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Old 4th February 2002, 05:25 PM   #11
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Default TT forum

Thanks Bernard for posting this question. I emailled Jason(?) a few days before you posted asking for the same thing.

I can think of a few projects I would like to tackle, but most especially, can we have a DIY version of your linear tracker? It is a beautiful piece of engineering. Bowing deeply...

There are plenty of older TTs out there, like Garrards, Thorens etc that can be improved with some well thought out mods, and probably elevate them to a higher level of performance. Perfect for this site.

It's great to see a few responses here. Keep on rolling on.

PS: It's also good to see someone who likes PP tube amps, rather than the seemingly ubiquitous SETs, which I've yet to hear one I like. I am getting some transformers that should be suitable for Allen Wright's PP1C soon; 12W into 114dB horns might be enough I think.

Cheers
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Old 4th February 2002, 10:03 PM   #12
PassFan is offline PassFan  United States
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I just purchased a Thorens 166MKII off Ebay and I would love to find some mods also. You get my vote guys.
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Old 5th February 2002, 06:07 AM   #13
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Default Re: Hello all .... from a turntable nuts

Quote:
Originally posted by dice45
What I still am seeking here is a forum about DIY turntables. Does such exist here?
Bernhard,

TT disscussions yes... I have had many and have a good half dozen project tables down in "the lab".

I am hoping to put together something better than my Linn LP12/Ittok. I have a good idea where the arm will come from -- but i need something to put it on.

dave
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Old 5th February 2002, 07:20 AM   #14
dice45 is offline dice45  Germany
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Hello Tony


Quote:
Originally posted by Tonyb



Hi Bernhard,





{sigh} finally one not misspelling my 1st name







Quote:




Yes, you remember correctly. Now I am also considering a 50kg airborne flywheel with a light platter on a conventional bearing. Silk therad driven. This arrangement should have less energy storage and less smearing?


Honestly, Tony, i would not recommend that. Stick with your initial plan to have a super-heavy platter on a decent air bearing.

During the 70 the engineers from the Japanese company Melco proved by neasurements and listening comparisons that above 40kg of platter mass, the motor's, belt's, friction wheel's influence starts to disappear, but up to 40 kg mass, the influence can be heard and measured.

What my impedance matching theory always claimed and the experinental results from the Redpoint guys Thom and Peter seem to prove is that a vinyl record mounted on a vinyl platter leads to wonderful music and that high platter inertia counts.







BTW, i am hunting a decent air bearing of about 30kg weight, incredibly stiff in all directions, it does the platter keep form bouncing on the air film. Together with 25kg of vinyl am just at the platter weight/inertia i always wanted to have. The air bearing is shaped like a ring and so there is room for a nice cavity system. The cavities provide a vacuum reservoir for sucking the records against the platter.



As soon as i got a quote from the company, I let you know. How does that sound to you?







Quote:
I am still waiting for S/N 00002 of LT1. This way I would have some incentive to jump on my turntable. What do you say, Bernhard ? ;-)






I deeply regret to say that ser#1 to 3 is reserved, for Manfred, Hartmut and yours truly. As Manfred contributed so much to the LT-1's design, i do not even consider to ask himwhaether he's after ser#2. But about ser# 4 we can talk as far as you have a little patience











Hello Walker,



I must admit i prefer shellac to vinyl as far as sonics are concerned, and folks, i am not kidding here, i know what i am talking about. I made several listening comparisons concerning detail resolution, open-ness, musicality, body, correct soundstaging. Provided a proper stylus and an EQ curve close to being proper is used, it wins hands down (except against some extraordinary vinyl recordings). As i own some recording on shellac, vinyl- and CD-reissue, i see forward to a real A/B comparison as soon as my tonearm, TT and preamp is up and running.







On the down side: the ends of the audible frequency range. Oh yes, and finding the proper EQ curve







Hello Brett and Dave,







I have not yet seen my friend Jeremy Epstein here. I invited him to stop by, dunno what kept him from that so far. He built a Ladegaard tonearm for his Teres. Quite opposite to me, Jeremy is a cheapskate of ancient nobility , he seems to have the rare gift to make gold out of dirt. So his Ladegaard experiences would be an invaluable contribution for most DIYers here. What i could imagine: building a Ladegaard variant with the air fed to the slider, not to the rail and then to tailor an adjustment structure for slider and and rail which works similar to my LT-1 but waaayyy chaeper to realize. I have this structure ready in my head.



Consider, the Ladegaard can be DIYed for US $100 or so, and this already with exotic, expensive materials.







Hello Dave,



why don't you go out and buy a chunk of 2" marine grade birch plywood (or better take two layers of it), mount a platter/bearing unit from www.redpoint-audio-design.com on it? Could be you know the folks and ... they have vinyl platters







Hello Semperfi,



you are in good company with your balsa wood tonearm. You don't know know good. Linear tracker and VTA-pioneer David C.Shreve sent me a drawing of his latest tonearm wand version for his Rabco tonearm ;it was a combination of balsa and basswood, a fancy lightweight American hardwood. David reported that this combination was working best sonically.







If you got problems with the arm joint, i am sure we can work it out. May i suggest a unipivot design? One thing, a unipivot must have sufficient rotational inertia which can but not must affect the tonearm's effective mass; Stax e.g. has provided rotational inertia by adding two side bars carrying weights and mounted exactly at the pivot point position.







All for now, folks, i am glad about your positive response. Jason wrote me i shall tell him when i think there is enough interest. I think there is.
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Greets,
Bernhard
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Old 5th February 2002, 08:05 AM   #15
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Default D'oh

Apologies for the unintended disrespect Bernhard. I am usually more careful.
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Old 5th February 2002, 01:53 PM   #16
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Hi Bernhard,

Yes, please let me know when you locate a good air bearing. I just hope that the cost is not more than, for example, a complete Verdier turntable. Does Maplenoll have a good bearing? A used Maplenoll may not be that expensive.

There are different schools of turntable design, heavy vs. light platter. One gentleman (who used to set up turntables and audio systems for living) is cautioning me not to go for an air bearing due to all the problems he used to have with them. At the same time he recommends air bearing tonearms with a conventional platter bearing (he is a Melco fan). Some also claim that the platter air bearing changes with humidity, temperature, ... Other gentleman (a mechanical engineer) constructed a super heavy turntable in the past and now recommends a light platter and a heavy flywheel.

Some people suggest a very rigid loop between the platter - plinth - tonearm. Others, like Verdier, add dissimilar metals between the bearing and a platter just to create an impedance mismatch. So, take you pick...

And of course, S/N 00004 is more than fine. I had no idea that 00002 and 00003 were taken. There is no problem with patience.

Regards,

Tony
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Old 5th February 2002, 04:38 PM   #17
dice45 is offline dice45  Germany
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Hello Tony,







some remarks to issues you raised off-list and on-list; thought might be interesting to others, too:







Flywheel:


the Melco designer knew why he avoided it. So do i. In my book coupling of rotational inertia has to be either a very rigid one or has to be avoided at all, as rotating masses tend to chatter with each other via the coupling element. They exchange energy. I don't want that. The motor's inertia already is a spike in my eye. That's whay i am using an utterly stiff and slippery magnetic tape as belt.







I had an interesting discussion with a specialist for electric drives, he



designed hard disk drives e.g. . He stated that for a perfect speed control the ratio of stored rotational motor and disk energy should be within 0.5 and 2.0; this would make the speed regulator's work easy. But he restricted this statement to a very narrow speed range as the rotational energy is proportional to the square of angular speed. for a wide range of speeds as needed for a vinyl TT, he recommended to get the motor's inertia as far down as possible and the platter's inertia as high as possible. Then the resonant frequency of the system motor-belt-platter would be high enough to be inaudible and the resonace would get lost in the platter's high inertia.



Interesting, isn't it? Coming from a completely different approach, it states the same.







Silk string:


the string has a knot and the knot is a major PITA. You bet i



know how make the knot in a way the string is not twisted and obediently runs outside the pulley groove.Just, obedience ceases after a while. Magnetic tape OTOH is easy to splice exactly to desired length. And stiff. And slippery. Hence a resonance killer






Motor:



airborne platters have one drawback, the bearing has no friction contributing to the motor's base load. This constant base load dampens the motor's enthusiasm to produce rotaional oscillations. And if the total motor load consists of, say, 90% constant base load and 10% load variation caused by the changing stylus friction, the varying load component has less influnece on the platter speed i.e. dynamic speed constance is improved.



I think it is a brilliant idea to apply damping to the motor shaft directly; this can be done by a fan (i faintly remember the Melco does it that way) or by an eddy current brake which is adjustable by ear my favourite
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Bernhard
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Old 20th February 2002, 05:20 PM   #18
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what a drag! My message suddenly disappeared! I'll rewrite it.

Hi again Bernhard. I'm also interested in a DIY TT. Although I find 50+kilo platters to to be humourous and excessive, I enjoy reading about such projects.

I'd like to make a platter out of plaster (or cement, acrylic or wood) and coat it with (or better, dip it in) rubberized tool grip paint.

I'd don't have any technical expertise to offer, but I have a friend who's a skilled machinist (from near Munich, but now in my neighbourhood) and I hope someday we can make a couple great turntables. I don't have the $$,000s for an Oracle or whathaveyou, but I'm in awe of that level of precision technology and would like to learn more.

Now I'm using a Rega RB300 with Audio Technica 440 ML cartridge. For the price, this is a remarkable cartridge with 5-35,000 range. I plan to upgrade to the OC 9 MC cartridge, but as for a REAL upgrade, I can only dream for now.

Regards, Ron
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Old 23rd February 2002, 01:14 AM   #19
dice45 is offline dice45  Germany
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Hello Ron,



Quote:
Originally posted by eila

Hi again Bernhard. I'm also interested in a DIY TT. Although I find 50+kilo platters to to be humourous and excessive, I enjoy reading about such projects.


Great!

BTW, 50+ kilos is not that ridiculous, atleast not that much. During late 70ies and early 80ies there was a company named Melco. Their engineers investigated the platter intertia matter and fould out that just at about 40kg of platter weight, the sonic and measurable influence of motor and belt or rubwheel starts to vanish.




Quote:
I'd like to make a platter out of plaster (or cement, acrylic or wood) and coat it with (or better, dip it in) rubberized tool grip paint.
'fraid you have to decide , all platter materials you named behave quite different.

You have forgotten PVC, vinyl. Vinyl mechanically is a perfect impedance match to vinyl records. Hence fewer vibrations are relfected from the record's bottom surface. THe platter acts as a vibration sink, the surface noise decreases by about 6dB, the dark-grey background becomes black.



Hint: collect many records. Take those you do not like and stack-glue them to a 20cm high platter. Go to your mechanic and let him turn the outer diameter smooth. Or if you like it weird, let them look the way a stack of glued records look and go shock those guys with the slick looking acrylic platters, not only visually, also sonically



Not kidding, i plan to do this myself one day, just my stack of unloved records is not yet high enough.

Quote:
I'd don't have any technical expertise to offer, but I have a friend who's a skilled machinist (from near Munich, but now in my neighbourhood) and I hope someday we can make a couple great turntables. I don't have the $$,000s for an Oracle or whathaveyou, but I'm in awe of that level of precision technology and would like to learn more.
No Oracle, don't like them. I run a DIY TT equipped with a modified SME V and an Ortofon Rohmann. Magic combo. Just the TT has gotten awful wow recently, the motor is giving up. I built this TT 17 years ago. I plan to have the motor unit re-designed to maxon DC motor and stiff belt operation. My current task. Might be i sell my last remaining Oracle motor (Pabst GS 3809) on ebay in near future.



If you need some expertise, i am glad to help . If you have a goodwilled and skilled mechanic, you are jaded, you are lucky, my eyes are full of green envy (my mechanic is skilled but not good-willed at all, all the time claiming i rip him off, and at the moment i cannot afford to have a company produce my stuff).



Quote:
Now I'm using a Rega RB300 with Audio Technica 440 ML cartridge. For the price, this is a remarkable cartridge with 5-35,000 range. I plan to upgrade to the OC 9 MC cartridge, but as for a REAL upgrade, I can only dream for now.


From what i heared, i'd prefer the Audio Technica 440ML. I would buy one or two backup units and then choose one of them to glue the cantilver plug-in firmly into the cartridge body, using eopoxy resiin for that and filling it into any hole and cavity not affecting the cantilever's movements. But, before you start, please ask for details, got a lot of experience with that.



Claim: after i glued an AT440 ML and a Shure V15VMx, there will be very few sonic difference between them, they both will sound like coming from the same factory. They will sound right and very few MC cartridges will sound that right while adding detail resolution and tone colour saturation.



Point is: such a glued MM is a musical instrument, it simply sings. Like one of those rare top-notch MC cartridges from the Far East, Koetsu e.g.

Th OC9 is gorgeous for HiFi, but it does not sing, it is a cartridge for "objectivists", or, as i sometimes derogatorily call it, it is a cheap MC.
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Bernhard
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Old 23rd February 2002, 02:25 PM   #20
PassFan is offline PassFan  United States
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I'm with you guys from here on out. I aquired a Thorens turntable a month ago and recieved a cheapo preamp yesterday so I finally got to listen to it. I installed a brand new Grado blue and used my new cartridge alignment tool that came in yesterday also. WOW! It's all there again, and this with a 36.00 cheapo preamp that plugs into the wall! It's like sitting in the studio listening to a final mix. I never realized how sterile CDs sounded. I listened to vinyl as a kid but never paid any attention. I have some damping to do and recently purchased some solid silver tonearm wire off of ebay that I need to install. There is still more of this wire on ebay if anyone is interested. Its under Audio components/other.
Just wanted you guys to know another of us has seen the light, or lak of light versus the needle. Hey Jason, how about a turntable forumn. Please
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