Anyone Familiar with the ACOS GST 801 Tonearm?

[Mister Pig]

I got some questions regarding the set up of tracking weight via the magnetic ring. There are a couple of things that need to be worked through. First of all, the counterweight must be the light version as it will not allow me to zero out this Fidelity Research cartridge. I added some weight to the back of the arm temporarily to be able to do so. This is with the VTF ring set at the 0 grams setting. Once that is done, as I understand it I am supposed to be able to move that VTF dial to the appropriate tracking force setting and be ready to go. When I do this, I do not get a change in tracking force. Have I misunderstood the process? I can set tracking force manually with the counterweight like a traditional tone arm, but I like to have things working like they are supposed to.

Anyone with any experience with this model of arm?

Regards
Mister Pig

 

[KentTeffeteller]

I don't know. Is this Acos tonearm similar to the Rega R200 (Acos manufactured that arm).There might be documentation for that arm.

 

[chaz]

There is a manual for the ACOS Lustre GST 801 at VE that might also help:
https://www.vinylengine.com/library/acos/lustre-gst-801.shtml

 

[Mister Pig]

I don't know. Is this Acos tonearm similar to the Rega R200 (Acos manufactured that arm).There might be documentation for that arm.

No. this was their TOTL arm. As I understand it this was a Koshin design.



Regards
Mister Pig

There is a manual for the ACOS Lustre GST 801 at VE that might also help:
https://www.vinylengine.com/library/acos/lustre-gst-801.shtml

Thanks, I have read it, and actually am fortunate enough to have the original manual to the arm. So I suspect the magnetic VTF device is not functioning properly....but it would be nice to talk to someone who has hoof on experience with it.

Regards
Mister Pig

 

[fiddlefye]

That arm sure has all of the bells and whistles. I can't say as I've ever seen one "in the flesh" let alone had one to play with. I certainly wouldn't turn one down if it wandered in the door, mind you.

 

[KentTeffeteller]

No. this was their TOTL arm. As I understand it this was a Koshin design.

View attachment 991408 View attachment 991410

Regards
Mister Pig


Thanks, I have read it, and actually am fortunate enough to have the original manual to the arm. So I suspect the magnetic VTF device is not functioning properly....but it would be nice to talk to someone who has hoof on experience with it.

Regards
Mister Pig

Thanks for the superb explanation. So this ACOS' best tonearm. Wonder what is throwing off that adjustment. Do you have a lighter cartridge than the FR to try to verify the arm tracking force is working OK?

 

[sturgus]

I got some questions regarding the set up of tracking weight via the magnetic ring. There are a couple of things that need to be worked through. First of all, the counterweight must be the light version as it will not allow me to zero out this Fidelity Research cartridge. I added some weight to the back of the arm temporarily to be able to do so. This is with the VTF ring set at the 0 grams setting. Once that is done, as I understand it I am supposed to be able to move that VTF dial to the appropriate tracking force setting and be ready to go. When I do this, I do not get a change in tracking force. Have I misunderstood the process? I can set tracking force manually with the counterweight like a traditional tone arm, but I like to have things working like they are supposed to.

Anyone with any experience with this model of arm?

Regards
Mister Pig

You are missing the heavy counterweight that slides over the other counterweight. When you balance it with the weight you should be able to adjust the tracking force with the magnetic adjustment. Mr. Pig you have a very nice arm indeed. I have one and run my Paradox Denon 103 ,and my Koetsu Rosewood. It also has on the fly VTA. I hope you get it sorted out and working properly. Let us know.

 

[majick47]

Checked the GST-801 owners manual on VE, according to manual and chart re combined cartridge/headshell weight there are three tonearm counterwights to choose from. According to an owner on VE things have to be fairly precise for the magnetic system to work when matching the cartridge to the weights. Before you do anything else try a lighter cartridge.

 

[sfrost]

From the picture of the arm and table it seems like the arm is not mounted far enough back, arm looks to be fairly long and would need to be further from the spindle, could just be the angle of the photo.

 

[muovimies]

No experience but out of curiosity checked out the manual. Seems like a really nice arm, but by your description it does sound a lot like the magnetic tracking force isn't working. According to the manual it seems straightforward enough, set dial to 0, balance arm and start dialing, the counterweight should have nothing to do with it as long as you have enough mass back there to get it to balance. Is there absolutely no change no matter where the VTF dial is set? Maybe something in the mechanism has become stuck or the ring has become somehow loose, so that it doesn't rotate what ever it should be rotating but just spings by itself? If it's indeed broken, one would think it can't be a big thing, but getting there to fix it might be difficult. Just thinking out loud, hard to say much anything useful without ever seeing and operating one of those...

 

[Mister Pig]

Checked the GST-801 owners manual on VE, according to manual and chart re combined cartridge/headshell weight there are three tonearm counterwights to choose from. According to an owner on VE things have to be fairly precise for the magnetic system to work when matching the cartridge to the weights. Before you do anything else try a lighter cartridge.

I must not have come across that particular post regarding the weight ratio with the magnetic VTF feature. Would you happen to have a link to that particular post? Unfortunately the arm came with only one counterweight, and it looks to be the lightest one. The lowest weight cartridge I own is a Denon DL 304, and I am not sure that is going to be light enough as its a 7 gram cartridge.

I would love to acquire the additional counterweights for this arm, however, it looks like parts are scarce. On any given day there are tons of parts for your various SAEC and Audiocraft arms on Ebay. There is nothing for the GST 801 there. This is going to be a bit of needle in a haystack kind of search it looks like. In some ways the counterweights looks similar to the Denon ones. I wonder if one of them could be repurposed for this.

Thanks for the info, and hopefully I can get this worked out. It is a lovely arm.

Regards
Mister Pig

 

[Mister Pig]

From the picture of the arm and table it seems like the arm is not mounted far enough back, arm looks to be fairly long and would need to be further from the spindle, could just be the angle of the photo.

Tone arm is 240 mm in length, with an overhang of 15 mm, with a spindle to pivot of 225 mm. Measured it and its correct. Every indication is this is the arm that was originally installed in this VPI/Denon package.

Regards
Mister Pig

 

[Mister Pig]

Checked the GST-801 owners manual on VE, according to manual and chart re combined cartridge/headshell weight there are three tonearm counterwights to choose from. According to an owner on VE things have to be fairly precise for the magnetic system to work when matching the cartridge to the weights. Before you do anything else try a lighter cartridge.

This morning I doubled and tripled the mass added to the current counterweight I have, in order to keep it positioned in as far as possible. Did not have an effect on the magnetic VTF feature. So my guess is something is wrong there, even though the arm looks pristine. I suppose it doesn't matter as I can balance it like a conventional arm, I just tend to like things to work as they are intended to. I might have to get over that in this case. Or I start considering suitable replacements.

Regards
Mister Pig

 

[robbiesd]

Hello Mr. Pig,
I've got an opportunity to buy a Lustre GST 801. I can't seem to find enough info on it to determine if it would match up with a cart of 5.5 gr and a compliance of 20. (Stanton 681EEE) Might you have learned what the headshell weights? I don't see a figure for the arm mass anywhere and I see reference to headshell+ cart weight for selecting which counterweights to use. I don't want to buy it if won't match my cart.
Regards,
Robbie

 

[muovimies]

Hello Mr. Pig,
I've got an opportunity to buy a Lustre GST 801. I can't seem to find enough info on it to determine if it would match up with a cart of 5.5 gr and a compliance of 20. (Stanton 681EEE) Might you have learned what the headshell weights? I don't see a figure for the arm mass anywhere and I see reference to headshell+ cart weight for selecting which counterweights to use. I don't want to buy it if won't match my cart.

If it helps, in the technical specs it lists minimum cartridge weight (including headshell) as 13.5g. So with a 5.5g cartridge you could use a 8g headshell (including mounting hardware and leads). That would be as light as you can make the arm. It does seem the arm might be a bit on the heavy side of medium mass, but I believe with a headshell as light as you can get away with a cartridge of 20cu compliance probably should still work ok, but I'm only speculating. The good thing of S-shaped arms is they are pretty flexible.

 

[Mister Pig]

I read my manual this evening, and it does not give an effective mass of the arm. I did weigh the stock head shell on a scale, and it is 10 grams, while my Zupreme head shells are 12 grams. The arm tube is stainless, and there is an internal braid for shielding around tone arm wires. This arm was meant for moving coil cartridges of the 1980s, and they are low compliance offerings. I would consider this arm to be medium-high mass at very best, or perhaps lowish high mass. If this works well with higher compliance moving magnet cartridges, that I got no idea.

Regards
Mister Pig

 

[robbiesd]

I received the arm from Marc yesterday, you're right, it's a very nice piece of work. As a designer so to speak, I would have chrome plated the VTA adjusting arm instead of leaving it brass. With the receipt of it I can now start laying out the plinth, yea.

 

[Mister Pig]

I received the arm from Marc yesterday, you're right, it's a very nice piece of work. As a designer so to speak, I would have chrome plated the VTA adjusting arm instead of leaving it brass. With the receipt of it I can now start laying out the plinth, yea.

The adjusting arm on my VTA device is finished the same as the rest of the arm. It sounds like the seller had a new one machined. This part is removable, so perhaps it got lost, or the arm was incomplete at one time. In one of my photos you can see the arm VTA adjuster, its positioned near the Denon drive unit, its not a brass finish.

Regards
Mister Pig

 

[totem]

In one of my photos you can see the arm VTA adjuster

Were you able to work out your VTF issue?

 

[robbiesd]

The adjusting arm on my VTA device is finished the same as the rest of the arm. It sounds like the seller had a new one machined. This part is removable, so perhaps it got lost, or the arm was incomplete at one time. In one of my photos you can see the arm VTA adjuster, its positioned near the Denon drive unit, its not a brass finish.

Regards
Mister Pig

That could be. It would be odd for it to have not been originally chromed. Actually now that I look at it really closely, the backend is chromed, the VTA collar end where the threaded shaft is mated is chromed around the shaft also and the body appears to have been put up against a fine wire wheel or maybe some emory cloth and the threaded shaft is chromed or polished steel. But it works as it should, so no complaints.
Robbie