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Thread: STOP the TECHIE 1200 Ringing !

  1. #1
    Join Date: Apr 2009

    Location: Ayrshire, Scotland

    Posts: 231
    I'm Ian.

    Default STOP the TECHIE 1200 Ringing !

    It has been some time since I did some real work on my techie 1200.I have some time now and have cleared 3 days from my Covid 19 lockdown schedule.

    4yrs ago when I was working with some forum members on Bearings and Power Supplies I had noted that I must look at the techie Platter.
    There were various posts on the forum re mods, expensive new replacments and a variety of aftermarket matts.
    One worked through replacing the rubber damping on the platter underside to reduce the platter "ringing". Ringing being a common issue used often by the aftermarket dealers to sell their goodies or snake oil.
    Never keen on modding anything unless for good reason I wanted to delve.
    To date I have contented myself with a variety of matts, mainly DIY slicone based but did make a 4mm copper top plate.

    My first look at my platters, one a MK2 deck the other a MK5, (I belive these are originals for the decks) got me thinking of how I could measure performance led me to thinking into how best to measure their performance.

    I wanted to measure the resonance of a stock platter.
    Resonance ( mechanical) is a vibration at a given frequency either unwanted ( Platter?) or wanted ( Tunning Fork)
    I often describe a turntable and its immediate electronics (phono pre) as a vibration amplifier, so why not try using its vibration detector (pick up) and electronics to do just that under a controlled situation.
    I had an old Shure pick up, a phono+pre amp and most importantly an oscilloscope so I could see whats going on. I am a great enthusiast of " seeing is believing" with all to do with audio--particularly turntables.

    My first go at measuring the resonance of my platter was designed to rest the pick up needle on the edge of a platter with the platter supported in a bearing, the bearing held in a bench mounted vice. The only contact point for the platter was the bearing shaft.
    The Shure M44 was connected to the phono pre input of a pre amp its output connected to an oscilloscope. A gentle tap on the platter outer are should show up any ringing or resonance on the scope display.
    System gain was set and left untouched throughout, the only variable being the intensity if my "gentle tap". What I was looking for was not a "precise tap" as this was an exploratory excercise looking for comparisons. Primarily the level of ringing before considering any mods and the level after any mods were done.

    The first photo show the basic meacuring set up. The Shure is fitted to an old techie arm and sitting over the TT spindle with height adjustment, clamped to the spindle when height was set. The platter was gently tapped and the resultant display on my Scope
    [IMG][/IMG]
    The second shows the scope display, a beautiful sine wave running at close to 250 HZ--- what a clean sinewave almost as good as a tuning fork.
    [IMG][/IMG]
    The issue associated with this resonance was to my mind the time it took to decay to zero from its start. On this platter it was close to 4 seconds - a long time
    There clearly was an issue here that required attention.
    My test set up also picked up any unwanted vibration from the workbench etc , and now that I had seen the level of this resonance I wanted to do many more tests with platters and their matts.
    Changing matts etc on this platter would be a hassle realining it, so I had to think of a better test set up.
    Back to the drawing board.

    This will be a long post so ill do it it chapters
    End of Chap1
    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

  2. #2
    Join Date: Apr 2009

    Location: Ayrshire, Scotland

    Posts: 231
    I'm Ian.

    Default

    Chapter 2
    A good nights sleep and bingo! Why the heck did I not think of this before.
    I had an almost ready made test jig where I could move the platter X and Y axis in increments of thousands of an inch and the Shure M44 up and down to the same increment on the Z axis.
    It was rock solid 15 cwt and not goining anywhere -- My workshop milling machine.
    A thorough machine clean down, then the platter base dust sealed and fitted to one of my bearing mod jigs, fixed the platter to the horizontal table, perfectly horizontal.
    Adapting a measuring clamp to hold the Shure, then, fitted to the mill vertical head gave me an accurate arm clamp.
    Phase two
    The photos shows the assembly, the electronics remained the same for the start of the measuring
    [IMG][/IMG]
    Detail of the platter to stylus arrangement.
    I can now easily move the platter away from the stylus to change whatever I need.
    [IMG][/IMG]
    The scope display, again a very clean sinewave. It is possible to just see the amplitude decrease from its starting level in the after display on the scope screen.
    [IMG][/IMG]
    I changed to a PC scope to display the following hoping it would be easier for some to understand
    The photo shows a few peaks along its length, the first two close to the LH start are from my "gentle tap" to get things moving.The second is derived fron the oscillations we saw on the analogue scope and show the frequency to be close to 250 Hz, The next peak is at 500 Hz and represents the 1st harmonic of the base 250hz. If i went into more detail you would see futher harmonics at 750hz,1000hz etc
    [IMG][/IMG]
    The next is the important one. You will recollect I mentioned that the time taken for the resonance to reduce to zero was a few seconds. This shows how the resonance signal reduces from its peak on the LH side to zero to on thr RHS and the accurate time taken.
    [IMG][/IMG]
    This one shows the same as the previous but the platter damping changed from the technics rubber undermat to a more upto date sound deadening and metal damping product readily available for about £10 per platter.
    There is a considerable reduction in the energy of the resonance signal, the overall area under the graph is much reduced, and the time it takes to reduce to zero, about 0.4 of a second opposed to 2-4 seconds on the original platter.
    [IMG][/IMG]
    I did a few more tests with the platter covered with various mats and started a basic test on my other platter. its response was similar with the resonant frequency at 280Hz

    The platter damping material I used so far is the well known dynamat extreme.
    The results on the techie playing a record are well worth the effort. Im not going into hi fi adjectives, as with all techie mods all machines must be modded in the same areas to truely compare like with like
    Getting the old techie rubber off the back of the platter as a sod of a job.
    This mod is worth doing.
    I would rate it in my top 4 , it could save you many pounds spent on expensive platter mats

    I must stop now but will continue with chapter 3 as soon as I get time.
    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

  3. #3
    Join Date: Mar 2014

    Location: KY - Scotland

    Posts: 5,465
    I'm Mike.

    Default

    How do you fancy trying my Mike New Platter for comparison, it's not being used right now and I can send it along to you test if you're interested.

  4. #4
    Join Date: Nov 2010

    Location: Yorkshire

    Posts: 9,302
    I'm Andrew.

    Default

    Excellent experiment.
    SS
    CD Teac VRDS25X(Audiotuned) DECK 1210 Mat Crystal Audio Mods MN Base/Bearing/Platter+Ebony armboard Feet Isonoe PSU Paul Hynes SR7EHD-27XL/DCSXL Ag DC lead/3 Stage Regs/Recap PCB+No Pitch/Strobe/Light ARM SME V(Kondo Ag Rewire&Tags) MC Cadenza Black FGS CABLES Arm Yannis SPD-4 IC Yannis 222 Litz+Ag bullets Power WAR PRE ATC SCA2 SPEAKERS ATC 50ASL STANDS Atacama PHONO Sugden Masterclass PA4 SUT Ortofon ST80SE POWER PSAudio P10

    VALVE
    PRE
    Croft Epoch(Modded) AMP Sondex S100 (Modded) SPEAKERS Tannoy 15"MG+RFC Warwick cabs+ Ref XO + Batpure supertweeters DECK Garrard 301 Mat Teunto Bearings 401(Bastin) Plinth Bamboo Arms 3009/3012 PSU Eagle+Tachometer MC Ag Meister II/FGS + Ortofon SPU MONO CABLES Arm Yannis 420.5 Litz+ SpeakerPC Tripple C+WBT-0681 Ag IC Oyaide FTVS-510 AgWBT 0110Ag Phonostages Paradise(4 Box Mega-Modded) / Croft Musicmaker



  5. #5
    Join Date: Sep 2014

    Location: brighton uk.

    Posts: 4,737
    I'm jamie.

    Default

    playing devils advocate here but who taps or knocks there platter when playing records? does the resonance produced by tapping exist in real world use?
    My System
    John Wood KT88 Amp.
    Paradise Phono Stage
    Sony TTS-8000 Turntable.
    PMAT-1010 MK6 Tonearm.
    Ortofon Cadenza Bronze
    Sony X555ES Cd Player
    Yamaha NS1000m Speakers

  6. #6
    Join Date: Nov 2010

    Location: Yorkshire

    Posts: 9,302
    I'm Andrew.

    Default

    Quote Originally Posted by karma67 View Post
    playing devils advocate here but who taps or knocks there platter when playing records? does the resonance produced by tapping exist in real world use?
    You'd also have to perfectly replicate the tap every time for consistent results.
    SS
    CD Teac VRDS25X(Audiotuned) DECK 1210 Mat Crystal Audio Mods MN Base/Bearing/Platter+Ebony armboard Feet Isonoe PSU Paul Hynes SR7EHD-27XL/DCSXL Ag DC lead/3 Stage Regs/Recap PCB+No Pitch/Strobe/Light ARM SME V(Kondo Ag Rewire&Tags) MC Cadenza Black FGS CABLES Arm Yannis SPD-4 IC Yannis 222 Litz+Ag bullets Power WAR PRE ATC SCA2 SPEAKERS ATC 50ASL STANDS Atacama PHONO Sugden Masterclass PA4 SUT Ortofon ST80SE POWER PSAudio P10

    VALVE
    PRE
    Croft Epoch(Modded) AMP Sondex S100 (Modded) SPEAKERS Tannoy 15"MG+RFC Warwick cabs+ Ref XO + Batpure supertweeters DECK Garrard 301 Mat Teunto Bearings 401(Bastin) Plinth Bamboo Arms 3009/3012 PSU Eagle+Tachometer MC Ag Meister II/FGS + Ortofon SPU MONO CABLES Arm Yannis 420.5 Litz+ SpeakerPC Tripple C+WBT-0681 Ag IC Oyaide FTVS-510 AgWBT 0110Ag Phonostages Paradise(4 Box Mega-Modded) / Croft Musicmaker



  7. #7
    Join Date: Mar 2017

    Location: Seaford UK

    Posts: 1,861
    I'm Dennis.

    Default

    Yes Andrew, but the point is to show a much better decay time, and only that parameter, and that has been done and is valid.

  8. #8
    Join Date: Sep 2017

    Location: Dublin

    Posts: 506
    I'm Pavel.

    Default

    In practice the stock Technics mat (especially the thick one) damps ringing very effectively, and hard mats (e.g. acrylic) make the mat+platter combo absolutely dead.

  9. #9
    Join Date: Nov 2010

    Location: Yorkshire

    Posts: 9,302
    I'm Andrew.

    Default

    Quote Originally Posted by Pharos View Post
    Yes Andrew, but the point is to show a much better decay time, and only that parameter, and that has been done and is valid.
    Yes Dennis, but not in a consistent way, no method of exact replication has been published, so until such evidence exists, the experiment is flawed and unreatable. All that's been proven is that by using Dynamat we can change measured decay time. Well, that's pretty much what the company relies on to sell it's product, so you could argue that this is an experiment proving something we already know. And if you want to be really pedantic we are not improving decay time, we are measuring changes and characteristics of measured resonance on a alloyed metallic structure with Dynamat application. But, hey, I'm not one for splitting hairs.
    SS
    CD Teac VRDS25X(Audiotuned) DECK 1210 Mat Crystal Audio Mods MN Base/Bearing/Platter+Ebony armboard Feet Isonoe PSU Paul Hynes SR7EHD-27XL/DCSXL Ag DC lead/3 Stage Regs/Recap PCB+No Pitch/Strobe/Light ARM SME V(Kondo Ag Rewire&Tags) MC Cadenza Black FGS CABLES Arm Yannis SPD-4 IC Yannis 222 Litz+Ag bullets Power WAR PRE ATC SCA2 SPEAKERS ATC 50ASL STANDS Atacama PHONO Sugden Masterclass PA4 SUT Ortofon ST80SE POWER PSAudio P10

    VALVE
    PRE
    Croft Epoch(Modded) AMP Sondex S100 (Modded) SPEAKERS Tannoy 15"MG+RFC Warwick cabs+ Ref XO + Batpure supertweeters DECK Garrard 301 Mat Teunto Bearings 401(Bastin) Plinth Bamboo Arms 3009/3012 PSU Eagle+Tachometer MC Ag Meister II/FGS + Ortofon SPU MONO CABLES Arm Yannis 420.5 Litz+ SpeakerPC Tripple C+WBT-0681 Ag IC Oyaide FTVS-510 AgWBT 0110Ag Phonostages Paradise(4 Box Mega-Modded) / Croft Musicmaker



  10. #10
    Join Date: Apr 2009

    Location: Ayrshire, Scotland

    Posts: 231
    I'm Ian.

    Default

    Some valid points, but bear in mind these measurements are relative, to prove to me that dampening the platter with a different material reduces the natural vibration of the platter and most importantly the decay time.

    I think it is worthwhile to look at this as an energy issue, the new material is much better at absobing the energy created by the platter oscillation, probably at the end of the day as heat. We are looking at forces at play which in our norm are miniscule. But they all add up to become significant at the low levels of signal we are dealing with.( 30 millivolts MC)

    Platter oscillation can be generated very easily at around 250 hz. No, we dont hit it when its playing records but other forces are at play. There will be noise from any bearing, where does that go, how is the energy dissipated ? The stylus running in a grove will generate forces at music frequencies. there will be a reaction to them by the record wanting to oppose them, where does that energy go, dissipated in a below record mat , passed on to the platter or just wear the record. Ignoring the effects of the tonearmat this point.
    Platter oscillation induced at say 250 hz in this case will cause an unwanted 250 hz signal to be induced into the stylus and add or subtract to the wanted signal. While we have shown resonance at 250 hz, there will be effects at higher and lower frequencies. One has to think a little out of the box.
    .

    I have gone a little further today. I recently purchased a Denon 103r from Mike. He gave me a cover for it that snuggly fits over the body, it was supposed to improve the performance.
    I took the cover off and installed some of our energy absober between the cover and my tone arm mounting . Wow the techie is really singing Ive never had it as good.
    My theory was to try and absorb the energy from the headshell.
    No different from fitting a silicone damper to the arm, they work well which proves there must be vibration travelling up the arm


    I did measurements with a variety of mats, steel and copper plates. Too many to list!
    Im currently running with the platter covered by a 0.5mm silicone plastic mesh ( IKEA for stopping carpets slipping) SDS matt cover with the same mesh with a hole cut in it to ensure the record label does not inhibit the record sitting on the mesh.
    Results are really good.
    Adding a thicker matt, rubber or silicone anywhere in the mix kills the dynamics

    When I measured my first modded bearing, accurate measurements showed a decrease in noise of 8db over that obtained from a standard set up. We may be looking at a rejection of unwanted signals of few more db here. It all adds up
    If I get time when this delving is finished, I will look at doing some more accurate noise figures. last time I used Arta software, I may have to look for a good soundcard for my PC
    Last edited by Ianmac; 24-05-2020 at 16:35. Reason: spelling
    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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