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

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.

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.

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?

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 !

We never get bored with stuff like this!
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).]

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.

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.

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 Though the speed variations were audible too.

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

The biggest problem with frequency changes on most of these old units will be finding a source for the correct pulley, unless you happen to have machine-shop facilities to make one, of course.


Not the Dual 505 by any chance?


Ah, with the Commonwealth as it was in those days, I expect that was Garrard's main intended market for 40Hz versions then. By the way, I've always been something of a lover of Garrard turntables. Were they very common down under?




[This message has been edited by pauluk (edited 01-05-2006).]

Hey Pauluk
the most common everyday turntables were BSR all major manufacturers used to use their various models however garrard was deemed in the 60s at least to be superior and therefore were used in more expensive machines. They had a laboratory series which claimed to have a much more stable motor and also a bigger idler wheel so as to reduce wow , flutter ,etc these units were more expensive than most others and were called the audiophile series.
In the very late 60s and early 70s the duals from germany became the favourite with most local hi fi manufacturers

Hi Cowabbi,
I had a look in my old akai X201D reel to reel tape deck which has a 50/60 hz option.
besides 100/110/120/200/220/240 volts ac in.

There is a lever which actually changes the belt to the different size pulleys on the main motor and flywheel drive to allowe for that. This deck has an ac motor for the capstan drive and two directly driven spindles for the reels. The extra loading on the motor is minimal with the frequency change.

My Akai X150D also has that feature, along with multiple mains voltage inputs.
They certainly were, along with BSR and Collaro, you'd find these in virtually all radiograms/portable record players up until the 1970's. Philips however used their own turntable which is a good example of a good idea but mechanically flimsy parts.

Pretty much the same as in Britain then. BSR decks were used in most of the cheaper-end machines, like portable "Dansettes," with Collaro and Garrard in the more upmarket models.

I know that at one time the classic Garrard 301 transcription turntable was used by the BBC (that was just the turntable -- a seperate tone arm had to be fitted).

No, Dual 721. Late 70ies model I guess. If I read the code on the manual correctly it was printed in 1976.

Ah, O.K., I was just wondering. I'm not familiar with that Dual model, although I'd probably recognize it if I saw it.

By the way, Thorens was also popular here in the high-end market.

It's a high-end model with an intimidating number of controls and screws for fine tuning the arm and everything... typical 70ies dark brown wood veneer case.

hello all......my rca record player is working fine and i decided to go with the inverter idea....however i have noise in the amp even tho ive replaced the filter caps.
any ideas how to get rid of it ?????
maybe higher value caps??????
what say you
kind regards

Try iron core filter chokes.

What kind of inverter is it? Personally, I wouldn't be happy with anything but a true sinewave output in this application.

I've built and used square wave solid state and vibrator inverters to run things for years; one of which was a valve radiogram. The low power synchronous motor isn't terribly fussed by waveform. From my experience, and your description of noise, it's an amplifier issue.
Being an AC/DC supply, these are more prone to mains borne 'interference', which in this case will be the very rapid change in voltage from the modified square wave, rather than a gradual change as per sine wave.
Generally a low value capacitor, say around .1uF rated at 250VAC will cure the problem if placed at the input to the amplifier supply.
Also, another thing to try is a capacitor across the rectifier's anode-cathode. Try .01uF 250VAC.
You can also try an inline mains filter.
Reversing the mains plug may also help.
Other things to look at are earthing issues.
Not knowing if the output of the inverter is isolated, I won't say try earthing one side of it, but earthing the 12V input can also help.

Thanks for your response aussie but i was using the inverter off a car battery not the household mains........I have now also tried a stepdown transformer and the amp works perfectly so i say its not an amp problem for obvious reasons in regard to the motor i would rather use the inverter, as the motor runs very hot off the stepdown any ideas???

It's sounds as though it's the output of the inverter. Whether square-wave (worst) or modified sinewave (not so bad), those steep transients are rich in harmonics and can cause interference.

Although I'd still prefer to start with pure sinewave, I'd agree that with suitable filtering you should be able to eliminate most of the noise.

Cowabbi,
All the suggestions I made were for running off inverter...as Paul says, the square wave supply is rich in harmonics; in otherwords, there's more than just a 60 cycle supply feeding your gramophone. 60 cycles is the fundamental frequency doing the work, but there's many multiples of this frequency which extend into the audio spectrum (and no doubt RF) which is why you can hear the buzzing. You need to incorporate filtering between the inverter and the 120VAC input of the amplifier which will round off the edges of the square wave. Earthing can also help if the interference is getting in by some other stray path.
When I posted my previous reply I forgot to ask if you had changed all the leaky capacitors, high resistors, and dried out electrolytics, but as you've mentioned the sine wave supply runs the amp ok then that's not the problem.
As the amplifier is only of moderate gain (one triode and one pentode) I don't think it would be too difficult to solve the problem.
By the way, does the inverter noise vary with the volume? If so, it indicates it's being picked up around the amplifier input.
As for the motor running hot on the transformer (ie. 50 cycle supply), maybe it is the lower frequency causing that, but would be a sign of a motor made with as few turns of wire (ie. cost cutting) as they could get away with. The other thing is the actual transformer...one of my stepdown transformers is actually 220 to 120V, so with 240-250V fed into it and a very light load on the secondary the voltage is rather high ~135v. I don't use it for lamps or things with valve heaters.
One other thing also with AC/DC gear, because of the way the valve heaters are supplied, the heater to cathode insulation can be fairly stressed depending where certain valves are in the heater chain, and if this starts to fail you'll get evidence of hum.

Hi there Aussie....Ive checked and indeed the noise goes up and down with the volume.
Ive also noticed that when you near the pick up or motor board the noise gets louder too.
Can you please please give me any suggestions.
Kind regards

It sounds as though the noise is being picked up on the tonearm wiring and/or the turntable chassis. I take it this is a unit with only a 2-wire supply cord and no ground on the deck?

Yes Paul you are quite right this player was built in 1951.....but I still dont understand why it only plays up on the inverter?
What can I do?

By the way....Im using a modified sine inverter
regards

Because the voltage waveform coming from the inverter is not the same as that which comes out of a domestic power point. To put it bluntly, it's horrible and noisy, but cheap to generate. A modified sine wave is merely a square wave with the same peak voltage as the mains voltage but with reduced duty cycle so the RMS (ie. the power that does the work...more correctly the equivalent heating power) is the same.
It is still full of nasty harmonics that find their way into everything. Hence the extra filtering and possible earthing required.

Here's a comparison. The blue line represents a true sinewave -- the type of power you get by plugging into a mains outlet.

The red is the type of waveform you get from a modified sinewave inverter. Those steep vertical sides to the waveform contain many harmonics, extending well up into the high audio and even radio frequency range.

Thank you so much for your responses gentlemen.
I now have, thanks to you, a better understanding of inverter power, however I still dont know how I would attempt to get rid of this noise, its like aussie said it has a hot chassis etc etc so how on earth can I earth the player to get rid of it.
Im at my wits end!!!!
Regards

First thing is to try earthing the 12v supply. Connect the negative terminal of the 12v input of the inverter to a metal water pipe, the earth pin of a GPO or some other object known to be earthed.
If the turntable is constructed on a steel chassis then try earthing that.
I know that some US made record players did not isolate the shield of the pickup cable so I'm not going to say go and earth that directly, though you could try doing so via a .01uF capacitor. Taking this a bit further, you can also try earthing the amplifier chassis via .01uF capacitor. Earthing via a capacitor like that will still allow the chassis to be live, but yet earth it at higher frequencies.

hello aussie.......
I have as you suggested connected an earth to the metal motor board and the 12v inverter input,while these connections did make a difference they only seemed to change the tune of the noise......and perhaps reduce it slightly.
I have purchased a .01 mf 275v poly cap..
should I connect this across the mains leads into the amplifier or on one side only ?be it active or neutral?
I have replaced the pick up cable and I can assure you it is new and properly shielded
kind regards

Cowabbi,
Be prepared for a bit of experimentation here...you might need to try different places to connect the capacitor and you also might need to increase it's value. Interference suppression is often more of an art than a science and what works for some things won't work for other things.
Try first across the 120VAC input where the mains lead is terminated in the record player.
Try from both sides of the 120V supply to the chassis of 1) the amplifier 2) the turntable.
Try from the shield of the pickup to the turntable chassis and then the amplifier chassis.
Try all these things with and without the earth connection to the turntable chassis.
Reverse the 120V plug in the inverter.
Try connecting the earth to each side of the 120VAC supply via the .01uF. Try connecting the pickup shield to earth via the capacitor.
If any of these start to look promising try increasing the value of capacitor; try .1uF.
Try also right across the 120V right at the inverter output socket.
If you're not getting anywhere there, get a mains suppression filter (not just a surge arrestor - that may not have any filtering) like used for computer gear( a 240V one is quite suitable), put 120V plugs on it, and connect between inverter and record player. You will probably have to earth the filter as the earth pin of the inverter socket will probably go to nothing.
Let us know how this lot goes