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Technics SL-1200 tonearm alignment for once and for all!There was a rather unpleasant discussion here about a week ago regarding the alignment of a cartridge on the tonearm of the Technics SL1200: unpleasant because of the potty mouthed contributions from one unregistered poster.
I’ve been busy lately; however, yesterday I found this link to the Panasonic website which gives the dimensions of the tonearm of the SL1200 mkII and the SL1200 mkV, the most common in this series of turntables (the mkI was a substantially different turntable, the mkIII was only available for a few years in the US, and the mkIV, which was unique in offering a 78RPM option, was only ever released in Japan).
http://www.panasonic.com/consumer_electronics/technics_dj/prod_specs_sl1200mk5.asp
As you can see, the tonearm dimensions are given in the above link as follows: effective length, 230 mm; overhang, 15 mm (corresponding to a mounting distance of 215 mm); offset angle, 22 degrees. The dimensions are the same for both the SL-1200 mkII and the SL-1200 mkV models, so it is reasonable to assume that the tonearms on the mkIII and mkIV models also had the same dimensions.
Several years ago, I prepared an excel file which allows the calculation of null radii from tonearm parameters, and vice versa. Steve of the analog dept kindly hosted this excel file, and you can find this on line here:
http://www.theanalogdept.com/images/spp6_pics/Alignment Spreadsheet/Arm Data Calculator.xls
By entering the tonearm parameters from Panasonic website in the cells highlighted in red in the top box of the first worksheet, the null radii of the Technics tonearm when a cartridge is aligned according to the manufacturer’s recommendations are produced. It can be seen that the Technics recommended null radii are 58.8 mm and 113.5 mm. These null radii are not unusual for a Japanese made tonearm.
If a user wishes to use an alignment protractor which is designed to give null radii at 66.0 mm and 120.9 mm (the so-called Baerwald alignment), then, since the mounting distance is fixed, the effective length and the offset angle of the cartridge have to be changed.
The same link above allows the calculation of the new tonearm parameters: just click on the worksheet tab marked “Null Radii+Mounting Distanceâ€, enter 66.0 mm and 120.9 mm for the null radii, and 215 mm for the mounting distance in the cells highlighted in red in the top box. The resulting effective length is produced in the second box down the page, the answer is 232.8 mm which means that the cartridge must be moved forward about 3mm in the headshell compared to the manufacturer’s alignment.
The offset angle is also produced in the second box down the page and it can be seen that this has increased to 23.7 degrees. These results are in line with the observations of most users (myself included) who have aligned a cartridge on the tonearm of a Technics SL-1200 using a standard protractor with grid centres at distances of 66.0 mm and 120.9 mm from the centre of the spindle hole, i.e. that the cartridge must be advanced to the front of the headshell, and skewed clockwise relative to the headshell when viewed for above.
The unpleasant discussion mentioned above can be found here:
http://www.audioasylum.com/audio/vinyl/messages/648979.html
IT is interesting because the picture posted by Ralph NLD verifies the results predicted above.
I hope this post clarifies the matter.
Best regards,
BK
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Topic - Technics SL-1200 tonearm alignment for once and for all! - B.K. 11:58:35 04/25/07 (30)
- perfect as usual Brian ! want an arc protractor for technics ? - Seb 05:31:48 04/27/07 (0)
- Re: Technics SL-1200 tonearm alignment for once and for all! - h.k 02:06:38 04/26/07 (0)
- Is it true that "royphil" was found strangled? - nightdoggy 15:18:25 04/25/07 (1)
- I've tried the Technics alignment jig and the TT Basics tool - olddude55 14:46:45 04/25/07 (0)
- My favorite protractor is... - Scottrt 14:44:00 04/25/07 (0)
- Great info, really cleared up the confusion but ... - texanater 13:31:10 04/25/07 (19)
- When you engineer a tonearm.... - tubesforever 14:57:13 04/25/07 (18)
- Thanks Tubes and BK ... Forgive me if this is a dumb quesiton - texanater 17:37:28 04/25/07 (7)
- Which speakers did you buy? - tubesforever 15:34:58 04/26/07 (4)
- I built a pair of GR Research AV/2 + sub - texanater 15:47:21 04/26/07 (3)
- Been building DIY now for 36 years.... - tubesforever 23:45:05 04/26/07 (2)
- What do you think about feet and stands? - texanater 06:01:05 04/27/07 (1)
- I got the cabinets from PartsExpress.....99 bucks a piece - tubesforever 11:09:28 04/27/07 (0)
- In principle a tonearm should be designed with aligned bearings; however ... - B.K. 02:35:03 04/26/07 (0)
- Your ears should be the final arbitor.... - tubesforever 00:14:55 04/26/07 (0)
- Re: When you engineer a tonearm.... - John Elison 17:14:51 04/25/07 (9)
- Sorry If I put words in your mouth you never muttered.... - tubesforever 23:39:36 04/25/07 (8)
- Re: Sorry If I put words in your mouth you never muttered.... - John Elison 05:13:09 04/26/07 (7)
- Exact number, John? - Muzikmike 10:05:49 04/26/07 (4)
- I've had 63.5 tables and 12.87 arms - nightdoggy 18:59:26 04/26/07 (0)
- I can't even tell you the exact number of tonearms I've owned in my life. ;-) (nt) - John Elison 10:59:08 04/26/07 (2)
- Im messing with you John..... - tubesforever 13:51:14 04/26/07 (1)
- I've decided I'm going to go with the Technics jig - nightdoggy 19:04:18 04/26/07 (0)
- Distortion at inner and outer grooves ....... - bornin50s 06:58:11 04/26/07 (1)
- Re: Distortion at inner and outer grooves ....... - John Elison 07:09:09 04/26/07 (0)
- Tracking Error Angle & (John's / Spreadsheet) - Ralph NLD 13:29:56 04/25/07 (1)
- Here are two graphs showing the difference between Technics' alignment and Baerwald's - John Elison 06:28:57 04/26/07 (0)
- Re: This is what I used on someone's SL-23 (the overhang thingy was long gone) - Damián 12:58:13 04/25/07 (0)
- Great! and - Ralph NLD 12:19:40 04/25/07 (0)
- Thanks!! Great information!!! /n - Ivan303 12:08:19 04/25/07 (0)