Pro-Ject 1 Xpression with an external motor: is it possible?

[egicar]

Hi all,

I'd like to know if anyone here knows if it is possible to use an external motor (like RM 9.2 setup) for a 1 Xpression turntable.
This idea comes from a radical solution of the "rumble" issue.
I searched in the web some informations about the RM 9.2 motor, but I didn't find them.
The most important information is about the correct platter/pulley ratio to have 33.3 rpm.

Thanks a lot in advance,
Egidio

[markcass]

Hi Egidio

The main problem I can see with using an RM/RPM 9 motor unit is that these decks have a belt that runs round the outside of the platter, whereas the Xpression has a sub-platter beneath, on which the belt runs. This means the ratio will be different.

It should, in principle, be possible to use this type of motor unit (the one from the RM1 Genie would also work) by ignoring the Xpression sub-platter, and running the belt round the outside of its main platter. Some modifications to the deck's chassis might be required to make everything fit.

Another way might be to fabricate a free-standing 'pod' to hold the existing motor, separate it from the chassis, and position it where the motor is on the standard deck. The deck would have to be cut away at the motor position to make space for the pod, but it would still look fine from above.

HTH

Mark

[egicar]

Many thanks Mark,

that's a very good idea: I'll study a system to completely isolate the motor from the chassis, without to have to cut the chassis. Maybe there could be enaugh room for a "thin" pod.
I'll report the results of my tests here.

Thanks again,
Egidio

[Garven]

Another way might be to fabricate a free-standing 'pod' to hold the existing motor, separate it from the chassis, and position it where the motor is on the standard deck. The deck would have to be cut away at the motor position to make space for the pod, but it would still look fine from above.

Actually this is something I considered just last week and mentioned in the rumble thread in this forum. I didn't follow through since the plastic covering over the bottom of the motor cavity is a one-piece that extends over to cover the power input jack.

Had it been just covering the motor cavity, I planned to set the motor into a large "blob" of blu-tac to support it and perhaps set the blu-tac in a small ashtray or similar container I might find at a local discount store. The idea would be to have the motor completely isolated from the plinth other than indirectly through the belt and the three pointed feet.

I might at some point investigate removing the plastic covering from the bottom and cutting off the motor cavity part but I mostly listen only to 33rpm LPs. Screwing the transit screws in tightly with blu-tac between the motor bracket and plinth pretty much removes all rumble for me at 33rpm and produces only a low-level 120Hz resonant hum when at 45rpm. So I'm good for now. I eventually hope to upgrade to a new turntable, hopefully one that won't force me to play around applying blu-tac inside it!