Pro-Ject Motor and SpeedBox with AR Turntables?

[JXO]

Has anyone considered or attempted to install a Pro-Ject replacement motor/Speedbox combination in an AR turntable? I have The Turntable with Merrill mods. Any reasons why it won't work?

My understanding:
1. Replacement motors are $30, low voltage (with theoretical benefits therefrom) and not a direct drop-in replacement but appear mountable in an AR
2. I don't have the exact specs on the motor; is it safe to assume it will do 300rpm with 60hz?
3. Am told the new replacement motor is compatible with the Speedbox ($120) which will be needed b/c of the voltage spec
4. Don't know if AR pulleys fit on the drive shaft
5. The motor can be hard wired to the Speedbox for power supply and speed control.

Worth a try or a waste of time?

[danieldust]

I can't answer any of your questions, but I like the idea. Let us know if you "take the plunge."

[JXO]

I can't answer any of your questions, but I like the idea. Let us know if you "take the plunge."

Daniel says he has a whole box of tools he's willing to loan you, and the expertise.

Plunge is underway. Will keep you posted.

[snfrosten]

If you are going to use the AR platter and mount the motor in the same spot as the AR motor you will need to use the AR pulley and belt. This means the motor has to run at 300 rpm to keep the platter rotating at the right speed. If the speed box is adjustable then it should work if the motor is not a 300 rpm.

Let us know if it works.

Steve

[JXO]

The Project replacement motor arrived today. $30 from Needle Doctor. Fit and finish look good.

On the Box:
Type: 9423 90 000
Motortek 9423
16v 60hz 2va 300n./min.
Made in the Czech Republic

On the Motor:
Pro-ject
Synchromotor
M400
Hz 50 60
C 8u2 8u2
ot/min. 300 360

The motor size and weight is very similar to my Hurst replacement.

The drive shaft on the Pro-Ject is nearly identical to the Hurst. Length is a hair (literally) shorter and the diameter may be very, very smaller. But these difference are minuscule and should not affect pulley connections or pulley height.

It has a mounting bracket with holes positioned exactly the same as the Hurst.

4 bare wire leads (narrower gauge than the Hurst wires).

So it should be a clean drop-in replacement for the AR motors.

The box and the motor present an inconsistency: the box suggests that the motor will spin at 300rpm at 60hz but the label on the motor indicates 360rpm at 60hz. So I am not sure which pulley will work on this thing.

Thoughts or guesses? If indeed it's 360rpm at 60hz, is this a failed mission or will I be able to use the Pro-ject replacement pulley to get me spinning at the right speed? I have also read somewhere that the speedbox may convert the main power from 60 to 50hz. see http://store.acousticsounds.com/browse_ ... =equipment

Once my AR comes back from the dealer (new cartridge and tonearm cable), I will confirm that the motor will install easily and I will likely go ahead and order a Speedbox to power it up. I am hoping that the bare wires on the motor can be hardwired to the Speedbox b/c the motor does not have a plug (the speedbox appears to connect to the motor with male and female power plugs). Then I will confirm the speed and the pulley.

[JXO]

Speedbox manual is found here

http://www.project-audio.com/inhalt/en/ ... eedbox.pdf

the manual suggests that with 60hz models, if the belt is placed on the larger part of the pulley, it should spin properly. So the AR pulleys should work fine provided I can connect the motor to the speedbox.

[danieldust]

I know almost nothing about electrical stuff, but it sounds to me like you need to have the motor wired to the proper kind of power jack/recepticle to accept the plug from the speed box. (And I wonder why the speed box didn't come with the plug.)

Then you find a nice way to install the jack and motor in your turntable, and you have a very nice little upgrade.

Seems like a visit over to the Project/Music Hall forum might be in order. Maybe one of those guys can give us a picture or at least a description of what kinds of plugs you're supposed to be dealing with.

[Ernie L]

Interesting project..thanks for sharing

[JXO]

I know almost nothing about electrical stuff, but it sounds to me like you need to have the motor wired to the proper kind of power jack/recepticle to accept the plug from the speed box. (And I wonder why the speed box didn't come with the plug.)

Then you find a nice way to install the jack and motor in your turntable, and you have a very nice little upgrade.

Seems like a visit over to the Project/Music Hall forum might be in order. Maybe one of those guys can give us a picture or at least a description of what kinds of plugs you're supposed to be dealing with.

I understand that the Speedbox comes with its own wall wart power supply. the only question is how to connect the speedbox to the motor. the Speedbox comes with a cable and socket (for connection to the motor) that expects some kind of plug on the motor end. I am hoping that I can simply cut the socket off the Speedbox cable and hard wire it to the bare leads from the motor.

[JXO]

...Seems like a visit over to the Project/Music Hall forum might be in order.

Done.

[MuZak]

Hey JXO..

First off, welcome to the forum!!!

Nuthin we like better here than some who jumps right
in, right after joining to produce some useful info!


So how'z it comming along?

I can't answer any of your initial questions, but
you asked if its worth a try....
I think so, if you don't mind the effort.
It would be nice to find an inexpensive and, hopefully,
relatively easy motor solution for the ARs.

First off, which AR do you use... regarding the
"drop in replacement" hole spacing?

Next:
You said the shaft diameter is very much smaller..
I think you meant similar??

You'd think there'd be an easy way to connect
a replacement motor and speedbox from the
same manufacturer.
How is it done in the table the motor is a replacement for?

Best of luck!
Keep us posted.

Greg

[JXO]

First off, which AR do you use... regarding the
"drop in replacement" hole spacing?

Next:
You said the shaft diameter is very much smaller..
I think you meant similar??

You'd think there'd be an easy way to connect
a replacement motor and speedbox from the
same manufacturer.
How is it done in the table the motor is a replacement for?

1. The Turntable circa 1984. With Merrill mods from about 1991 and some recent ones from Anthony. I don't have my turntable at the moment-- it's in the shop, so I compared the Pro-Ject motor to a Hurst replacement motor that I have had for 8-10 years. I assume the Hurst will drop in to my turntable. The size, weight and mounting on the Pro-Ject motor is almost identical to the Hurst.

2. The shaft diameter looks smaller but by a very, very small amount.

3. The Speedbox unit comes with a connecting cable that may look like an AC power plug/socket (I say may b/c the manual and product literature is not clear). It appears that the Pro-Ject turntable motors connect to an internal power supply or connection device inside the turntable and the Speedbox is designed to plug into this internal terminal/connecting device in the turntable. The ARs, obviously, don't have this plug or socket and the only remaining question for me is whether and how the motor can be connected directly to the Speedbox. Questions have been posted on the Pro-Ject forum and sent to Pro-Ject and Sumiko (US importer). We shall see.

[JXO]

Useful images of the Speedbox can be found here:
http://store.acousticsounds.com/browse_ ... e_ID=33715

While these pix are of the Music Hall device, I understand that the Pro-Ject Speedbox is identical. I am told the SpeedboxII comes with its own wall wart power supply which plugs into the empty female power socket shown. The cable shown is designed to plug into the Pro-Ject motor (I assume their decks come equipped with some kind of connecting device on the outside of the plinth). As mentioned, the replacement motor does not come fitted with a socket to receive the plug. I hope that we can either: 1) fit a cable with a socket to the wires running off the motor or 2) simply cut the plug off the Speedbox cable and splice it directly to the motor.

Thoughts?

[MuZak]

Hey JXO...

1) I believe... (99% sure) the Hurst is a drop in
for your table, re: hole spacing.

2) A little smaller should be ok.
bear in mind that the AR pulleys can be crimped
a bit, but BE CAREFUL!
Its easy to distort them and get em on crooked..
(wobble=bad)
You can put a little slit across the center of the opening
(on the bottom) with a razor knife if you work at it.
Give me a hollar if you need assistance with this.

3) I find it odd that a replacement motor doesn't
come with whatever it takes to connect it attached.
Heh.. an unclear manual.... surprise surprise..

I went and saw your post in the MH/Project forum.
I would think that however its connected inside of those
tables will provide the answer.

If no replies from them, perhaps there's a manual in the
Library under those brands that shows how
things are wired underneath?

Good luck!
Greg