The issue could be the cell phone app. It stinks. Does the music have unstable pitch? Many have reported "problems" with speed after measuring rpm with the cell phone app. Apparently, a measurement of 32 rpm is not outside of the margin of error of the app.
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no it is actually the TT unfortunately.
I use the Eagle/Roadrunner from Phoenix Engineering with one of my other TTs. I know exactly what the difference is on the app and the actual rpm. The app was just to assess the drop in rpm which is about 2.0 change. Extremely audible change and slooooowing down of the music.....
The Artemis is a very thoughtful design which uses two pulleys, one to drive the belt and the other to push the belt up against the circumference of the platter so that the belt contacts the platter very nearly on its full circumference. This is to eliminate belt creep and along with the noncompliant belt, it probably works. Have you looked closely at the passive pulley? Is there any friction in it at all, when you turn it by hand? Could it be hanging up on anything? Likewise, can you check for bearing noise in the motor pulley? If the pulleys are blameless, then I'd think about the motor itself. I always like to eliminate the easy stuff first.
Did you have any luck with resolving the speed issue? I remember reading that each ps was matched to the motor in the deck, a task that required the use of an oscilloscope if so a plug in replacement is unlikely.
The ps was designed by John Atwood.
It seems the upper motor bush has run dry and worn, at least I can feel some play in it. I’ve been in the habit of leaving the deck running all day as the sound improves for the first hour after switch on, sometimes I forgot to turn it off before turning in for the night. This practice has been fine on previous decks with synchronous motors but the DC motor on the Artemis runs a lot faster.
The glue holding the pulley had softened enough that I could ease it off to get a bit of light synthetic oil to run down the shaft. I used a bit of Loctite 648 retainer to stop the pulley slipping, not sure about my choice there but it’s what I had.
The speed was still unstable with the Artemis ps at first but a lab power supply set to around 6.2V gave 33 1/3 rpm on a strobe disc, the current draw was initially near 0.1A but after running a few days this had dropped to 0.02A. With the main bearing nicely warmed up the deck would now run stably on the Artemis ps but the next morning starting afresh I was unstable again for an hour before I gave up. A few days later I started it up again and it settled after a few minutes.
Ideally I’d like to replace the motor and do it myself but the Artemis ps needs matching to the individual motor and I’ve not discovered how to do this, there are two trim pots inside the case so potential to get it really wrong. The lab ps makes the deck sound really ordinary so that’s not an option for running it. I’m resisting the temptation to investigate further, for now.
If you used any motor with a speed adjustment function, then you would not have to worry about matching the motor to the turntable. You would just observe the initial speed error and use the adjuster to correct it. Have you considered adapting the eclipse motor system sold by SOTA to the Artemis? If you are happy with the Eagle/Road Runner, you will be equally happy with the eclipse, since the two emanate from the same inventor.
Thanks for the suggestions
just for context I have 8 TT - two are DD, 3 belt and 3 idler ...
Each has its own strengths and signature sound
The Yamaha GT-2000 is great (full Yammy stack) A’s is the Garrard 401 or 301
the Artemis is part of a full Artemis system and it works well when running correctly- given that the belt is an actual R2R tape with a tensioner it is different from the VPI or Fairchild 755...
After getting a few microlitres of oil into the motor and letting it soak in the deck is running reliably again and sounding its old self. Also the motor noise, which was audible up close from the time I got the deck is now just about inaudible. What I’d put down to the brushed nature of the motor may have been the bearings running dry.
An oil called “liquid bearing” was recommended but not easy to obtain outside the US so I used a bit of SAE5 synthetic I had handy.
The difference between the Artemis ps and the lab ps was interesting, With the lab ps set to a fixed voltage and current set to 5Amax (but drawing around 0.03A) making the deck sound very ordinary in comparison to the Artemis supply.