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Alignment tools

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Drewan77 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Drewan77 Quote  Post ReplyReply Direct Link To This Post Posted: 06 Feb 2016 at 8:19pm
Sorry Ifor, I posted it but got an error so I'll try again:

I use the DEQX unit to check azimuth, probably not as accurate as the Fozgometer but it does help to see channel balance & adjust if necessary.  A screenshot with a mono album playing, taken during the setup of my new cartridge:

L1-R1=Subwoofers, L2-R2=Midrange, L3-R3=Tweeter dB readings

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Post Options Post Options   Thanks (0) Thanks(0)   Quote ICL1P Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2016 at 9:17am
Andrew, it clearly works, but it's even more expensive than the Fozgometer.
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Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 31 Aug 2017 at 8:45pm
Resurrecting my own thread about alignment tools I am still finding the Clearaudio tool useful. It uses the platter spindle as the corner of a right angle between the bar going to the pivot and the tangent line that the stylus lands on. It uses the 'crossing distance' as I call it, X = Sq root (N1 x N2) and the angle of about 91 degrees to the tangent line which some members will appreciate gives the maximum tracing error compared to the 90 degrees null.

Previously on hifi man shed... I have previously improved IMO on the Clearaudio tool's accuracy by sticking on self adhesive labels and carefully marking on the crossing lines and angles with thinner lines than the 1mm lines on the device as supplied. I have also been using a 6x magnifier (a textile magnifier from Maplin) as I shared a couple of years ago. I'm getting a 10x one to see if it adds clarity (image size vs depth of field).

So... I ordered some 3mm acrylic mirror tile (A4 was about £3.50 off the big river shop) then did some marking, drilling, and scribing to get the extra precision of lining up the surface mark with its reflection from underneath for zero parallax error. Strange at first but I then found I was looking at the reflected stylus moving back towards the reflected tangent line, cross checking with the usual direct image of the stylus and the surface line.

On the same mirrored protractor I also added a spindle hole at 26.67 (Lo - N1 for my SME arm and Phoenix cartridge, = 92.67 - 66.00) and a simpler right angle 66.0mm along from this. Pleased and slightly relieved to find the stylus was landing on the tangent line and the cantilever was along on the null line. If you have tried this you will know what is involved, I measured twice and cut my holes very carefully.

Yes it sounds really good. Slightly cleaner and more dynamic than before.

It struck me that moving the spindle hole along the 92.67mm (Lo for my arm and cart) long tangent line would allow slight changes to the first null distance like 64mm or 70mm with the Lo-N1 changing as it is equal to (N2-N1)/2 by definition. I have visualised an alignment tool with three parallel tracks, the 66mm (for Baerwald/Lofgren A IEC) null and two others, probably 64mm and 70mm. The spindle holes will be further out for the close inner nulls, and vice-versa. The SME's fixed length and offset angle fix the linear offset Lo so N1 and N2 are linked, unless you use thinner mounting bolts and wiggle the cartridge to change the offset angle slightly.



Edited by Fatmangolf - 31 Aug 2017 at 10:49pm
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2017 at 4:10pm
Well an (un)interesting development is that I used the newly verniered scale and read off the P2S/mounting distance and the baseline distance for the two protractors and calculated the effective length as 231.6 mm. After checking everything I concluded that the length of the cartridge was not 7.5 mm from stylus to screws but about 8mm. I checked this carefully with a ruler and it is 8.0 mm so not sure where I got 7.5 mm from. Doh!

For the Clearaudio protractor the effective length of my SME and Phoenix combo doesn't matter as the crossing distance is the geometric mean of the chosen nulls. For the second protractor I made there is a difference as spindle is slightly too close (0.2mm) to the baseline, as the linear offset of my setup is 92.87 mm not 92.67 mm. The net effect is that I had aligned for an inner null of 68mm and it sounds pretty good to me on a variety of records, which was the point really.

Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 19 Feb 2018 at 10:49pm
Ironically I ended up proving the technical approach above of Clearaudio plus calcs with an arc protractor. Conrad Hoffman's Arc Template Generator is a very handy utility and free. To be fair I did use the maths described in this thread to work out the nulls and some trial and error to get the ATG to print what I needed.

Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 2018 at 8:38pm
Having had some time stuck at home with a stomach bug I was exploring the Clearaudio Protractor's formulas. Starting with a few basics like X, the crossing distance, squared X2 = N1 x N2 = Leff2 - D2 (D = mounting distance, M in Dennes), I went back to Graeme Dennes' study of tonearm geometry.

I had forgotten that the linear offset Lo (Dennes' P) is only determined by the inner r1 and outer grooves r2 on the record and not by arm length or mounting distance! So the choice of offset length Leff and offset angle alpha (Beta in Dennes) determine the maximum error in the middle of the LP at crossing distance X (Ra in Dennes where equation 4 shows this is determined by the inner and outer groove radius, my r1 and r2). I'm not sure it makes the record sound better but it made me think.



Edited by Fatmangolf - 07 Oct 2018 at 6:47pm
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 2018 at 9:01pm
Out of curiosity I may go back to the Uni-DIN alignment again, starting from its 57.5mm inner groove from the DIN spec. I had started from Lo = 88mm before this and now wondered what the outer groove would be? About 136mm or 10mm in from DIN (and IEC) outer groove.

Rearranging equations 9 and 10 from Dennes to eliminate the inner and outer groove radius in turn, R1 and R2, gave me the equations for working these out from a known pair of null points. This works out where the equal peaks of Lofgren A/Baerwald would have been. Easier to explain with an example...

Fremer's UNIDIN nulls of 63.3mm and 112.5mm give 58.0mm and 134.1mm for example. Whereas his preferred Lofgren B with nulls 70.3mm and 117.2mm gives 64.9mm and 136.0mm as the equivalent inner and outer radius. Interesting that the outer radius is are similar for two dfifferent approaches but I suppose both of them sacrifice the outer groove tracing for the section of the tonearm arc that their designer had prioritised in their particular alignment.



Edited by Fatmangolf - 07 Oct 2018 at 6:49pm
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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