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Thread: Internal damping of stock arm, experiences?

  1. #31
    Join Date: Oct 2014

    Location: East Coast USA

    Posts: 96
    I'm Nathan.

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    Can you post a few more pics so we can get a look at it from different angles. Very much interested.
    We the willing, working for the unknowing, are doing the impossible for the ungrateful.
    We have done so much for so long with so little, we are now qualified to do anything with nothing.

  2. #32
    Join Date: May 2014

    Location: Sunny Lancashire

    Posts: 80
    I'm Chris.

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    Ianmac - how did you work out how long to make the CF tube and what is the offset angle of your headshell? I've managed to get hold of some (and alu inner pipe) to do the job, just need to figure out how to calculate the arm length...

    The headshell i bought of the bay has an offset of 21.3degrees but i think the technics offset needs to be 22degrees if i'm not mistaken (Qwin states that on his arc template)- might be able to take that up in adjusting the cart in the headshell but not sure yet...

    Chris.

  3. #33
    Join Date: Apr 2009

    Location: Ayrshire, Scotland

    Posts: 231
    I'm Ian.

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    Chris
    Ive just made my 2nd arm to night, waiting on the foam hardening.

    Go to Vinylengine.com
    Download their Technics Baerwald Arc Protractor. This for the 215mm mounting distance of the 1200.
    Print this on a 1:1 scale on your printer, you will need it to align your head. Check the 140mm reference scale at the top of the chart is 140mm on your printout. I had some hassle with my printer persuading it to print 1:1 exactly.

    You will see the angle of offset is 23.66 degrees.
    The effective length is 232.82 This is the length from the centre of the arm horizontal pivot to the stylus.

    From the effective length you have to subtract the distance from your stylus to the headshell entry for the arm,on the arm centre line axis (A) and the distance from the arm exit point on the technics pivot to the centre of the arm horizontal pivot (B)
    On mine A is approx 46mm B is approx 31mm so the actual part of the arm you can see between the techie pivot exit and headshell inlet is 232.86 - (A +B).= 154.86.
    On my deck it measures 156mm (L seen)

    (Given I made my own headshell I set my stylus cartridge with the mounting screws roughly in the middle of the headshell slots so the stylus is approximately on the crossover point between the arm axis and the offset axis.)

    Add to (Lseen) the distance your arm will project into the headshell (LH), on mine 15mm, and the distance the arm will project into the Techie pivot( LP), on mine 22mm ADD an adjustment tolerance of 2mm (Ladj)to allow a fine tune the headshell position
    Add Lseen + LH + LP + Ladj to get the length you cut the arm to. On mine 156 +15+22+2 =195 mm

    As ever measure thrice cut once
    If in any doubt cut the arm longer, you can always shorten it

    Re your offset I think you should be able to adjust the angle within the tolerance of the headshell slot widths.

    Using this protractor and measurements my stylus falls exactly on the Baerwald arc, all I had to tweak was the precise effective length by adjusting the headshell position

    Hope this all makes sense.
    Technics 1200 tweaked,Ianmac Bearing,DACT DIY Phono Pre, Belcanto CD-2, Engineered Switzerland DIY Renderer, Benchmark DAC2, Hypex NCore, ATC SCM40
    2nd system --Engineered Switzerland DIY streamer, Sony CDP11,Topping D50 DAC, Hypex NCore. Kef 1point2 speakers. Ianmac Filters

  4. #34
    Join Date: Sep 2015

    Location: Minsk, Belarus

    Posts: 30
    I'm Valera.

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    Quote Originally Posted by RickeyM View Post
    Can you post a few more pics so we can get a look at it from different angles. Very much interested.
    Of course, see attached photos. It's a rather 'weekend project' and I made this damper for sound test... but now I won't to dismount device.

    IMG_2351.jpgIMG_2356.jpg

    Regarding tonearm damping in general I think external silicone damper has the most effect, then heatshrink tube over the tonearm tube (it works well on any metal tonearm). Internal damping by wool can exclude 'organ resonance' inside tube - no more, I just put cartridge wires to separate cotton tubes and got the same effect. I think the best choise is to change tube material from metal (steel, aluminum etc.) to some composite one.
    Analog: Technics SL-1200MkII (RB300 tonearm, external PSU, separated power supply for all stages, improved bearing), MC Goldring Eroica LX, custom SUT 1:10, Balanced input J-FET DIY phonostage
    Digital: Cubietruck (headless Debian server, i2s output, external masterclock from DAC), content on HDD. DAC: Lynx D29v4 (Altera FPGA digital stream separator, 2*AD1853, 2*3 OP42 LPF)
    PA: DIY composite amplifier YES-3, schematic by Gennady Bragin
    Acoustic: DIY floorstanding 3-way SB Acoustics

  5. #35
    Join Date: Oct 2014

    Location: East Coast USA

    Posts: 96
    I'm Nathan.

    Default

    Wow! I wish I had the skills for something like that.
    We the willing, working for the unknowing, are doing the impossible for the ungrateful.
    We have done so much for so long with so little, we are now qualified to do anything with nothing.

  6. #36
    Join Date: Apr 2009

    Location: Ayrshire, Scotland

    Posts: 231
    I'm Ian.

    Default Final CF arm

    I have finalised my arm, no changes in construction, minor tweaks to the headshell size to reduce weight
    The Photo shows my Mk 5 deck with Goldring cartridge
    [IMG][/IMG]

    It also shows a copper plate I made for the platter to compare against a SDS plate I had purchased. I initially could not get the SDS plate to sound right and it took me some time to sort it out.
    There is a long story but some STOPP from IKEA helped enormously. Circa £3.
    Copper plate to my ears sounds better - and a lot cheaper-
    I wont deviate from the theme of this thread which is to do with arm but post another thread as soon as get time.
    The next shows the Arm components[IMG][/IMG]
    Some detail of the arm fixing into the techie
    [IMG][/IMG]
    Some detail of the head to arm fixing
    [IMG][/IMG]
    Ill start another thread on the finalisation of all my tweaks.
    Interesting journey making the copper plate and getting it Flat
    Anyone used an adhesive to marry their SDS plate to the techie platter?
    Ian
    Technics 1200 tweaked,Ianmac Bearing,DACT DIY Phono Pre, Belcanto CD-2, Engineered Switzerland DIY Renderer, Benchmark DAC2, Hypex NCore, ATC SCM40
    2nd system --Engineered Switzerland DIY streamer, Sony CDP11,Topping D50 DAC, Hypex NCore. Kef 1point2 speakers. Ianmac Filters

  7. #37
    Join Date: Oct 2014

    Location: East Coast USA

    Posts: 96
    I'm Nathan.

    Default

    Great looking work, how's the sound? When I did mine it was impossible to do an A-B comparison but I did have a sense of hearing the music "better", if that makes any sense.
    We the willing, working for the unknowing, are doing the impossible for the ungrateful.
    We have done so much for so long with so little, we are now qualified to do anything with nothing.

  8. #38
    Join Date: Apr 2009

    Location: Ayrshire, Scotland

    Posts: 231
    I'm Ian.

    Default

    Sound is superb.
    Both decks are identical with the same cartridge fitted to each. the only variant that follows each cartridge is the mat used between the platter plate and vinyl
    There are differences between the two carts i'm using . The Goldring is warmest with a more relaxed sound but I would like a better HF response. The Grado red has a good HF, transient response and channel separation, much better than the goldring but more tiring to listen to. I am tweaking the input impedance of my phono amp to better match the Grado.
    I dont think there is much more I can do to my techies to improve their performance and am about to cease tweaking.
    I had intended to do a final post listing all the DIY tweaks I have done but there is so little response to any threads relating to the now old 1200 I dont think its worth the effort. Perhaps the world has moved onto the 1200GR?
    I intend to fit a MM Phono pre and its PSU into the phono cable outlet compartment of my Mk11. I have the boards ready to do this, just to build a dual PSU, one for the deck one for the Phono, into one nice box.
    My Mk 5 will be fitted with an MC cartridge when I establish the suitable types and pick one up at a reasonable price.
    Maybe that will be me finished!
    Technics 1200 tweaked,Ianmac Bearing,DACT DIY Phono Pre, Belcanto CD-2, Engineered Switzerland DIY Renderer, Benchmark DAC2, Hypex NCore, ATC SCM40
    2nd system --Engineered Switzerland DIY streamer, Sony CDP11,Topping D50 DAC, Hypex NCore. Kef 1point2 speakers. Ianmac Filters

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