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My (new) AR SUPER XA!

tygr

tygr

Audiophoole
Thanks to Marc Morin, my AR XA is a super table now. He rebuilt the tonearm with new bearings and surfaces, micro polished where necessary, replaced the wand with an SL 1200 model for greater headshell selectivity, and it tracks beautifully! I also got a set of heavy duty springs and Marc's own mass ballast kit and this thing is a new table! I love it!

OK, I just had to gush a little.
 
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OK, pics:
 

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Straight from the ad:


The DM-2310 White Perspex Acrylic turntable mat will provide a fresh modern look, improved mid-range, tighter bass response and a less splashy sound. Suitable for all turntables with 12" platter. 2.0mm thick. There is a 0.5mm record Label recess in the center ensuring records will sit perfectly flat.


FEATURES

Provides fresh modern look.
Improves mid-range.
Provides tighter bass response.
Less splashy sound.
0.5mm record label recess in the center.
 
tygr said:
Thanks to Marc Morin, my AR XA is a super table now. He rebuilt the tonearm with new bearings and surfaces, micro polished where necessary, replaced the wand with an SL 1200 model for greater headshell selectivity, and it tracks beautifully! I also got a set of heavy duty springs and Marc's own mass ballast kit and this thing is a new table! I love it!

OK, I just had to gush a little.
Click to expand...


Congrats on a beautiful table.

So what is the deal with the spring and mass kit? What does it do? Is it to dampen unwanted resonances?

Can you describe the sound difference?

Thanks, Bob
 
Marc will help you with all of your AR turntable needs. From mild to wild, Marc is your go to guy.
 
bobins08 said:
Congrats on a beautiful table.

So what is the deal with the spring and mass kit? What does it do? Is it to dampen unwanted resonances?

Can you describe the sound difference?

Thanks, Bob
Click to expand...

Hi Bob, Going to the Linn springs, the suspended mass has to be increased by 3-3 1/2 pounds. If not, the spring resonate frequency will be very high. It needs to be in the 3.2 - 3.7hz range. Where I add the mass now is via a downrigger system. This puts the added mass equal distance down from the top of the spring as the subchassis and platters are above the top of the spring. The "want to topple" of the suspension from any input is greatly reduced. Any movement of the springs other than to filter in a purely pistonic fashion affects speed stability. The mass is distributed in a fashion that keeps the natural center of gravity, and is set so all three springs are seeing equal mass, and compression. Tuning to ride height alone gets the system to near perfect tune. Adjusting the spring spine is all that is left. Which brings us to the spring mounting system. The lower spring perches, upper grommets, and grommet locators force the spring to be square to the studs at all times removing most of the "spine effects" of the spring.
 
tygr said:
Straight from the ad:


The DM-2310 White Perspex Acrylic turntable mat will provide a fresh modern look, improved mid-range, tighter bass response and a less splashy sound. Suitable for all turntables with 12" platter. 2.0mm thick. There is a 0.5mm record Label recess in the center ensuring records will sit perfectly flat.


FEATURES

Provides fresh modern look.
Improves mid-range.
Provides tighter bass response.
Less splashy sound.
0.5mm record label recess in the center.
Click to expand...

I use the same mat...works great on the AR, as well as my Scoutmaster II.
 
marcmorin said:
Hi Bob, Going to the Linn springs, the suspended mass has to be increased by 3-3 1/2 pounds. If not, the spring resonate frequency will be very high. It needs to be in the 3.2 - 3.7hz range. Where I add the mass now is via a downrigger system. This puts the added mass equal distance down from the top of the spring as the subchassis and platters are above the top of the spring. The "want to topple" of the suspension from any input is greatly reduced. Any movement of the springs other than to filter in a purely pistonic fashion affects speed stability. The mass is distributed in a fashion that keeps the natural center of gravity, and is set so all three springs are seeing equal mass, and compression. Tuning to ride height alone gets the system to near perfect tune. Adjusting the spring spine is all that is left. Which brings us to the spring mounting system. The lower spring perches, upper grommets, and grommet locators force the spring to be square to the studs at all times removing most of the "spine effects" of the spring.
Click to expand...


When you say "tuning to ride height" is there a specific distance from the top plate to the bottom of the platter that puts it in spec? Seems like that would be a function of spring quality?

So you basically made a mod to use the Linn springs to improve the suspension.

thanks, Bob
 
bobins08 said:
When you say "tuning to ride height" is there a specific distance from the top plate to the bottom of the platter that puts it in spec? Seems like that would be a function of spring quality?

So you basically made a mod to use the Linn springs to improve the suspension.

thanks, Bob
Click to expand...

Tuning to ride height, ie level, has all three spring under equal compression height. A springs resonate frequency is a function of load and compression.
If all three springs aren't compressed equally, all three springs will have their own frequency. Normally that's quite counter productive. Although a brand that requires indepth knowlege of the "black arts" seems to get away with that.
 
Marc, I know you have been enthusiastic about deerskin mats for a long time. Is this white perspex mat something that came from your shop, and therefore you are now preferring it to the deerskin, or was it sourced elsewhere?
 
Barncats said:
Marc, I know you have been enthusiastic about deerskin mats for a long time. Is this white perspex mat something that came from your shop, and therefore you are now preferring it to the deerskin, or was it sourced elsewhere?
Click to expand...

Sourced elswhere. I still prefer deerhide.
 
Oops, that misunderstanding would be my fault. Marc in no way influenced me to try the Perspex mat. I found them on that auction site.
 
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