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stevieg69
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« Reply #15 on: August 11, 2015, 08:59:16 PM » |
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Hi was using Shure V15V,
but switched back to Stanton 881,
seems a bit better at shielding,i do however still have a wire from PTP$ plate screw to phonostage ground.
This is my only PTP type table and its a great design.
I am pretty sure the tonearm is isolated,it sits on a wood board.The screws that hold it on to slate go into threaded inserts epoxied into
blind holes.can't see a ground issue there unless the arm itself doesn't have internal ground.I was hoping to get that piece of mu metal by now to straddle that gap of the motor mounting plate and the big plate.
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stevieg69
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« Reply #16 on: August 11, 2015, 09:27:51 PM » |
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Wow,now I am really stumped.
I was tieing the tonearm ground wire together with the the PTP4 plate ground wire to the phono stage.
Just for the heck of it i untied them and only ran the PTP4 plate wire to the phonostage.
Its quieter and neither increases or decreases as the arm gets closer to spindle.
So basically the arm ground is not connected.That is strange.
What in the heck does this mean.
I AM REALLY STUMPED ON THIS>
Bad ground in arm?
Like i said because its slate these screws holding the plate are through holes.So i attached a wire on the underside where the screw and nut protrude.
I guess for mow I'll just use it like it is,its pretty quiet as it is.I couldn't begin to say why.
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stevieg69
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« Reply #17 on: August 11, 2015, 09:58:41 PM » |
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Right now its as quiet as a prostitute in church.
Peter since this is a PTP thing could you chime in?perhaps someone down the road will have
a similar issue.
1. Do you think i should at a later time rum a ground from a motor screw to top plate?
2.if that works I'll reconnect tonearm ground.
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niclaspa
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« Reply #18 on: August 12, 2015, 04:40:37 AM » |
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What you just did indicates that you have a ground loop and that it not a problem with insufficient shielding from the motor. I think that it is not bad ground in the arm and that you can solve the problem by connecting the ground wires in the right places. Safety ground (the ground in the mains plug) and signal ground must be treated different. The PTP4 top plate should be connected to safety ground only. There should be no connection between the top plate and the tonearm when all plugs are disconnected. The signal ground wire that comes out of the tonearm should be connected to the ground wire post on the phono stage:  This is a picture from another post that shows the wrong way to do it:  The yellow wire from the tonearm should not be connected to the top plate. It should be connected to the ground wire post on the phono stage only. |
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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reinderspeter
Administrator
Member
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Age: 61
Location: Amsterdam
Posts: 6,674
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« Reply #19 on: August 12, 2015, 08:10:58 AM » |
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Wow,now I am really stumped.
I was tieing the tonearm ground wire together with the the PTP4 plate ground wire to the phono stage.
Just for the heck of it i untied them and only ran the PTP4 plate wire to the phonostage.
PTP ground should not go to phonostage but to mains ground. Only the arm ground should go to your phono. |
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Peter PTP Audio for Lenco based idler drive Turntables, Chipamps and Power Controllers. |
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stevieg69
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« Reply #20 on: August 14, 2015, 04:08:11 PM » |
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Just for the heck of it I tried a cheater plug,and only tonearm ground goes to phonostage.
Seems like it works very well this way.Problem solved.Case closed
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stevieg69
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« Reply #21 on: August 14, 2015, 04:09:58 PM » |
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niclaspa
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« Reply #22 on: August 14, 2015, 05:28:50 PM » |
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Nice to hear that the problem is solved! When the hum is gone, are you happy with the sound?
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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stevieg69
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« Reply #23 on: August 15, 2015, 06:54:32 PM » |
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I expected more of the wow factor,didn't really get that.Next to the PTP one is one with the top plate epoxied in.
It holds its own against it.Thats just my experience.Of course I don't have a Graham tonearm or any superarm.
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niclaspa
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« Reply #24 on: August 16, 2015, 05:38:17 AM » |
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Pity that the new slate turntable did not impress! Obviously a better tonearm would give better sound, but if you have similar level tonearms/cartridges on the two turntables then it is a fair comparison.
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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stevieg69
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« Reply #25 on: August 16, 2015, 11:38:58 PM » |
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Update!!
redid wiring,also ran a wire from motor screw to top plate.
big improvement.Then changed out mat and tried out a NOS Pickering XSV-3000 w original stylus.
Mat is a Funk Firm acromat very highly regarded.
End result is very much in the WOW league.Its been a journey with these Lenco builds.
Sometimes i wish i had of just bit the bullet and bought Peters Solid 12 and been done with it.
Would have been cheaper in the long run.
Regarding this slate ptp4,i just knew it was capable of better.I wasn't gonna give up on it.
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niclaspa
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« Reply #26 on: August 17, 2015, 05:34:50 AM » |
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Nice to hear that it sounds better now!  Different mats can make a big change. Footers are also a way to tweak the sound. |
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Niclas
Ernst ist das Leben, heiter ist die Kunst
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