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PostPosted: February 7th, 2021, 1:39 pm 
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Brombo, Walt,

Yes, I have an ultrasonic humidifier running since Friday when I first observed the problem. Have to admit, it has been a week or more since I last listened to vinyl. Nothing in my setup changed.

I have everything grounded back to my preamp ground, which is itself grounded back to the earth ground via house wiring (i was using a ground binding post on a PS Audio power regenerator, but have just moved it over to my Tice via a ground wire plug from the preamp binding post to the socket ground. Both are grounded to the wall socket.

I measure the resistance from my turntable spindle and ground, and I get around 50 ohms. It really should be higher than that, but I uncovered a problem with the grounding wire on the Teres yesterday getting open circuit through the wire. I found one of the bolts underneath the turntable with 50 ohms resistance between the platter spindle and the bolt, so attached the wire to that. To reconnect the wire to the bearing housing, I would have to tear apart the entire turntable to access the connection. I am no doubt relying on an indirect pathway through the bolting to some point of conduction with the bearing. But 50 ohms SHOULD be as good as ground is for the potentials I am seeing. The copper mat is in contact with the spindle, and I measure the same resistance through the mat to ground. What is interesting is that I get a lot of static pull when lifting the record, a record that has been in direct contact with the copper platter mat. This is exceedingly odd.

The Teres controller is a hand assembled component, this is an artisanally built turntable, not a mass produced product. It has been working up to now (barring some motor bearing rattling problems that was fixed by re-lube.

Will continue to troubleshoot and try things to solve the problem, but it is frustrating and I have wasted most of my weekend trying to solve the issue. I tend to get intensely focused on a problem rather than walk away and come back later (usually when I walk away, the problem doesnt' get fixed until MUCH later.)

David


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PostPosted: February 7th, 2021, 1:46 pm 
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In the past I had a static problem with a turntable that had a dust cover. Solved it by putting some damp sponges inside the dust cover that kept the local humidity high enough to eliminate the static problem.


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PostPosted: February 7th, 2021, 2:11 pm 
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tomp wrote:
In the past I had a static problem with a turntable that had a dust cover. Solved it by putting some damp sponges inside the dust cover that kept the local humidity high enough to eliminate the static problem.


Tom,

No dustcover here. Actually, I wish I had a dustcover to help fend off one of my cats who sometimes gets fixated on the turntable. I tend to listen when he is distracted by other things (or asleep). But I have observed the static attraction that can occur with a dustcover in place with a lightly balanced tonearm.

David


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PostPosted: February 7th, 2021, 3:31 pm 
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Location: Parkville, Maryland
David McGown wrote:
tomp wrote:
In the past I had a static problem with a turntable that had a dust cover. Solved it by putting some damp sponges inside the dust cover that kept the local humidity high enough to eliminate the static problem.


Tom,

No dustcover here. Actually, I wish I had a dustcover to help fend off one of my cats who sometimes gets fixated on the turntable. I tend to listen when he is distracted by other things (or asleep). But I have observed the static attraction that can occur with a dustcover in place with a lightly balanced tonearm.

David

Rule one -- do not play records with the dust-cover in place -- it acts like a resonant chamber.

Rule two -- definitely use the dust cover when not in play -- it keeps things nice and clean.

No dust cover? Use a nice cotton cloth to cover the TT when not in play.

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PostPosted: February 7th, 2021, 3:40 pm 
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Actually a dust cover is a double edged sword. It definitely attenuates air borne vibrations but can couple them to the plinth. Then it depends how good your dust cover is insulated from the plinth and what the resonant frequency of the dust cover internal volume is and how that resonant frequency affects the tone arm/cartridge combo. That pretty much determines whether the dust cover is good or bad. Keeping the dust cover slightly elevated off the plinth also tends to kill the internal resonances in the dust cover internal volume. In my case the benefits definitely outweighed the drawbacks. Everyone's results will vary.


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PostPosted: February 7th, 2021, 9:50 pm 
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You could buy my Well Tempered Super with Reference arm, bearing and platter. Such a simple design, does not even have bearings... :lol: Virtually zero maintenance needed, will last forever. But I think there should be a solution for your existing setup....

Also, I do have an extra TD124 mkII that has rebuilt motor and bearing but it ain't super cheap. You could build your own plinth and armboards and have fun with it. They don't need much upkeep once they are fully sorted out but you do have to do some work to get them to that stage.


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PostPosted: February 8th, 2021, 12:02 am 
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Pete,

I might be interested in the TD124 so PM me about what you would consider letting it go for if you are serious about selling it. It is a table I always lusted over, particularly when I visited Schoppers in Winterthur, Switzerland many years ago, and I definitely could make a base, armboard, and anything else needed given a well functioning motor and bearing. I know you have some sunk cost in the table, so understand it will not be any bargain. Besides, I am a bit nervous about purchasing anything unseen from overseas (Japan) without really knowing the condition of the unit. Also realize that, although I can do a DIY recap, working on 40 year old phenolic circuit boards with the real possibility of lifting traces (all too easy to do), testing and replacing bad transistors, etc., may require a professional to do it right. So however tempting a $850 motor unit is from Japan, I have to factor in double that for a top restoration and basing (which I can do). PBNAudio is the place that does the Denon restorations, and they do a beautiful job of making custom new turntables from old motor units. Pretty impressive, though pricey.

That being said, I managed to stack up 3 VPI Magic Bricks from my turntable base so that I have a platform high enough to reach the platter and install an antistatic "dust bug" with a carbon fiber brush and grounding wire. Just performed a quick test and it seemed to reduce the static after playing one side. Ran out of time to play another side, so the real test is tomorrow. If it works, then fine. If not, try something else. Really strange this cropped up, I never had a problem like this previously, and I have put in hours long sessions listening with no problem.

David


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PostPosted: February 8th, 2021, 10:50 pm 
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Sometimes it is the simplest of things....

Turns out my 12V SLA battery, replaced only a year ago, could not keep a charge. Normally an SLA battery will last several years of use, so didn't even think it would be a problem. The Teres uses a smart charger that turns off the charger when playing a record so that the motor just runs on the battery. In the course of seeing if the anti-static brush solved the problem, the controller again flipped out 5 minutes into the second side of the record. I decided to disconnect the cable from the charger transformer, running purely on the battery. With a fully charged battery and low draw of the motor, one should be able to run 100 or so hours on battery power alone. Well, I noticed speed problems during playback. I checked the battery voltage as it was playing, and it was about 7.5 volts, pretty indicative of a bad battery. I had a new battery that I intended to put into a small UPS, so repurposed it for more noble use. Even fresh out of the package, it showed 13.5 volts. Turntable seems to be working fine now.

It makes perfect sense, the controller problems occured after a similar playing time, regardless of any attempts of static mitigation. The audible clicking sound I was hearing was likely the charger relay cycling on/off when the battery voltage reached the minimum threshold voltage.

So all is well. Thanks for putting up with my frustration and puzzlement. I did have fun considering some intreguing options for a backup turntable, seems I have gone through this hobby as a one turntable at a time guy. Of course with my current 80 lb+ turntable, swapping out is not easy, both in the moving off the stand and finding a place to sit it down. I am not convinced that I wouldn't get better sound if I had a restored classic turntable, and it is something I would really like to try as a project for fun, rather than necessity. So maybe I get that DP-80 after all and have some fun when I retire next year.

David


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PostPosted: February 9th, 2021, 10:31 am 
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Why would it be necessary to run a TT on battery power? One argument against it is exactly what happened to you.

A regulated DC power supply would be stable regardless of the line voltage and you would not have to worry about how many charge/discharge cycles the battery can tolerate.

????

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PostPosted: February 9th, 2021, 11:41 am 
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Agree with Walt. A good supply essentially isolates the circuit from the mains and to the circuit looks like an almost perfect battery.

Tom


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