Sota Sapphire refurb

griffithds · « **Reply #20 on:** 19 Sep 2013, 02:02 am »

Hi Neobop,

Going through some old stuff, I have discovered a bag of those lead shot weights that SOTA uses for balancing. Do you need any. They are the SOTA original item. If the shipping isn't to much, I'll ship them free. I refuse to throw out anything related to audio. The "might need it some day" is very strong in this household. Let me know if they can be of some use to you.
Regards,
Don

shooter · « **Reply #21 on:** 19 Sep 2013, 04:13 am »

I still have my star sapphire from the 80's, the dealer use to demonstrate it by banging on the chassis of the turntable while playing a record, never skips and hardly any feedback through the speakers, the spring system of the Sota is very effective in isolating vibrations.
Does it sound better without springs? I have no idea.
BTW to set up the table correctly you need the full weight of the lead shots that came with the table.

neobop · « **Reply #22 on:** 19 Sep 2013, 05:05 pm »

Griff,
Thanks for the offer. I'm not sure what I'll wind up doing. In the event I need some more of the lead shot, I'll get in touch.

neo

neobop · « **Reply #23 on:** 19 Sep 2013, 05:09 pm »

Shooter,
Do you know the procedure for setting up the table using all the weight? Add the arm then subtract weight until platter is level?

neo

shooter · « **Reply #24 on:** 19 Sep 2013, 08:05 pm »

This is from my memory, first put the full bag of lead shot in the well and level the table, remove the lead shots and install the arm, put a level on the platter and fill the well again with the lead shots until the table is level again, the older arm board has a hole above the well for adding the lead shots.
I use a small ziplock bag to contain the shots in the well for ease of removal.

Grbluen · « **Reply #25 on:** 20 Sep 2013, 03:59 pm »

Neo,
FWIW, I'm using modified video tape on my Scout and I believe it's worthwhile investigating. I have all the materials if you're interested.

Don grb

neobop · « **Reply #26 on:** 20 Sep 2013, 07:03 pm »

Don grb,
Thanks for the offer. These are interesting propositions, especially for old DD/rim drive guy like me. Maybe I can get satisfactory speed stability out of it. I remember the last time I set it up ('90s), I bought a new belt and it was smaller in width and thickness than the original belt. It was apparently from Sota, through a vendor and was their newer replacement. It came in a little bag that said Sota. I couldn't believe how much worse it was.

It seems to me this should have the potential to have decent speed stability. The power supply is 24V DC, so I assume the motor and controls, even if not the very best should be pretty good when properly coupled. My real inclination is to scrap the drive system altogether and get a Teres Verses. I could even fit it inside the plinth by cutting away part of the subchassis and having it sit on the shelf. But I'm trying to look at this as a belt drive challenge.

I saw Origin Live makes a replacement DC motor/controller that starts at $500. Looks nice but you still need some kind of belt.

The attraction of dental floss is, it won't stretch under this amount of tension (I think), but the knot might be a problem, I'm not sure.
Tell me about modified videotape. Do you cut it in a thin strip then splice it?
neo

Grbluen · « **Reply #27 on:** 20 Sep 2013, 08:40 pm »

Neo,
I'm using the mylar streamers as suggested by Doug Deacon and his thread from AudiogonE. Basically it's a Mylar strip with the same dimensions as videotape, but textured on one side. Using an acid to etch away the reflective material, you are left with a belt that exhibits little to no stretch. I think Doug has done a fair amount of work comparing the silk threads, standard videotape etc., and believes this one to be best.

Don grb

Russtafarian · « **Reply #28 on:** 20 Sep 2013, 09:55 pm »

Quote

Russ,
Here's what the springs look like:

Thanks. I've had the table completely torn apart to to figure out what to do with the stretched out springs. The springs in the front hang so low the bottom plate hits the rubber footers. I tried rotating them, front springs back, back springs front, but that wasn't enough.

If I can find a way to fix the suspension without a big hassle or expense, I'll take another run at resurrecting the Sota. For now I got it rolling with a cheap cartridge and beat-up MMT arm and gave it to a friend so he can listen to his garage sale vinyl.

Russ

neobop · « **Reply #29 on:** 22 Sep 2013, 11:28 am »

Quote from: Russtafarian on 20 Sep 2013, 09:55 pm

Thanks. I've had the table completely torn apart to to figure out what to do with the stretched out springs. The springs in the front hang so low the bottom plate hits the rubber footers. I tried rotating them, front springs back, back springs front, but that wasn't enough.

If I can find a way to fix the suspension without a big hassle or expense, I'll take another run at resurrecting the Sota. For now I got it rolling with a cheap cartridge and beat-up MMT arm and gave it to a friend so he can listen to his garage sale vinyl.

Russ

I've been thinking about this and it doesn't look like there's a quick/easy/cheap fix. I haven't spoken with Sota since I found out the voltage of the power supply, years ago. I'm guessing that a set of replacement springs would be $200 or more, maybe much more. There would be a number of options for defeating the suspension entirely.

It's been a long time since I took this apart, so I just looked at it again. The problem with the suspension is the motor/pulley is fixed while the platter moves with the suspension. Every time the platter moves, the belt rides up and down the platter. If there's any lateral movement at all, it's disastrous. The belt will stretch and contract in response to the movements. Usually, when playing a record there isn't much movement so you can get away with the situation, but if you can figure out a good way to defeat the suspension I'm quite sure you can get better performance. If someone has a good suspension they could do a redesign and mount the motor on the subchassic and run wires to the controller. Seems like more trouble than it's worth. I don't think it needs a suspension anyway. This thing is built like a tank, all full of MDF, lead sheet and lead blocks means it will stay in motion longer once excited.

Russ,
I imagine your friend has some blocks under the subchassic holding it up? Probably not a bad solution even if it seems a little crude. I'm now thinking about a good way to defeat the suspension. I suspect something a little more rigid like steel, would be good.
neo

rich2ch · « **Reply #30 on:** 22 Sep 2013, 07:56 pm »

Neobop,

You may have moved beyond this but the last time I did work on my sapphire I think the springs were only $80 for DIY installation. It sounds great now! Sota was very helpful the times I called. Mine is a III deluxe. Yours looks like an earlier model than mine and it had aluminum angles attached to the sub-chassis. I have a photo of it but was unable to upload it to this site for some reason.

neobop · « **Reply #31 on:** 23 Sep 2013, 12:13 am »

Thanks Rich2ch, that's good to know. I wonder if Sota changed hands in the last few years. That was a really terse letter sent to the guy on Karma.

I think I'm going to defeat the suspension w/o removing the springs. I'm pretty sure that's the way to go, but I'll be able to reverse the mod if it doesn't seem like an improvement.
neo

griffithds · « **Reply #32 on:** 24 Sep 2013, 02:07 pm »

Hi Neo,

Last I heard is that the employees bought the SOTA facility. Not currently owning a SOTA (to my regret), I have not kept up with how they currently operate. If you run across additional/current information about them, please let us know. Like many products in this country, the one with the most advertising dollars gets all the press coverage.
They are beautiful sounding and a stunning looking table. You would do yourself proud to restore it to all its previous glory.
Regards,
Don

neobop · « **Reply #33 on:** 24 Sep 2013, 05:37 pm »

Quote from: griffithds on 24 Sep 2013, 02:07 pm

Hi Neo,

Last I heard is that the employees bought the SOTA facility. Not currently owning a SOTA (to my regret), I have not kept up with how they currently operate. If you run across additional/current information about them, please let us know. Like many products in this country, the one with the most advertising dollars gets all the press coverage.
They are beautiful sounding and a stunning looking table. You would do yourself proud to restore it to all its previous glory.
Regards,
Don

Hi Griff,
If the employees bought the company, they have yet to update the web site.
http://www.sotaturntables.com/aboutus.htm

I noticed that a refurbished Sapphire series 5 sells for $2700. Mine is a series 2 or 3, not sure. Old ones like mine sell for around $600 w/o arm (last I checked). I can appreciate your nostalgia, fond memories, but I don't share them. I always liked the way they look, but my main consideration is SQ.

Anyway, I haven't done any mods yet and I'm thinking of just reassembling it first and trying a different kind of belt. Based on my previous experience it's an exercise in futility, but maybe a better belt will be enough of an improvement. I recently saw a used Goldmund Studio w/o arm for around $2700 on Agon. It was 230V, but I know which one I would go for if it was viable. I guess that's neither here nor there. Want to buy my Sapphire? It has an improved power supply, supermat, and big reflex clamp.

I just bought some steel corner braces and long 1/4" brass bolts that will go straight through the top and lock the subchassis. Not sure when-if.
neo

neobop · « **Reply #34 on:** 24 Sep 2013, 05:43 pm »

Don grb,
This videotape belt you mentioned - what do you do about length, splice the tape? How about width, videotape is around 1/2". do you just cut it thinner to fit the pulley? Seems like it might be a great solution.
neo

griffithds · « **Reply #35 on:** 25 Sep 2013, 03:31 am »

Quote from: neobop on 24 Sep 2013, 05:37 pm

Want to buy my Sapphire? It has an improved power supply, supermat, and big reflex clamp.

I just bought some steel corner braces and long 1/4" brass bolts that will go straight through the top and lock the subchassis. Not sure when-if.
neo

Hi Neo,

You have once again made me smile. 6 months ago I might have taken you up on your offer. But at the moment I have far to many unfinished projects sitting around already. My other half (the better half), has been complaining about all the items that I have stored in the garage so I would rather not "rock the boat" sort of to speak. (grin)
Regards,
Don

Grbluen · « **Reply #36 on:** 25 Sep 2013, 09:47 am »

Neo,
Yes, the mylar is spliced. I'm using Scotch gloss finish multitask tape, although video splicing tape is recommended. I made a new capstan for the motor to accommodate the tape dimensions.I suppose the mylar could be cut to a smaller width, but it sounds like it could be tedious. The way that I have the table set, the exact length of the belt is not critical because the motor stands alone. If your motor is "captured", I'd imagine it would be more of a trial and error affair.
Let me know if I can be of assistance, as I have more than enough material.
Don

neobop · « **Reply #37 on:** 28 Sep 2013, 02:04 pm »

Other than fixing a broken wire going to the power supply, I haven't done anything else. I've been mulling over my options.
Because I'm not going to replace the motor at this time, that reality dictates my course of action. I'm quite sure that defeating the suspension will improve performance if the pulley remains fixed. Because of space limitations there doesn't seem to be any way to mount the existing motor on the subchassis and keep the controls where they are.

Anyone with an old Sapphire like this, here are the options as I see it.

1) Keep it as/is. Maybe you could find/make a better belt than stock. That's really a mess.

2) Keep the suspension and replace the motor with one that can be mounted on the subchassis. The Origin Live motors with external power supplies and controllers look great. They cost between $500 and $1200, depending on model. There's 2 different motors and supplies and an optional upgraded transformer. This would require rebalancing the weight distribution. More weight would be necessary on the tonearm side or less on the motor side, and/or a combination of both.

3) Keep the motor as/is and defeat the suspension. I suspect this is the most cost effective upgrade. This 4 spring suspension isn't exactly precision to start out with. It relies on weight to keep it stable, but isn't tunable to give you a perfect up/down bounce. Even if it does, the motor doesn't go with it, so what happens with the belt?
I read that Sota now mounts the motor on the suspension on the Cosmos. You don't have to be a physicist to see the advantage. I haven't tried it out yet, but I'm quite sure this table is better without a suspension if the motor remains fixed.

4) Use the platter, bearing and subchassis in any configuration you like with a Teres rim drive motor. This is a very nice platter and the mat/clamp is excellent. With this combo I think you could have a first rate table that wouldn't cost 20 grand, although the motor is $1800.

For anyone interested, there's a thread on Karma with a series 1 Sapphire restoration.
http://www.audiokarma.org/forums/showthread.php?t=545911

neo

neobop · « **Reply #38 on:** 16 Oct 2013, 01:41 am »

I caught same kind of flu or bug so I haven't made a lot of progress. I took some photos - thought you might be interested in seeing how this is built and what I'm doing.

At the top of the picture you see a steel brace I cut to use as a corner brace between the top and the front panel. It's sitting on the springs so it's not seated. There's also one for the back.
In the lower right corner near the armboard, you can see how the springs are seated.

The center of the spring recess is marked and I'm going to drill right through the top piece to mount 4 - 1/4" brass bolts. Those washers are approximately where they will be. Those bolts go through the subchassis where the springs were bolted down.
I had already replaced lost screws securing the motor cover with brass. I think it should look okay.

Abandoning the suspension allows some redesign. Those heavy blocks at the corners (lead I think) will be used on either side of the bearing support housing. The housing is secured to the subchassis with three small bolts. The blocks will keep it steady and hopefully absorb any vibration.

I also have additional steel braces for the chassis. Two other things I was thinking of doing were to use a couple of corner braces between the sides and the subchassis for further support. Everything bolts through the subchassis so it can be disassembled. The other thing is to redesign the armboard and mount. I'm quite sure I can improve it, but maybe I'll get it back together first and get it going.
neo

neobop · « **Reply #39 on:** 31 Oct 2013, 02:03 am »

I was figuring out the logistics of all the mods when it occurred to me, there might not be a need to bolt the plinth on the subchassis. If I install a spike where the spring seats were I could have the subchassis stand on its own and the motor/plinth separated from the rest. Sort of like having a motor separate from the table.

This is the bottom of the chassis:

The rubber feet are on the plinth - spikes on the subchassis:

Eureka!! it actually works. Still have a lot of work to do. I need more weight on the plinth, but all the bracing and reinforcing the top panel doesn't seem quite as urgent. I'm thinking of getting some sorbothane washers for the motor mounts. Don Grbluen kindly sent me some stripped video tape to make a belt and that will take a little doing, but the latest approach will allow some adjustment of the distance between the pulley and platter. I was wondering how I would get the belt installed. The tape won't stretch like a rubber belt.
neo