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AR77XB questions

tinkerwalsh

tinkerwalsh

New Member
Hey everyone - few questions here. Pretty new to the good audio world.

I found an AR77XB in a old house I was working on. The owner gladly gave it to me. He figured it was junk.

I didnt know a whole lot about the AR77 but I dug the minimal look of it. It had a grounding issue. That has since been solved. I threw the old belt on it and started it up. First impressions its a GREAT sounding table. So Im stoaked. I was planning on buying a pretty expensive Thornes and Im glad I stumbled upon this thing.

anyway, questions are:

I checked the RPMs with my iphone (not sure how legit this is?) seems like it is running a little fast - 33.8 RPM. I orderd a new belt this morning. Anything else I should consider to aid in this?

The AR77 isnt as nice looking at the xa or xb. Im not ready to fully pull this thing apart and built a new plinth for it. I want to enjoy as is for awhile. The turntable has a kinda cheesy plastic bottom cover. Im wondering if i could just pull that off and throw some feet on it? Would it be fine to leave the bottom open? There a lot of options for turntable feet out there. Any recommendations?

It has a AT95E cart on it which sounds very good. I have a grado green that I was running on my pioneer pl-518. I have a feeling this AR will be my daily driver for a while. Would the grado green be a nice cart for it?

Lastly - the table doesn't have a dust cover. how hard is it to come by one of those?

Thanks for the thoughts!

Dave
 
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The XB77 (or 77 XB, as the label makes it look) is a bit of an odd duck, basically a bridge between the original XA/XB series and the later ES-1/"The Turntable". The arm is similar to the older AR turntables, though the headshell is different, and it uses a lighter counterweight to allow for use of higher compliance cartridges IIRC. The plastic base is indeed a bit cheesy, but unless you want to build a new wooden base for it, I'd leave it alone. With regards to the dust cover, eBay is your best bet; I'm not sure off-hand whether or not a dust cover meant for the XA/XB would fit the XB77.

With regards to platter speed, I'm not sure why it'd be running fast, as the only things governing it are the motor, line frequency, and belt (and an issue with that would likely be making it run too slow, not too fast). You may want to try replacing the motor capacitor with one of the same value, though I don't think it has much of an effect on its speed. Check the motor pulley and the edge of the small subplatter for gunk, which may be the sign of a failing belt, and clean them using rubbing alcohol if they're dirty. Lastly, be sure to coat the replacement belt in talcum powder before installing it, as the motor relies on a bit of 'slip' in order to get the platter moving. Good luck!
-Adam
 
AdamAnt316 said:
The XB77 (or 77 XB, as the label makes it look) is a bit of an odd duck, basically a bridge between the original XA/XB series and the later ES-1/"The Turntable". The arm is similar to the older AR turntables, though the headshell is different, and it uses a lighter counterweight to allow for use of higher compliance cartridges IIRC. The plastic base is indeed a bit cheesy, but unless you want to build a new wooden base for it, I'd leave it alone. With regards to the dust cover, eBay is your best bet; I'm not sure off-hand whether or not a dust cover meant for the XA/XB would fit the XB77.

With regards to platter speed, I'm not sure why it'd be running fast, as the only things governing it are the motor, line frequency, and belt (and an issue with that would likely be making it run too slow, not too fast). You may want to try replacing the motor capacitor with one of the same value, though I don't think it has much of an effect on its speed. Check the motor pulley and the edge of the small subplatter for gunk, which may be the sign of a failing belt, and clean them using rubbing alcohol if they're dirty. Lastly, be sure to coat the replacement belt in talcum powder before installing it, as the motor relies on a bit of 'slip' in order to get the platter moving. Good luck!
-Adam
Click to expand...

belt thickness will affect speed. too thick, and it will run fast. A loose, "dry" belt will also make it run fast, until it gets too loose and wants to fall off. of course a dirty pulley will make fast due to the diameter is bigger due to dirt.
 
marcmorin said:
belt thickness will affect speed. too thick, and it will run fast. A loose, "dry" belt will also make it run fast, until it gets too loose and wants to fall off. of course a dirty pulley will make fast due to the diameter is bigger due to dirt.
Click to expand...
Interesting. Most of the experience I've had with too-thick rubber belts involved them bogging down the works, causing the platter to run slower than it should. Granted, that was with an RCA Selectavision CED player, which is a fair bit removed from the average turntable technology-wise, so that might have had something to do with it. Anyway, assuming the XB77 the OP is referring to is still equipped with an older belt, I can't imagine one getting tighter over time, though it drying out is definitely a possibility.
-Adam
 
AdamAnt316 said:
Interesting. Most of the experience I've had with too-thick rubber belts involved them bogging down the works, causing the platter to run slower than it should. Granted, that was with an RCA Selectavision CED player, which is a fair bit removed from the average turntable technology-wise, so that might have had something to do with it. Anyway, assuming the XB77 the OP is referring to is still equipped with an older belt, I can't imagine one getting tighter over time, though it drying out is definitely a possibility.
-Adam
Click to expand...
by "dry" i was referring to no talc. that makes the belt momentarily static to the pulley surface during latch of the motor. The belt needs to be in a constant state of slippage on the pulley to average the pulley surface velocity.
 
excellent! thanks for the replies everyone. I will pick up some talc tomorrow. hopefully the belt i ordered is the correct thickness. looking forwards to hearing the grado on it. loving the ar!
 
tinkerwalsh said:
The turntable has a kinda cheesy plastic bottom cover. Im wondering if i could just pull that off and throw some feet on it?
Click to expand...

I did exactly that with mine.
It has 2"x1" feet of unknown origin. Nothing special.
Looks a whole lot cooler than you might think even with the tacky vinyl trim.
In fact, I like the proportions so much, if I were to make a new plinth I'd use the same dimensions as the old one.

To add feet you'll probably have to glue extra wood in the corners....which may or may not mean relocating stuff underneath.
Honestly, it's been so long ago [20 years] that I modded mine that I forget what was involved.

My daily driver. Regularly gets a much harder workout than my Technics SL-1200.
I keep the suspension stiffer than most suggest. Has a high-torque Hurst replacement motor.
Basically an old man's version of a DJ deck. I use it to play 45's.
Love that table. I'm always on the look-out for another.
 
On my AR XA I went with just three feet, two up front corners and one along the back middle. Much easier to
level with three feet.

Nashou
 
45rpmspinner said:
I did exactly that with mine.
It has 2"x1" feet of unknown origin. Nothing special.
Looks a whole lot cooler than you might think even with the tacky vinyl trim.
In fact, I like the proportions so much, if I were to make a new plinth I'd use the same dimensions as the old one.

To add feet you'll probably have to glue extra wood in the corners....which may or may not mean relocating stuff underneath.
Honestly, it's been so long ago [20 years] that I modded mine that I forget what was involved.

My daily driver. Regularly gets a much harder workout than my Technics SL-1200.
I keep the suspension stiffer than most suggest. Has a high-torque Hurst replacement motor.
Basically an old man's version of a DJ deck. I use it to play 45's.
Love that table. I'm always on the look-out for another.
Click to expand...

Nashou66 said:
On my AR XA I went with just three feet, two up front corners and one along the back middle. Much easier to
level with three feet.

Nashou
Click to expand...

Awesome! I just ordered some feet for the AR! Loving the table so much. My poor old Pioneer isnt getting much use.

Any other upgrade I should consider in the future?

best,

DFW
 
Nashou66 said:
On my AR XA I went with just three feet, two up front corners and one along the back middle. Much easier to
level with three feet.

Nashou
Click to expand...
I'd tend to stick with using four feet, myself, since three feet tend to make things a bit more tipsy than I'd like. I used Audio-Technica AT-605 audio insulator feet with my AR XB, as seen below:
arxb.jpg
 
marcmorin said:
you're adding in a different spring rate into the system.
Click to expand...
The main idea was to counteract the XB's internal spring suspension to some degree. The stereo cabinet the AR XB was sitting on stands on a wooden floor, so any nearby movement caused the tonearm to go skipping around the record. Not sure that the A-T feet helped or hurt much, frankly, but I didn't notice things being any worse than they'd been before I added them.
-Adam
 
johnjhazel said:
I bought this dust cover for my mint AR 77-XB:
https://www.ebay.com/itm/Acoustic-R...300716?hash=item2a789ed1ac:g:seMAAOSwYL9Z1BEE

I am also using a Rega 3mm thick wool platter mat. Sounds excellent.
Click to expand...

Thanks for the link! The dust cover is almost $300 to ship to canada ;(

Also good to know about the Rega mat. Ill check it out!

I currently have a cork/plastic/rubber mat on there. It sounds really good! I got a little concerned there might be too much weight on the suspension? The table functions great with it on there.
 
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