Music Hall mmf-7 spins faster

Thanks for your input, guys. But, Stefanl, lubricant to the bearing? Where exactly? Please elaborate.

Mofimadness: there's really no need for a strobe disc. My ears (and a couple of others) have indeed verified the (much) increased speed.

Dweller: I am pretty certain it's not high voltage. I live in Commack, New York (115V) and the added Pro-Ject Speed Box II -- suggested by Roy Hall himself and a couple of audiophile friends as well -- should have corrected any (major and/or minor) speed 'discrepancy'. In addition, I am using a Music Hall belt (the original one and a new one, bought directly from Music Hall). My line preamp is an Audio Research SP16L and my phono preamp an EAR 834P (with Cardas Golden Cross 1.0-meter interconnects). It does happen to all LP's, ever since I went back to analog about 6 months ago (the mmf-7 was stored in the attic for about 2 years). Lastly, the motor is "in the hole" of the plinth, as indicated.

I really don't know what else to do, except maybe buy a new turnatable, preferably from another manufacturer (maybe Rega or VPI). Roy Hall just sent me a new motor: I'll try it as soon as I receive it and report back to this thread.

It is indeed in the right groove, Eddaytona: the smaller one (and the larger one, as indicated, when I am using the Speed Box II).

Where is "as indicated" indicated?

The Speed Box appears to output 16 volts ac (VAC), while the MMF-7 appears to come with a 12 VAC wallwart power supply. I note that the ratio of 16 to 12 just happens to be approximately the same ratio as 45 rpm to 33.3 rpm. However the recommendation to use the larger pulley diameter with the Speed Box, for 33.3 rpm, would seem to make sense only if the motor speed were inversely proportional to supply voltage, which seems nonsensical. .

I don't know what kind of motor the MMF-7 has -- whether it is synchronous to the power line frequency, and what the sensitivity of its speed to line voltage is. But very conceivably it is different from the motors used in the Pro-Ject turntables for which the Speed Box is intended.

I would therefore do three things:

1)Try using the Speed Box while the belt is placed on the smaller rim of the pulley.

2)Try the 12 volt ac power supply from your friend's turntable.

3)Use a multimeter, set to measure ac volts, to measure the voltage provided by the power supply that came with your turntable, and compare it to what your friend's power supply puts out. Since you will probably have to disconnect the power supply from the motor to make that measurement, keep in mind that the voltage figures to be higher than it would be with the motor connected and running. Which is why I suggest comparing the readings of the two power supplies.

Re bearing oil, see page 14 of the manual for the 7.1, which I assume is similar to the 7 in that regard.

Regards,
-- Al

The recommendation for adding bearing oil is in the 7 manual also.Mobil 1 is the suggestion.Rega recommend 80/90 gear oil choice of oils could be important and if your turntable was in the attic for a couple of years,this is the first thing I would try.Make sure you coat the spindle and there is a coating of oil on the walls of the bearing recess and at the bottom of the well.Also play at least 1 album before you test and make adjustments.Warming the system up is crucial as well.

Thanks, Stefanl: I did read it in the manual. However, I am not sure what "main bearing" means. Where is it located: under (pardon my ignorance)? Please elaborate on the coating of the spindle.

As for warming up the system, it has been back out on top of my rack for more than 6 months now and I have played at leat 7 or 8 LP's so far, even with the atrocious (to my ears) speed problem, both with volume and mute.

I would appreciate any additional comments/advice (but I have yet to put electrical tape around the platter: it seems such a not so elegant trick).