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#144587 01/03/06 10:50 PM
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cowabbi Offline OP
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Hello all.....not to bore you all as I know this subject has come up many times before however never with a vintage record player as the topic.....
Could anyone please tell me if the above player will work on 50hz after I step the power down as we have 240v here in oz.
kind regards

Joined: Aug 2002
Posts: 1,691
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To put it simply, no.

Most likely the motor on a gramophone that old is AC and is dependent on the line frequency to hold its speed (like clock motors are).

A 110 volt 60 hertz AC motor will spin slower at 50 hertz even if it's running at the same voltage.

If this were a DC motor, as is the case with modern turntables, then it wouldn't matter because the AC from the line gets dropped and then rectified into DC.

Joined: Feb 2003
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I had a turntable once that had a timing light built in. There was a screw that could adjust between 50 and 60Hz, with a little fine-tuning besides. You knew you had it properly adjusted when the little tic-marks on the rim of the turntable stayed put, rather than appear to turn slowly backwards, like wagon wheels in old Westerns.

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cowabbi Offline OP
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Hi there yes you are right it has an ac motor I can adjust the pully to get the right speed.....my worry is will it do the motor any damage and or the tube amp?

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If you can get a 6/5 bigger pulley on the motor it should work ok with a little engineering.
Check that the motor doesn't get excessive warm but its probably a shaded pole motor which should give no problems while providing a little more torque.

The tube amp runs via transformer + rectifier on DC and should be no problem as long it gets the correct voltage.
From your post I think its 110-115 Volts on its primary side?

So a 240 V / 110 V stepdown transformer ± 250 VA should work fine.

Note: check what the total VA or Watts rating is of the turntable amp + motor.

Good luck ! [Linked Image]


The product of rotation, excitation and flux produces electricty.
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Quote
not to bore you all as I know this subject has come up many times before

We never get bored with stuff like this! [Linked Image]
Welcome aboard!

Most of those shaded-pole motors on turntables were intended for use on different frequency supplies anyway. The manufacturer just shipped them with the appropriate size pulley for the intended market.

I happened to be browsing through some old service booklets for Garrard decks from the early 1950s a few nights ago (the RC75 and RC80 series for anyone familiar with them).

As well as the expected 50 and 60Hz pulleys, Garrard also provided one for 40Hz supplies. So where in the early 1950s was running on 40Hz?


[This message has been edited by pauluk (edited 01-04-2006).]

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I've got quite a few US televisions and radios and powering them here has never been an issue.
Firstly the live chassis stuff needs to be fed from an isolating transformer and not a cheaper autotransformer.
The frequency is a non issue except for synchronous motors. And then it's only in clocks, tape decks and gramophones where the slower speed is important.
I don't know the model of record player in question, but my guess is it's typical of US design throughout the 50's-60's with a shaded pole induction motor driving the turntable. The amplifier will be a live chassis design with one or two valves like 35W4 and 50EH5 or that sort of thing. It is not frequency sensitive and will in fact work on DC.I can't recall any US made portable gramophone or mantel radio with a transformer isolated supply and parallel heater valves.
With heater current being a max of 300mA (about 30W) and the motor probably drawing about 20W then a 60W transformer will do. The high tension supply for the valves won't be more than about 50mA and is scarcely signifigant in the overall current consumption.
In this situation the easiest way out is to get a 12-120V 60Hz inverter off Ebay for next to nothing and power your 60Hz appliance from that. The inverter is of course powered by a 240-12V(or 13.8V)DC supply of sufficient current rating.

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So where in the early 1950s was running on 40Hz?
Parts of Western Australia were. In these areas, the generating plant had been obtained from South Africa. Some of the radio manufacturers in Australia did make 40 cycle models. The transformers in these sets are larger than the usual 50 cycle model. WA was also the last state to standardise on 240V in the 1980's.

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Yup, my first big Dual brand record player had such a strobe light too. It made spotting the glitches in the electronic drive control fairly easy [Linked Image] Though the speed variations were audible too.

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cowabbi Offline OP
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Thanx aussie 240 u r quite right the player has a complement of 3 valves 12AV6 35W4 50C5....am I not just better off buying a good stepdown instead of an inverter, as the other kind folks have said most of these motors run on both 50 or 60hz a change of pulley was required is all...what say you
kind regards

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