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How can I tell if my EMT is 927 DST or just 927 ST

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How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 05 May 2012 08:39

Hi,
I bought EMT 927 several months ago and I finally managed to make it play. I had Hz problem because here the Hz is 60 and my EMT is 50 Hz version.
I solved the problem using Hz converter. The converter output is 100 V and 117 V only and I had to rewire to make the turntable for 100V.
Now it turns with proper speed. The sound is pretty good. Above all things, I could feel the sound played by the turntable was stable and neutral. This was very different feeling from what I had from Thorens 124 or Garrard 301.

Last night, while I was listening to the music, I found the speed is strange and saw the motor was shaking itself from time to time. It wasn't normal minor vibration of the motor which all the big motor has. Usually it turned quitely with small vibration which I think is normal. But it was sudden spasmodic trembling.

I switched off the turn and checked if any thing wrong with power connection but I couldn't find anything strange.

Has anybody experienced this kind problem? I cannot imagine what is going on with this turn #-o If you have any idea, please let me share your knowledge.

Another thing I want to ask....... :roll:
Since I got this turntable I read any information which is available on the net and found it might be DST version not usual ST. But I am not sure. Is there specific characteristic from which you can tell what is what?
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby J.D. » 05 May 2012 21:17

What a stunner of a thread, there, Mosin. I've only read thru page one and it's already addictive. Perfect audiophile aspirational reading -- can't think of many of us that wouldn't like to have the problem of the OP there (ie, two 927s to restore).

(Just now wondering if they'll get to that 'greymatter' platter material or whatever it was-- that Schopper used for its aftermarket/ replacement td124 nonmagnetic platter... ) Guess I'll just have to get back to the twenty-two pages remaining so I can find out .... Thanks very much for posting that one.

musicomm: don't be afraid of sending Stefano Pasini a polite email to inquire about the intricacies of the Emt. He's a sure source of good info.
http://www.stefanopasini.it/

Good luck,
JD.
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 05 May 2012 23:49

Thank you guys
I think I am going to contact Stefano and get some opinion.
Analogue is not easy!! :lol:
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby mosin » 06 May 2012 00:07

FYI, JD

That 'greymatter' platter material is more than likely austenitic cast iron. It is only slightly magnetic due to the high amount of nickel content. (I reverse engineered it.) There are at least seven different alloys in the austenitic cast iron class, but only one that is suitable for a turntable platter, in my opinion. ;)

More information than you ever want to know, if that wasn't:

The smallest heat of the iron that you can have poured is 800lbs., and it will be priced according to the current selling price of the materials on the commodities exchange. Anything less than 800 lbs. will damage the typical furnace used in today's mini mills. That's a lot of platters!

Right now, nickel is through the roof, so the price of a finished platter is probably a bargain because of the number they most likely have in stock due to the required weight of the pour. Expect the next batch of them to be higher priced, especially if they use an alloy that they tweaked by adding even more nickel or other non-magnetic content.

--- The EMT 927 has a 12.5 lb. cast aluminum platter.
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby J.D. » 06 May 2012 05:20

There goes my plan of casting a cutting-edge austenitic-iron tonearm.

Oh well, another day, another flagship High-end innovation down the drain.

You should have seen the counterweight.

J.
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby Blue Angel » 06 May 2012 10:47

mosin wrote:FYI, JD

That 'greymatter' platter material is more than likely austenitic cast iron. It is only slightly magnetic due to the high amount of nickel content. (I reverse engineered it.) There are at least seven different alloys in the austenitic cast iron class, but only one that is suitable for a turntable platter, in my opinion. ;)

More information than you ever want to know, if that wasn't:

The smallest heat of the iron that you can have poured is 800lbs., and it will be priced according to the current selling price of the materials on the commodities exchange. Anything less than 800 lbs. will damage the typical furnace used in today's mini mills. That's a lot of platters!

Right now, nickel is through the roof, so the price of a finished platter is probably a bargain because of the number they most likely have in stock due to the required weight of the pour. Expect the next batch of them to be higher priced, especially if they use an alloy that they tweaked by adding even more nickel or other non-magnetic content.

--- The EMT 927 has a 12.5 lb. cast aluminum platter.


I bought a 12mm thick plate of pure nickel weighing about 6kg 12 years ago and still have it. Maybe I can sell it and go fishing? :lol:

ba
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 06 May 2012 15:52

I think my turn is 927D.
There are several things which are different from ST version. Confusing thing is the body is marked as 927ST and all other things which my turn has tells me it is special D version.
First, the plate marked as 927D. (927D is a mono version of 927DST). And. the the mat is glass. And the pole, I don't know how to call it, for LP location in the center of the turntable, has shape of cone and has spring so the LP stops before it touchs the glass mat and you need to puch the LP down to the mat by stabilizer. And the quick start switch is blocked by a piece of steel plate.
I am adding some pictures. Please see those pictures and let me hear your opinion.

Hmm...How do you upload pictures?????
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 06 May 2012 16:04

another pic
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 06 May 2012 16:06

one more pic
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 06 May 2012 16:09

markj on the body
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby jloveys » 06 May 2012 20:52

Hi Kim, you have a very rare 927 D version of the 927st . The "D" means that it has a glass auxiliary platter (Glassmat ) , a special glass-rubber mat that replaced the standard acrylic mat . The "st" means that the power supply is made for the 139 stereo phono equalizer. The lighter acrylic mat ( 927 A ) has a felt brake to allow instant start/stop for broadcast use. With the glass auxiliary platter the clutch system can't be used but it is not a problem in domestic use.
Some 927 users say that the glass mat sounds better, some others say it makes no difference.
EMT 927 restoration is a real dedication and only a few experts have the knowledge and experience to make them work as intended by the factory 40 years ago…so my advice is to contact one of them.
My double 927 restoration project is made by Hans Van Vliet in Holland , you can contact him about your motor trouble, he will tell you the best thing to do.

Jean
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 07 May 2012 00:48

Hi, Jean,Thank you for the answer.
I am learning everyday about the turn, EMT 927. :D . And I am delight to learn that my turn is one of the rarest.
It is fascinating to study about the legend with the real right next you. Anyway congratulation of your project which is near to completion. Your heart must run very fast these days for the result. And one of the best thing here is to take time and try to complete as perfect as possible.

I asked to my friend who has many German machines (and the platters^^. He said he has an motor too :mrgreen: . He has 927, R82,and R37-I haven't seen R37 yet) about my turn problem and his opinion was that the capacitor for the motor start might be the problem. So I am looking for the same or substitute - 3mf Frako . How is your motor anyway? Has the speed steady? Run quitely? Is there any need to change any part from power supply?

How about the tonearm? I am thinking to install re-make 997 because original is not easy to find and quite expensive. I haven't used that but it looked quite good to me and I couldn't tell if that was replica or original. (930 with 997 replica)


Kim
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 07 May 2012 05:46

Hi,
I am thinking to change the cap which is for the motor start, I believe.
It is marked as Frako and 3uf.
I couldn't find the same one yet but found some similiar ones.

For example this one has 5uF instead of 3. Do you think this will work with 927 motor?

http://www.ebay.de/itm/56x-Motor-Konden ... 4178wt_905

And there is another which is made by same company Froko and similiar number to 3uF but used.

http://www.ebay.de/itm/2-x-Kondensatore ... 578wt_1344

Should the cap have the same capacity or will it be ok to use those one?

Kim
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby Stefano » 07 May 2012 08:31

Dear friends,

I answer to this user in the Forum, as he posted this question here before sending me (and others, I guess....) a private mail that is simply a copy-and-paste of this message.

I don't know what has been 'wired' to convert the frequency to use this 927 at home: if it is an 'inverter' :evil: , why are the capacitors still there? Anyway changing them is easy, a pack of original replacements are available from the German EMT specialists.

IMHO, I have no certainty that this is a genuine 927D. The centre spindle is not what I had on mine (the original one is quite 'thin', 5 mm to allow for a precise centering of the vynil grooves: see a similar item fitted on a 927F at http://www.stefanopasini.it/EMT_index_927.htm ) and this can be fitted on any 927, as the glass platter. The screwed-on chassis plate means little or nothing to us, as the number of this pre-1961 machine is not listed in today's EMT archives. The only original engraving is '927st'.

Looking at the pics give me some more food for thought. Fitting a non-original tonearm, intead of its original Ortofon (the ONLY tonearm for this series of 927), compromises quite seriously the sound quality of what could be a great turntable. Moreover, using it as it rests on its lower metal 'utility' frame furtherly degrades its sound: the instructions for every idler-wheel EMT recommends suspending it in an appropriate custom-made console, resting on four rubber corners provided under the four corners of the main (grey) chassis. :roll: I suspect that this 927st, in the present conditions, sounds more or less like a 938, and surely not better than a good 124.

I would be very curious to see what a R37 is, and there is NO 'R82'.... [-X

Kind regards

Stefano
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Re: How can I tell if my EMT is 927 DST or just 927 ST

Postby musicomm » 07 May 2012 16:36

Dear Stefano,
Thank you for your answer and forgive my poor English. It is a hard labor to express my thought in English #-o . Sometimes I feel embarrassed as much as my counterpart whom I talked to when I realized that my attitude made them confused and embarrassed. If I was rude, please undestand that it wasn't what I meant.

That is right,,there is no R82...I mistyped. It is R80.
And it was R35 not 37. I checked again and he told me turntable is R35 and tonearm is marked R36 and catridge R37.  (I hope I heard right this time ^^)

Now I have to explain again what I did to solve frequency problem. :lol:
I solved the problem using Hz converter.
Yes, I have solved the 50Hz frequency problem by using frequency converter which makes 60Hz electricity to 50Hz.

I wrote " The converter output is 100 V and 117 V only and I had to rewire to make the turntable for 100V".

That is also right. I had to rewire the green cable from 220 to 110 to make the turntable work with 110 voltage. Please see the picture attached. (yes,,,right, a picture tells more than my terrible English)

The center spindle which is shown in your web site is very different from what I have on mine (you wrote that "the original one is quite 'thin', 5 mm to allow for a precise centering of the vynil grooves: see a similar item fitted on a 927F at http://www.stefanopasini.it/EMT_index_927.htm and this can be fitted on any 927, as the glass platter"). But it doesn't mean the 5mm thin "record pin" of your 927F is "original" and mine is not original.

The center spindle what you have on 927F is not 927D spindle. The spindle of the D type 927 is not straight with 5mm diameter. It is conical shaped variable spindle which has diameter of 6.5mm (top of the spindle) and the bottom 7.5mm with 2.5°inclination so any LPs which is supposed(recommended) to have 7.24 to 7.33mm center hole but actually has 7.0 to 7.35mm , because of the tolerance of each LP manufacturer, can stop in the middle of the 927D's variable spindle. So the LP will be in the air little bit up on the platter and the spindle will be pushed lower with the help of the weight of the LP itself and another auxiliary weight to make LP contact the platter completely.
It is possible because the spindle has a spring which pushes up the spindle when there is no weight that presses down the spindle. You wrote that "My EMT 927F has a special 5mm record pin instead of the 7,5 mm standard to allow a perfect centering of the records, like the fabled 'laboratory' version 927D". But it is not right in two ways. First the D version doesn't have the 5mm thin 'Record pin". Second, If the standard spindle diameter is 7.5mm, there will not be many LPs which will fit to the "standard" spindle if not you expand the record hole by yourself.

And the "original" D version ("fabled 'laboratory' version 927D") used 'glassmat' instead of acrylic mat. This glass mat has the weight of 2.5kg and 4.9 mm thickness. As Jean said " The "D" means that it has a glass auxiliary platter (Glassmat ) , a special glass-rubber mat that replaced the standard acrylic mat . The "st" means that the power supply is made for the 139 stereo phono equalizer. The lighter acrylic mat ( 927 A ) has a felt brake to allow instant start/stop for broadcast use. With the glass auxiliary platter the clutch system can't be used but it is not a problem in domestic use." He is right when 'D' means that it is a special (fabled 'laboratory') version which has a glass mat. But may be wrong because glassmat was specially designed for professional use of checking original records.
(Anyway no 927 was designed for home use :wink: )

This glass mat has butyl rubber on the surface ( 1mm thickness under the glassmat and 2mm up of the mat) and it is extremely flat because the D version was specially made for checking for the first LPs by engineers - I don't know if I can call this as a LP - which is cut by cutting machine. The horizontality deflection of this super flat glass mat is far 'less than +- 0.05mm' which is decided? for a turntable for professional usage and 927 D version's horizontality deflection is almost not measurable. (for reference, horizontality deflection for consumer usage is less than 1mm)

The spindle , which you called " 5mm record pin" is also designed to make the LP location in the center of the platter (" for perfect centering of the records"), same idea as D version. This idea was originated with and used for old version (low serial No) of 927 and Lyrec AG40-2. Because the spindle ( 5mm record pin) is thinner than the record center hole it needs the Center weight which you have explained in your web site. The end of the Center weight will fill the space between 5mm spindle (record pin) and center hole of the LP . Without the help of the Center weight the LP on the paltter will not be correctly center located because the 5mm is too thin compare to the diameter of the hole of LP.

The motor is different too ( If I was informed right. But there were no way for me to check this) . I was told that the 927D motor has stronger torque that makes for the turntable to reach its proper speed in a second. With the felt brake, usual 927 is designed to reach proper speed in 0.5 second. As D version having no brake, EMT made its motor to have stronger torque. And this strong torque was needed for the original LP checking purpose.

And this D version has a different Optical locator. This Optical locator with scale indicates the lateral movement of the tonearm so it can check revolutionary eccentricity. The D version Optical locator moves two times faster than usual 927 locator.

I started this thead because I was confused with marks. My turntable is engraved as 927ST and name plate as 927D. It might not mean anything. But with the information I got from various sources and several 'EMT speciallist' I could believe that my 927 is a D version.
Nobody can sure what has happened when EMT had special orders from various customers. So it become fabled. :lol:

I might have wrong information. It will be good that somebody with correct information can correct me and I can grow my knowledge on this turntable.

Thank you again for your advice.

Kim
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