|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
70.117.113.124
In Reply to: RE: Papst motor rotation posted by MikeWI on September 27, 2015 at 08:27:17
Well I really haven't made much headway on my TT project, but now that I've finally finished the 3 month tube amp build from hell, I'll be able to focus more on the TT project.
I have thought of a motor control, but a true 3 phase supply is complicated and expensive. I'm thinking a single phase control that locks the motor in at 60hz would be sufficient for my needs. I'm only interested in 33 1/3 and 45 so the ROK L-34 could do that. If (and that's a big if) I can lock in the motor at 1850rpm, despite variations of line frequency, I think I'd be happy. I'm trying to find a DIY single phase 60hz supply, but haven't come up with one yet. Do you know of any?
I've heard that a 3 phase supply also makes the motor run smoother. My hope is that with a proper plinth, silicone gel isolation mounts, new idlers, a reworked bearing, and a few other tweaks, that I can get motor noise to a non factor. If not, I'll explore the 3 phase supply, however I doubt my finances would allow it (living on social insecurity now 8^).
I'm about to embark on the plinth stage, so thought I'd run my tentative plans by you, since you have a ROK. I'm thinking of spraying on a damping compound on the back of the top plate, but leave the area that mounts flush to the plinth masked off. That way, when the top plate is bolted to the plinth, any vibrations are better transmitted from the top plate into the plinth. I'm thinking of about a 50lb CLD plinth, made from layers of Baltic Birch and MDF. What do you think about the plinth plans, any advice?
BTW if you have the time, I'd like to hear about your ROK build, and any insights you may have. If you have any links to posts or photos of your ROK, that would be appreciated as well. Thanks Mike for your post.
twystd
Follow Ups:
I put Dynamat on the underside of the deck and the platter (leave room for the idler wheel axle) so I think the damping makes sense. It sounds like you are on the right track for the plinth. As long as it is not highly resonant or flexible, the plinth should work fine. I have to say that I haven't compared all sorts of options so take it for what it is worth. Here are pictures of my first plinth. My second is nearly identical with a larger top and the deck oriented normally (90 degrees CCW from this plinth) because I picked up a new B-12H with the tonearm section dead space cut off at the factory.
3 phase drive will also result in more torque because each winding is being driven appropriately rather than "faked" with a capacitor. I don't know of any DIY kits for this purpose.
Mike
Thanks for the link, I really like what you did with the plinth, gives me some inspiration. I'm having trouble justifying the cost of a 3 phase supply. From what I've seen, seems like they are $1k or more, that's almost the budget for my whole project.
twystd
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: