VPI HW-19 Upgrade question SAMA or SDS?


OK, the upgrade bug has bitten again, and I know that ther are a number of folks here that have lots of experience with their HW-19.

I have a VPI HW-19 Mk III that I recently upgraded to a Mk IV with a TNT platter with an inverted bearing. Also, it has a sorbathane puck suspension rather than springs, and I've replaced the rubber feet with cone type spikes. The table dead level sitting on top of a 1-1/2"-inch thick maple top shelf of a very heavy flexi-rack. I'm using an ET-2 arm connected to my shop compressor with four stages of precision air-regulation with the final stage adjustable just before at the entering the ET-2. I just air-up the compressor's 30 gallon tank, then kill the compressor so that it won't start back up, and I can listen for hours (wife think that I've lost my mind every time that I do this, but that's another story). Also, I'm currently listening to an AT33PTG that I have come to really like. The phono section is a Threshold SL-10 upgraded with Black Gates throughout.

The Mk IV upgrade made a real difference from the Mk III. As I quickly found out, the Mk IV presents a fuller soundstage and better base than the Mk III platter/bearing. I view that upgrade as well worth the money, especially buying it used here on A'gon.

Here is my dilemma with funds being limited to purchase only one or the other at this time, but not both - at least for now.

What do you think would be the best upgrade for this HW-19? A new SAMA for $400, or a used SDS for $600 to $800? Used SAMAs never seem to come up for sale, but you can always find a used SDS on Audiogon. I think that there are at least three available for sale here as I write this.

Also, if someone thinks neither mentioned upgrade would be cost effective, and that money would be better spent with an upgrade elsewhere, please say so. I'm trying to keep my mind and ears open - for better sound!

Thank you!
forrestc
I would not bother with the older motor control units. I used the original with a HW19 for a while, and thought that it caused more problems than it solved. The current SDS is the way to go.
Correct me if I am wrong, but the SDS controls speed by regulating the power being fed to the motor,thereby not only controlling the speed but preventing voltage fluxuation causing speed differential.
Assuming that this is correct,don't both the new and older version accomplish this? One has a digital readout(newer should be cheaper but isn't) the other is analog (older version).
Frogman, how did it cause a problem?

If what I think is correct,this thing is nothing more than a voltage regulator.Sounds like a DIY project.

After all VPI wants close to $1000.00 for the new version.Out of my recession league.

thanks guys

e
For what it's worth, I use the Carbon Fiber Isolators (two different types of sorbothane sandwhiched in with two layers of carbon fiber. I got tired of the springs a long time ago. The height of these isolators is just about right ( of coarse you have to raise up the SAMA which I do right now with the Maplshade rubber/cork laminations. I am pleased with this setup over the springs. I also recently got an SDS and I was smiling all the way through my 12 hour listening session last Sat. I'm going to try some of the silk string. I recently bought a new "black" belt before I got the SDS, and it was a noticable improvement in PRAT over the original belt. As far as isolating the TT, I use a custom MANA Acoustics Reference wall shelf and have replaced the glass for BDR the source shelves. My wall unit is isolated from the wall w/ 1+1/4" strips of Dynamat placed at 45degree angles then (2) 1x12 oak board screwed to the wall and the wall shelf is attached to that. The wall is stiffened and I have a lot of isolation too.It all worked out very well. The Mana and the BDRs are expensive but well worth it and they were made for each other, a excellent match. A lot of money but this is my one and only source and I'm HAPPY.
I got the "black" belt recently and I experienced the same thing concerning "PRAT".

I have been curious about the silk thread.Is there any problem with the motor pulley shape with a thread? Does it give it more PRAT?
The only thing to worry about with the thread is the size of the knot. With a thick string it could cause a small thump. Just use a basic over around and through (not a square knot or a bloodknot) with the thinner string.

My pully is V shaped. If you have the flat one it will be OK too, as long as the level of the pulley and platter are OK so it doesn't travel.

Now I haven't heard string directly against the rim drive but I've been told that it has the PRAT of a rim drive without the rumble of a rim drive. I believe it based on what i hear.