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AR-XA/other - Marc Morin tips, hints, instruction?

Dale Murray said:
I just picked up an AR-XA and researching what I should do with it to get it up to snuff and it appears Marc Morin was a highly respected authority on AR equipment. I never heard of him until yesterday and I already know what an influence he had here.

Has anybody created a library of Marc Morin information?
His tips, tricks, sources, etc?

The table I purchased is 100% bone stock and I know the basics of cleaning, lubrication, etc. What I would like to find is information on springs, adding weight, etc.

I would also like to find a add tone are queue lever instead of dropping the needle manually.

I discovered the official AR Owners thread and on page 4 of it at the moment. I do intend to read through it, however.
Click to expand...
Just picked up a AR XA Monday. Will need plenty of TLC.

238847496_4525808480763718_4395094662906729567_n.jpg
 
Finally got back to working on mine.
Whats been done:
- machined new liner for platter well.
- replaced delrin in both t-bar wells.
- polished bearing at bottom of spindle.
- replaced wand with Technics wand using audio-technica headshell.
- replaced motor, capacitor, etc.
- replaced tonearm pivots.
- made new plinth (spalted maple and rosewood)

Issues:
Need to know what values to use for protractor when using Technics wand.
Need guidance on grounding
  • currently I have tonearm, cartridge, & t-bar connected to star ground, star ground attaches to L&R RCA jacks
Power on, I hear a pop through the speakers.
Power off, I head a pop through the speakers.
When powered on, and not playing I hear a very faint crackling through speakers.
I imagine I need to rework the grounding.
 
Dale Murray said:
Issues:
Power on, I hear a pop through the speakers.
Power off, I head a pop through the speakers.
Click to expand...

Try a suitable high voltage AC mains-rated capacitor (e.g. X2-type, or a high voltage ceramic) of about 0.01µF across the switch terminals, which should eliminate the switch-on/ switch-off clicks/pops.

They're used in many Japanese turntables, and more than a few amplifiers, including the first one I ever built in the 1970's, of which the only remaining original parts are the nice case, knobs, switches, input terminals and on/off capacitor, but it still doesn't click at switch-on. It has a 1000V ceramic capacitor across the power switch.
 
I have this table mostly sorted, I'd like to think.

Outstanding issues:
  • Still need to install cap across power switch terminals.

New issues:
  • When I start it I hear a buzz like the motor struggling but that should not be the case; new motor and cap, the platter spins VERY smoothly.
  • susceptible to skipping from walking around, Neither BIC 980 or ATLP120 had this issue on this same cabinet in this same house in this same place.
    • The suspension is free floating with a roughly 3 hertz resonance.
    • The platter is balances at 1/8" above the metal top.
    • I can tap on the plinth very hard with zero issues.
    • I can tap on the stereo stand without issues.
    • Walk near it and it seems to easily skip.
    • Tracking force is 2 grams.
    • Original springs, no added weights, etc.
We do not stomp around the house.
It seems if the disturbance is rising up from the floor causes issues.

I am not opposed to building a proper isolation platform - and actual suspension of some sort, not a slab of wood.

Photo in its current state.
I am not terribly pleased with the dustcover I made; I intend to make another one sometime.
Hinges not installed.
 

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The Haydon motor is weak but it may be part of the special mix that makes the early ARs sound so good. I don’t know. I have to give my platter a spin or it simply won’t start. Once it’s to speed all is well.

Regarding skipping from footfalls, you might need to put it on a wall mount. Mine is in the corner of the house on a heavy credenza. Short of wall mount, I have had luck using a standard stereo rack with the rear spikes removed and wood blocks wedged in the top against the wall.

Keep at it because I’ve had ‘better’ turntables and prefer the XA.
 
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