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Thorens and grado

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Thorens and grado

Postby andrewcroft2006 » 23 Sep 2017 21:43

Hi everyone I hope you can help I have a Thorens td318 and am interested in Grado gold cartridge but am concerned about the problem of grado hum would this be a problem on this turntable thanks in advance for any help.
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Re: Thorens and grado

Postby doctor fuse » 13 Oct 2017 08:55

Hi Andrew,

Right before I scored my TD160, I had bought a 8MZ stylus for my Grado X-3F cartridge (it sounded stunning on my Technics belt drive). I was very disappointed that it hummed like a soprano who had forgot the words.

I can't understand why many folks on these fora talk about how their Grados don't hum on their old Thorens with AC motors. Maybe they just listen at whisper-thin levels?
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Re: Thorens and grado

Postby cement_head » 22 Oct 2017 13:49

I have a Grado Prestige Gold II on my TD 50 MKII A/B and it sounds awesome - very nice with the table. On my second stylus! No hum. If you have hum, you may have an earthing problem.
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Re: Thorens and grado

Postby mgomez » 27 Oct 2017 01:52

Hello,
I have a tp90 long
I would like to mount my Grado wood body reference series
Does any one know the details on the TP 90 alignment tool (I have one but the manual is not clear on how to use it)
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Re: Thorens and grado

Postby tlscapital » 27 Oct 2017 08:16

cement_head wrote:I have a Grado Prestige Gold II on my TD 50 MKII A/B and it sounds awesome - very nice with the table. On my second stylus! No hum. If you have hum, you may have an earthing problem.


I don't know the Grado cartridges per say, but I would doubt that a good cartridge like that would induce such issues on it's own or through a bad or wrong build. I know the recurrent say I don't hear it so it doesn't exist meaning refusing to hear it. But here I want to second the ground or loop lead on the issue.

My Denon DL-102 MC cartridges is very magnetic and I did had hum at times through the evolution of my tweaks on my previously tweaked Thorens not by me. Mind that my phono set-up sound got "cleared" out and the hum became more noticeable through my tweaks improvements.

Firstly I understood that I have to have a a good dampening mat layer on the alloy platter to prevent my "magnetic" cartridge to challenge the gravity VTF ! Since I got rid of the original rubber thick Thorens mat I had to gradually replace it with my now perfectly fit for my use and efficiency with my "lasagna" mat !

Finally I did a dedicated tonearm wand ground. Previously the sub-chassis and chassis ground was linked to the tonearm ground. Likely the platter/cartridge magnetism induced that hum loop... Since those platter matt dampening and split dedicated grounds I have pure silent speakers. A joy !
tweaked Thorens TD145+'Eagle & RoadRunner'
4 mats; LP vinyl topped with felt+cork+leather
SME 3009 'Imp' converted to heavy mass
Denon DL-102 in Ortofon bakelite SPU
Isem 'Modulis'+Etalon 'Exampli'
12" Leak 2 ways 'Sandwich' 15 OHMS
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Re: Thorens and grado

Postby cafe latte » 27 Oct 2017 08:40

tlscapital wrote:
cement_head wrote:I have a Grado Prestige Gold II on my TD 50 MKII A/B and it sounds awesome - very nice with the table. On my second stylus! No hum. If you have hum, you may have an earthing problem.


I don't know the Grado cartridges per say, but I would doubt that a good cartridge like that would induce such issues on it's own or through a bad or wrong build. I know the recurrent say I don't hear it so it doesn't exist meaning refusing to hear it. But here I want to second the ground or loop lead on the issue.

My Denon DL-102 MC cartridges is very magnetic and I did had hum at times through the evolution of my tweaks on my previously tweaked Thorens not by me. Mind that my phono set-up sound got "cleared" out and the hum became more noticeable through my tweaks improvements.

Firstly I understood that I have to have a a good dampening mat layer on the alloy platter to prevent my "magnetic" cartridge to challenge the gravity VTF ! Since I got rid of the original rubber thick Thorens mat I had to gradually replace it with my now perfectly fit for my use and efficiency with my "lasagna" mat !

Finally I did a dedicated tonearm wand ground. Previously the sub-chassis and chassis ground was linked to the tonearm ground. Likely the platter/cartridge magnetism induced that hum loop... Since those platter matt dampening and split dedicated grounds I have pure silent speakers. A joy !

Grado are unshielded and they do hum with ac motor turntables if the motor does not have em shielding ie a steel shroud. Hard to do though as EM flows like water. My Commonwealth has a shield that works it is like a large food can sitting over the motor like a hat. If motor is on side like a Lenco hard to do as EM flows out the end, but upright like Commonwealth shield works perfectly for Decca and grado (both unshielded carts).
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Re: Thorens and grado

Postby tlscapital » 27 Oct 2017 19:31

The Thorens TD318 has a 16 volts AC motor. So unlike the 110/220 volts one would it still generate so much EMF (electro-magnetic frequencies) to induce hum to an "unshielded" cartridge ? I don't know so I'm only asking.
tweaked Thorens TD145+'Eagle & RoadRunner'
4 mats; LP vinyl topped with felt+cork+leather
SME 3009 'Imp' converted to heavy mass
Denon DL-102 in Ortofon bakelite SPU
Isem 'Modulis'+Etalon 'Exampli'
12" Leak 2 ways 'Sandwich' 15 OHMS
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Re: Thorens and grado

Postby cafe latte » 28 Oct 2017 02:41

tlscapital wrote:The Thorens TD318 has a 16 volts AC motor. So unlike the 110/220 volts one would it still generate so much EMF (electro-magnetic frequencies) to induce hum to an "unshielded" cartridge ? I don't know so I'm only asking.

Then there must be a step down transformer in the plinth too which will be producing EM fields just the same as the motor. Shielding the transformer though should be easy. I would have though that field strength would be dependant on the power of the motor too and a lot will depend on if it is a shielded design too and if not how easy it is to shield. Have a look at my Commonwealth restoration thread as there is a pic there of the EM shield and it works perfectly.
Chris
edit..
viewtopic.php?f=18&t=34547
Second pic first post..
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Re: Thorens and grado

Postby tlscapital » 28 Oct 2017 09:54

hum
andrewcroft2006 wrote:Hi everyone I hope you can help I have a Thorens td318 and am interested in Grado gold cartridge but am concerned about the problem of grado hum would this be a problem on this turntable thanks in advance for any help.


So since you motor runs at 16 Volts and your external wall wart step down transformer can be placed far away from the turntable, any EMF from the AC motor should be minimalistic.

Inducing maybe only a little hum. If ever the hum is still too present, one can maybe apply a DIY lead (soft to cut, bend and shape and most efficient to block EMF) motor shield.
tweaked Thorens TD145+'Eagle & RoadRunner'
4 mats; LP vinyl topped with felt+cork+leather
SME 3009 'Imp' converted to heavy mass
Denon DL-102 in Ortofon bakelite SPU
Isem 'Modulis'+Etalon 'Exampli'
12" Leak 2 ways 'Sandwich' 15 OHMS
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Re: Thorens and grado

Postby cafe latte » 28 Oct 2017 13:32

tlscapital wrote:hum
andrewcroft2006 wrote:Hi everyone I hope you can help I have a Thorens td318 and am interested in Grado gold cartridge but am concerned about the problem of grado hum would this be a problem on this turntable thanks in advance for any help.


So since you motor runs at 16 Volts and your external wall wart step down transformer can be placed far away from the turntable, any EMF from the AC motor should be minimalistic.

Inducing maybe only a little hum. If ever the hum is still too present, one can maybe apply a DIY lead (soft to cut, bend and shape and most efficient to block EMF) motor shield.

Is the transformer not inside the plinth?
Chris
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Re: Thorens and grado

Postby tlscapital » 28 Oct 2017 13:45

cafe latte wrote:Is the transformer not inside the plinth?
Chris


No, on the Thorens it's an external wall wart type transformer.
tweaked Thorens TD145+'Eagle & RoadRunner'
4 mats; LP vinyl topped with felt+cork+leather
SME 3009 'Imp' converted to heavy mass
Denon DL-102 in Ortofon bakelite SPU
Isem 'Modulis'+Etalon 'Exampli'
12" Leak 2 ways 'Sandwich' 15 OHMS
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Re: Thorens and grado

Postby andrewcroft2006 » 06 Nov 2017 21:18

Thanks all for your replys i can confirm the td318 has a wall wart so i asume this will reduce the chance of hum with grado cartridges, cant decide wether to go with grado or nagaoka the grado gold is within my price range nagaoka mp150 also.
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Re: Thorens and grado

Postby Kurt45 » 06 Nov 2017 21:51

I have a Grado Signature Jr on my Thorens TD316 (manual version of the 318) and I don't have any problems with hum.

I have a Grado Blue on my Technics SL-7, and that does have a slight hum.
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Re: Thorens and grado

Postby doctor fuse » 07 Nov 2017 02:28

Kurt45 wrote:I have a Grado Signature Jr on my Thorens TD316 (manual version of the 318) and I don't have any problems with hum.

I have a Grado Blue on my Technics SL-7, and that does have a slight hum.


Is the Signature a low-output? Do LOs not hum like the HOs (Hos that "hum"....hmmmm? :lol: )?

My XF-3 and 8MZ/Green hum only very slightly on my Technics. You are talking very minimal hum, aren't you?
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Re: Thorens and grado

Postby Kurt45 » 07 Nov 2017 05:14

doctor fuse wrote:
Is the Signature a low-output? Do LOs not hum like the HOs (Hos that "hum"....hmmmm? :lol: )?

My XF-3 and 8MZ/Green hum only very slightly on my Technics. You are talking very minimal hum, aren't you?


Signature Jr. I believe was 3.5mV, so not low output. The higher models in the Signature line had a 1.5 mV output -- is that what you're thinking of?

The hum on the Blue is minimal; I'm living happily with it, though it does grow more noticeable as the arm nears the centers of the record.
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