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Ariston RD11 Capacitors

M

Mr Pig

^'- -'^
I'm refurbishing an Ariston RD11 and I want to replace the capacitors. The power supply is just two caps and a resistor in scotch block, same as the original LP12.

Does anyone know the values? The caps don't have any writing on them.

Thank you :0)
 
This any use @Mr Pig:
https://www.kenwoodchefrepair.co.uk/store1/Ariston-RD80-RD110-Repair-Kit-p145758649
Edit: unceremoniously nicked from Vinyl Engine:

In the library on this site is a manual that covers the RD11, the RD80 and the RD11 Superieur.

They all use the same circuit. They all have a .22 uf cap for 240v @ 50hz. They all refer to removing the 10k resistor and replacing the .22 uf cap with a .18 uf cap for 110v @ 60hz.
:)
Apparently you can also use a Linn Valhalla etc
 
According to the Kenwood link, the 10nF goes across the switch, presumably to stop switching noise. The 220nF is the phase cap and the 10k is to drop the input to the motor to 110V
As an aside, I can't quite get my head round the fact that an X2 rated safery cap is designed to fail short circuit in order to blow the fuse in the case of voltage spikes etc. If your appliance has a 13A fuse, that's a lot of joules to dissipate...
 
a.palfreyman said:
According to the Kenwood link, the 10nF goes across the switch, presumably to stop switching noise. The 220nF is the phase cap and the 10k is to drop the input to the motor to 110V
Click to expand...

So I really should just need to replace the 220nF cap then? I'll have a look in my bits box, I might have one.
 
Replace the 10k R with a min. 2W metal film resistor at the same time, while it is all apart. No reason not to.
 
martin clark said:
Replace the 10k R with a min. 2W metal film resistor at the same time, while it is all apart. No reason not to.
Click to expand...
Hi Martin, I just got a RD11s TT last week, I found that the motor and resistor were changed and now are Allied Motion 110V 50Hz motor (9904 111 31813) and 5W 6ohm 8J resistor. Does my resistor is correct to use?
Or I should go back to 10k resistor?
 
KC Cheung said:
Does my resistor is correct to use?
Click to expand...

Does it work? ;0)

I sold one of these a few weeks ago and played it against my LP12, which is forty years younger and higher spec. These old Aristons are not disgraced, they sound very good and are a bargain.

Until people read this post...
 
Mr Pig said:
Does it work? ;0)

I sold one of these a few weeks ago and played it against my LP12, which is forty years younger and higher spec. These old Aristons are not disgraced, they sound very good and are a bargain.

Until people read this post...
Click to expand...

I got this from ebay 1~2 weeks ago.
It's working but it got a slightly 'Wow' sound from the motor.
My system is on the way to my home from other country, so I can't listen it at this moment.
 
KC Cheung said:
It's working but it got a slightly 'Wow' sound from the motor.
Click to expand...

These motors are not silent. It's normal to get chuffing or scrapping sounds from them but you can't hear it through the speakers. A drop of fine oil on the top and bottom motor bushing is a very good idea, help the motor run more smoothly.

You can use an RPM speed app on your phone to check the speed. Use a roll of tape to the the phone centered on the platter to it doesn't wobble as it rotates.
 
Mr Pig said:
These motors are not silent. It's normal to get chuffing or scrapping sounds from them but you can't hear it through the speakers. A drop of fine oil on the top and bottom motor bushing is a very good idea, help the motor run more smoothly.

You can use an RPM speed app on your phone to check the speed. Use a roll of tape to the the phone centered on the platter to it doesn't wobble as it rotates.
Click to expand...

Thank you for your advise, will try to lub the motor.
I did the rpm test and it got 33.2x rpm, slightly slower than standard but I think it within the tolerance.
 
KC Cheung said:
Hi Martin, I just got a RD11s TT last week, I found that the motor and resistor were changed and now are Allied Motion 110V 50Hz motor (9904 111 31813) and 5W 6ohm 8J resistor. Does my resistor is correct to use?
Or I should go back to 10k resistor?
Click to expand...
Whomever replaced the motor went with the standard 6k8 (6800 Ohm) as suggested within the motor datasheet. This recommendation is meant to have the motor operate at circa 110V on circa 230V. Most turntable makers run resistor and/or capacitor values that take the mains down to less than 100V. Rega, for example, started out using 15k for both the UK and Europe (same value as in the early RD11/LP12 electrics pic posted by @cre009 in post #4), later changed to 12k UK and 10k Europe; these before going over to using a second 0.22uF X2 rated metal film capacitor as voltage filter in place of the power dropper resistor. Since sometime during the late 90s Rega have taken to combining capacitor and resistor as voltage dropper; with the P3 2000 PCB having 2 x capacitors and 3 x resistors on (as did the circuit included within the original 110V Planar 3 Upgrade Kit).

Reduced voltage equates to less motor vibration, that is, as long as the phase capacitor remains capable of doing a reasonable job of approaching a 90º phase shift between the feeds to each motor coil. If Allied Motion had bothered to include the 2nd page of the McLennan datasheet, the person who did this motor/resistor swap out would likely have considered the following...

"The optimum torque provided by the motor should only be sufficient to accelerate the platter to synchronous speed, since the lower the motor torque is during fixed speed operation, the lower the vibration inducing torque ripple will be.

For a given installation it may be possible to increase the value of the series resistor ( nominally 6.8 Ohms ) [Ed: should be kOhms] in the basic circuit to optimise motor performance while a lower value of the phasing capacitor ( nominally 0.22 μF ) may prove beneficial. For optimum results trimmers may be added in series with each motor coil to electrically balance the motor."​

FYI, with the anniversary Planar 25 Rega fit 0.2uF (via parallel connecting 2 x 0.1uF) as phase cap and fit 2 x 10k pots for hand trimming for lowest vibration (i.e. bare motor actually in hand whilst twiddling these pots). I'm not sure what the voltage drop is before pots with these yet, as they were well into using capacitors as voltage filters. Regardless, as P25 preceded P3 2000, I suspect that the voltages (to each phase) that delivered lowest vibration with P25 were used to determine the fixed capacitors/resistors mix for P3 2000 (and Planar 2/3 Motor Upgrade Kit).

In conclusion, a lot can be learned from looking at these various PCBs/circuits, not to mention that the old 6-way terminal block of RD11/early LP12 makes for a great test platform.
 
Last edited:
9904 111 31813 Series AC Synchronous Motors by Allied Motion (mclennan.co.uk)
Download the data sheet, agree with the above 0.2uf is the correct Phase shift cap and trimming your mains voltage down with the 6.8K resistor to reduce vibration where your mains is higher than 240VAC can be beneficial to a certain extent but have a listen as I found you start to lose some drive and pace if you go to low o_O
Any additional caps on the original Linn/ Ariston design were only spark suppression across the switch
Alan
 
That 9904-111-31813-ac-synchronous-motors-datasheet.doc wouldn't render properly in Word 365 here, plus the second page that came along with when Mclellan took over has since gone missing.

Here are pages 1 and 2 in .jpeg format. Last two paragraphs on page 2 are what I quoted in post #18 above. Perhaps the second page was simply a separate motor installation document that they decide to include at one point.

Premotec-9904-111-31813-Datasheet-pg1.jpg


Premotec-9904-111-31813-Datasheet-pg2.jpg
 
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