Music Hall mmf 7.1 US to EU conversion

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bjorn
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Music Hall mmf 7.1 US to EU conversion

Post by bjorn » 24 Aug 2019 15:37

Hi Everyone,
I've recently moved to Germany from the US, and of course brought my Music Hall 7.1 turntable with me thinking that it shouldn't be too hard to find the parts necessary to get it running properly. Unfortunately, it's been quite the headache finding a straightforward way to order parts for this 'table. I've searched online extensively but the Music Hall parts selection is very limited in mainland Europe. I've contacted a few Music Hall dealers in Germany but they've been quite unresponsive. I need a 220v AC adapter and the EU version of the motor pulley to get it to play at the proper speed.

-I think I can get a pulley intended for the Pro-Ject RPM 9 model lineup by ordering one from the UK, as far as I can tell it's the same motor as the Music Hall, but if someone could confirm that, that would be fantastic.

-I thought I had a universal AC adapter that would work, it fits and puts out the required 15v. But when I plug it in the motor lights up, but won't turn at all. The only difference with this adapter that I can see is that it is rated at 1.6A, whereas the original was rated at 550MA (I think...). Would that explain why the motor won't turn? Please tell me I didn't fry it :oops:

Any tips would be greatly appreciated!

Coffee Phil
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Re: Music Hall mmf 7.1 US to EU conversion

Post by Coffee Phil » 25 Aug 2019 07:37

Hi Bjorn,

Music hall does not give much information in their user manual but it appears your motor requires 15 Volts AC, 60 Hz. I’m wondering if you purchased a DC power supply.

I you find a 15 VAC source the motor will run by at 5/6 the speed it runs on 60 Hz. That is fine if you can secure a 50 Hz pulley. If you cannot you will need a 15 volt, 60 Hz source of sufficient accuracy and stability.

Phil

bjorn
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Re: Music Hall mmf 7.1 US to EU conversion

Post by bjorn » 25 Aug 2019 08:54

Thanks for the input. The adapter I tried says "Switching Adapter/AC Adaptor" on it, so that might be the problem...

Yes, the old US adapter provided 15 Volts AC, 60 Hz. I'll do some digging, but is it even possible to find an adapter that can convert 220v/50hz to 15v/60hz? If so I can avoid changing the pulley.

Coffee Phil
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Re: Music Hall mmf 7.1 US to EU conversion

Post by Coffee Phil » 25 Aug 2019 22:17

I found this:

https://www.amazon.com/LiteFuze-Travel- ... way&sr=8-3

It almost seems to good to be true, but it seems that they explicitly claim that it changes frequency. There is no claim on frequency accuracy which matters for speed accuracy. You might ask some questions and if the frequency accuracy is better than +/_ 0.5% give it a try.

Phil
bjorn wrote:
25 Aug 2019 08:54
Thanks for the input. The adapter I tried says "Switching Adapter/AC Adaptor" on it, so that might be the problem...

Yes, the old US adapter provided 15 Volts AC, 60 Hz. I'll do some digging, but is it even possible to find an adapter that can convert 220v/50hz to 15v/60hz? If so I can avoid changing the pulley.

bjorn
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Posts: 95
Joined: 25 Jan 2009 14:46
Location: Munich, Germany
Contact:

Re: Music Hall mmf 7.1 US to EU conversion

Post by bjorn » 27 Aug 2019 15:44

Thanks for finding that. I have some possible solutions in the works but if those don't pan out I might snag one of those converters when I visit the US later this year.

I was able to find a 15v AC/AC adapter which should work: https://www.amazon.de/gp/product/B07CKZ ... UTF8&psc=1

I also snagged a 50hz Pro-Ject pulley off eBay... it looks like mine but may not be an exact match. It was relatively cheap so I took a shot at it. The Music Hall dealers here in Germany insist that I have to buy a whole new motor, which I know isn't true. I was really happy with my turntable, but after this experience, I would definitely have bought a different one if I had to do it over again.

Coffee Phil
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Re: Music Hall mmf 7.1 US to EU conversion

Post by Coffee Phil » 28 Aug 2019 01:25

Hi bjorn,

That adapter which you linked is simply a transformer. It will not change frequency. Your motor should turn but it will turn at 5/6 the speed which it turns on 60 Hz. That is fine if the pulley which you bought is correct. The pulley will not be an exact match. It should fit the shaft of the motor but the diameters of both the 33 1/3 part and the 45 part should be 6/5 the diameters of the corresponding parts of your 60 Hz pulley.

Be careful changing the pulley. If it has a setscrew it should not be too difficult. It it is a press fit, I would worry over bending the motor shaft. If you can't find a proper puller, take it to a machine shop.

I favor leaving the motor be and work on supplying it 15 volts @ 60Hz. I'm a bit skeptical about the adapter which I linked but try to contact them and ask questions.

Alternatively you can put together your own 60 Hz source. Here is my "redneck" speedbox experiment:

https://www.vinylengine.com/turntable_f ... 542/medium

This is an HP function generator driving an audio power amp with an AC sine wave. This turntable has a 120 volt motor so a transformer is after the amp to step up the Voltage. You should not need the transformer as a modest power amp should be able to supply 15 Volts RMS. A used function generator or audio generator as well as a suitable amplifier can be found on eBay for reasonable cost.

Phil

bjorn wrote:
27 Aug 2019 15:44
Thanks for finding that. I have some possible solutions in the works but if those don't pan out I might snag one of those converters when I visit the US later this year.

I was able to find a 15v AC/AC adapter which should work: https://www.amazon.de/gp/product/B07CKZ ... UTF8&psc=1

I also snagged a 50hz Pro-Ject pulley off eBay... it looks like mine but may not be an exact match. It was relatively cheap so I took a shot at it. The Music Hall dealers here in Germany insist that I have to buy a whole new motor, which I know isn't true. I was really happy with my turntable, but after this experience, I would definitely have bought a different one if I had to do it over again.

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