my WT Record Player is so amazingly quiet, I couldn’t begin to more than match it at twice the price I’d get for it.
 
What crazy kind of doorbells do you people have that have rotary motors? I’ve never seen anything that isn’t either purely electronic or works something like an old GPO telephone bell-set (which is kind of closer to a relay).
 
Tony L said:
What crazy kind of doorbells do you people have that have rotary motors? I’ve never seen anything that isn’t either purely electronic or works something like an old GPO telephone bell-set (which is kind of closer to a relay).
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History has proven that the only electric doorbell innovation of the last 100 years worth having was when technology went from 'ding' to 'ding dong'. This miracle of technology involves spring loading the hammer so that when the button/current is released/interrupted it springs back, striking a metal bar chime that resonates at a different frequency to the first one.
 
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I've just had a quick listen for the first time to my Amadeus sporting a 10.5 inch Blackbird. Absolute bliss. Bass notes and cadences stay perfectly in tune in a way not common on many other belt drive decks. This is going to be a killer combination.
 
sonddek said:
I've just had a quick listen for the first time to my Amadeus sporting a 10.5 inch Blackbird. Absolute bliss. Bass notes and cadences stay perfectly in tune in a way not common on many other belt drive decks. This is going to be a killer combination.
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I came to your tonearm thread too late. I’d have had a punt. One bloke outfits have served me well…. Avondale, Mr Speaker and Len Gregory.
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Sounds like the bearing sleeve might be worn/coroded on one side, pesky belt tension.

Just imagine how it'd sound with a decent drive system.
 
My guess is that wily old Firebaugh calculated how much power was needed and chose the least motor to do the job. It certainly sounds as though pitch is very consistent. I like the way he slings the 'belt' around the outside of an oversize platter for torque. Makes more sense to me than a smaller sub-platter with an elastic belt.
 
sq225917 said:
Sounds like the bearing sleeve might be worn/coroded on one side, pesky belt tension.

Just imagine how it'd sound with a decent drive system.
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Yes, a bit of dental floss as belt is going to require quite a bit of tension, not a recipe for long term motor health.
Certainly prevent plaque buildup on that pulley though.

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Craig B said:
Yes, a bit of dental floss as belt is going to require quite a bit of tension, not a recipe for long term motor health.
Certainly prevent plaque buildup on that pulley though.

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Maybe he should have enabled the platter to move towards the motor when the motor pulls. Oh, wait, on second thoughts maybe that's not such a good idea. Or a belt without tension...? Sideways tension on the motor pulley is inevitable if you want the motor to drive the player. The tension seems no greater than in other turntable belts. Replacing a £3 motor after 20 years isn't exactly hardship either.
 
My Amadeus GTA has performed well daily since mid-2010 and, fortunately, its bearing sleeve still looks fine. Belts usually last about a year, so with about 30 left in a bag, that should see me out.
 
sonddek said:
Maybe he should have enabled the platter to move towards the motor when the motor pulls. Oh, wait, on second thoughts maybe that's not such a good idea.
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Funny enough, this is exactly what William H. Firebaugh's original bearing design required. Have a read of US4792938A 'Low-noise bearing for phonograph turntables and the like' here...

The Amadeus model brought with a redesign of the upper bearing running surfaces such that the platter did not list away from the motor when not under belt tension.
 
Craig B said:
Funny enough, this is exactly what William H. Firebaugh's original bearing design required. Have a read of US4792938A 'Low-noise bearing for phonograph turntables and the like' here...

The Amadeus model brought with a redesign of the upper bearing running surfaces such that the platter did not list away from the motor when not under belt tension.
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Yes, sorry I didn't make myself clear. I meant after the spindle has engaged with the North and West bushings, for example by attaching the bearing to a platform on springs. It was my idea of a joke.

The original Amadeus also had the disengaging bearing with oversized square bushing, as did mine. The snug triangular bushing was an upgrade. I fitted it and still have the original wobbly one somewhere. It was a bit disconcerting but I suspect the only downside might be the possibility of very slightly stretching the belt. That said, I make my own belts and don't find precise length/tension to be highly critical. Perhaps that's why I've had trouble with my motor.
 
Richard - conclusions on how Blackbird compares / contrasts against the golf ball alternative on the Amadeus.Were your suspicions correct?
 
rn82497 said:
Richard - conclusions on how Blackbird compares / contrasts against the golf ball alternative on the Amadeus.Were your suspicions correct?
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I mounted a customer's arm to test it, but it was actually a little short for the deck, so I didn't spend or have the time to put on a few old favourites and get a feel for it. This said, I've made the Amadeus/Blackbird base now, so it's only a matter of time until I make myself a Blackbird for this deck, and I'm itching to do it.

I did play a couple of tracks off Hunky Dory with a brand new VM95SH a little skew in the headshell to get vaguely correct alignment, and frankly, it sounded... ...very promising indeed.

As far as comparison with the golf ball arm, that will be for a rainy Sunday. It will certainly be easy to change the arms. I don't feel willing to judge on aural memory from many years ago - that would be speculation. I like to use identical moving magnets in the two arms and switch a stylus between them to try to isolate the contribution of the arm. Even then it's not cut and dried because of the vagaries of set up.

This all said, judging by my general experience of my SUPAs over the last year, I'm very excited to hear what they can do on a Well Tempered deck.
 
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