Timing Edison DD phonographs

[fran604g]

Another important note I'd like to point out:

When the reproducer isn't on the record and the feed isn't engaged, the turntable rotates at significantly higher RPMs.

I'm concerned about this comment, Fran, because in my experience, engaging the reproducer should not affect the speed. If it does, something isn't adjusted and/or lubricated properly. I currently have a C-150, a B-19, and a C-19 in the house. I have tested and confirmed that all 3 run at the same speed whether the reproducer is up or down. All 3 of these have been serviced and adjusted within the last 2-3 years. Perhaps your motor needs a good cleaning and re-lube? I'd also check that your horn is set up correctly as described in the motor manual available on the board. I'll also be happy to answer any questions you have.

Cheers,
Kevin

Thanks Kevin, for the comment, I appreciate the feedback.

My mechanism is clean, adjusted to factory specifications and properly lubricated, I'm sure any number of factors can and do contribute to my experience, even the simple wearing of parts.

I probably could have used a better word than "significantly", what is significant to me, may not be significant to someone else, or mean significantly less.

I didn't mean to suggest that there was an enormous difference, but, it was significant enough for me to notice a drop in RPMs while viewing the strobe wheel. I'm sure that the added mass of the horn and reproducer assembly does affect the motor's inertia in some small way, how could it not? I'm equally sure that many people can point to many different experiences. Maybe I'm too used to timing/checking my Dual 1218 with the factory supplied strobe wheel. I guess that I was trying to stress the point that if folks get obsessively involved in trying to dial in their DD Phonos, engaging the drive mechanism can affect the RPMs to a certain degree even if it is infinitesimal.

How accurately would these machines have been measured when tested, I wonder? After all, there is a specified "tolerance" engineered into all manner of production.

Perhaps instead of trying state that a Diamond Disc Phonograph has to maintain precisely 80 RPMs with modern measuring techniques, we add a little tolerance to the specification, ie. +/- 2 RPMs?

After all, the method suggested to calibrate the turntable RPMs in the Mechanical Service and Repairs - New Edison Disc Motor is a "Pitch Pipe" that Dealers could obtain from Jobbers. How accurate could THAT be?

Best,
Fran

[Bruce]

Thank you to all those who have participated in this thread. It has been both very educational and respectful.

I do not play many records on my machines but I do take a lot of pride in making things accurate to the time of the original owners - which means running at the right speed. As a result of this thread I have given up timing with a stop watch and purchased an electronic tachometer as suggested earlier in the thread.

I paid a little more for the same device but went with a highly rated seller and have spent the better part of this morning adjusting my machines to the correct speeds. Wow how easy.

Thank you

Bruce