Angling for 90° - tangential pivot tonearms - Page 41 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 18th July 2012, 05:38 AM   #401
diyAudio Member
 
Esperado's Avatar
 
Join Date: Jul 2011
Location: France
Quote:
Originally Posted by berlinta View Post
Nope, same length. It's just a VERY small turntable ;-) Doesn't even have a full size platter(I'm not kidding).
Witch is a very bad practice, as the vinyl vibrations are not damped by the platter cover.
__________________
Ultimate Protection and more.The Only Source of Knowledge is experience, everything else is just information” ©A. Einstein
  Reply With Quote
Old 18th July 2012, 01:00 PM   #402
diyAudio Member
 
Join Date: May 2003
Location: Berlin Germany
Dear Christophe,
I must assume you have heard the turntable in question to be able to support your statement. Sorry to have missed you at the Munich show.

The first 6-8mm(depending upon the record mat used) of the modulated area are not in touch with the mat. I know many people who use mats like the ring mat or "dot"-mats(not my preference either, but still...), claiming that they prefer the results they are getting.

In reality, many records do not make full surface contact due to warps or being dished. I used a (moderately heavy)record weight and did not get any comments about the sound of the first few minutes being inferior to the rest of the record. Often the "lip" of post pancake era records prevents an intimate contact with "full size" or even larger record platters or mats.
I can also substitute the 276mm platter with a "full size" (300mm) platter(or a rigid mat like the Goldmund mat) and, guess what, the smaller platter yields superior results. Mmmhh..... so to take advantage of a full area record to mat interface(theoretically preferable off course), major design changes would have to be implemented(motor and drive system). That was never the goal. I just wanted to show that you can build a world class turntable based on a well tought out design from the early 60ies that is NOT the size of your average gravestone.
And I invite anyone to bring their full size platter deck and compare it to this inadequate little "toy":-)
It will be an eyeopener...

Lastly, here is a link to a deck(based on an Elac Miracord 50H) with magnetically suspended platter(~ 50gr. load on the trust area remaining) and a pivoted arm(just a modification of the original) with zero tracing error that I built for this years Frickelfest.

http://www.holgerbarske.com/wp-conte...12_fsps556.jpg

Easy to implement on many a deck that started life as a record changer... and it can be done in less than two days.

À bientôt,

Frank

Last edited by berlinta; 18th July 2012 at 01:03 PM.
  Reply With Quote
Old 18th July 2012, 07:35 PM   #403
diyAudio Member
 
directdriver's Avatar
 
Join Date: Nov 2005
Quote:
Originally Posted by berlinta View Post
a pivoted arm(just a modification of the original) with zero tracing error that I built for this year's Frickelfest. Easy to implement on many a deck that started life as a record changer... and it can be done in less than two days.
Thank you for showing the interesting arm. I think that's the most doable arm for DIYers. I have thought about such designs before but simply cannot think of a way to deal with the vertical movement that can affect the tangency. I guess when you have a warp record you will have mistracking regardless of design. Is there's any picture showing how the spindle is implemented? I have to assume the spindle is one of the fixed corners of the Thales circle. When the headshell goes up and down which creates a vertical arc and how can you deal with the spindle side when it's a vertical straight line as guidance? Do you just let it simply mistrack on those warping occasions? Instead of a single light mass straight tube as guiding rod, I thought using a fork-like two-rod guiding mechanism sliding pass the tall spindle. Downside is that it adds more mass...

I have a salvaged arm from a Kenwood KD-770D turntable that has a removable headshell and the armwand is straight which will be a great candidate for this experiment and it's reversible. The Graham Robin is also another good candidate.

Thanks again for your kind contribution to this thread. I really like keeping the spirit of playfulness in this thread, as some people are just so serious about everything. Keep the fun coming!


Click the image to open in full size.

Click the image to open in full size.

Last edited by directdriver; 18th July 2012 at 08:02 PM.
  Reply With Quote
Old 18th July 2012, 08:09 PM   #404
diyAudio Member
 
directdriver's Avatar
 
Join Date: Nov 2005
Okay, from the higher rez picture, I think I know how it's done. The spindle is an adaptor over the existing spindle space with top portion being a half diameter cylindrical piece and the skating force will keep the rod touching the spindle constantly. (How do you set anti-skating?) And the contact point is the dead center of the spindle. Clever!!

Frank, you're a genius!
  Reply With Quote
Old 18th July 2012, 08:40 PM   #405
diyAudio Member
 
directdriver's Avatar
 
Join Date: Nov 2005
I have to assume the plastic spindle is stationary and probably only works on a record changer as the spindle is hollow with a hole all the way to the bearing. I think a fork like rod will work for regular spindle in normal turntables.

Another angle:

Click the image to open in full size.

Last edited by directdriver; 18th July 2012 at 08:43 PM.
  Reply With Quote
Old 18th July 2012, 09:07 PM   #406
diyAudio Member
 
directdriver's Avatar
 
Join Date: Nov 2005
Picture of the other LT arm on the turntable with smaller platter.

Click the image to open in full size.
  Reply With Quote
Old 18th July 2012, 09:56 PM   #407
diyAudio Member
 
Join Date: May 2003
Location: Berlin Germany
Hi again,
The white center spindle is stationary and, since it's made out of Teflon(no stiction!) will only add (minimal)friction to the lateral movement. It can be seen as a damping device(working in both planes).
The headshell-plate can rotate, thanks to two ball bearings in the black, upper headshell section. The wiring can be bent to act as a spring so the headshell-plate and the carbon fibre tube(mass: 0,3gr!) that is attached to it at a 90° angle "leans" against the Teflon spindle. The slight pressure required can be generated by other means as well, but I wanted to keep it as simple as possible.
I actually should have left the Teflon piece at its 7,15mm diameter and should have mounted the thin CF tube a little forward of the stylus plane. Would work just fine and omits the need to turn the smallish Teflon piece excentrically(somewhat tricky to do, since Teflon "gives" quite a bit under pressure).

Since the bearing after the conversion is super quiet, no noise is transferred from the bearing to the headshell/cartridge via the CF tube.
One of the original ELAC spindles(for single play operation, used here) has a rotating section at record "height", so no additional noise from a stationary spindle "rubbing" against the inside of the spindle hole is generated.
Antiskating is set via the built in mechanism of the deck(its arm).

No mistracking occurs when playing warped records... I tested it with a tracking ability track with the test record slightly wedged to simulate a warp :-)

Downside: If one uses the somewhat stiff tonearm wiring to push the rod against the spindle you need to have room for the arm to be moved far to the right or you'll find it difficult to put on a record.The CF tube could be hinged off course.....

Try it, it works very well and it's worth the effort. Easy to compare(no tracing error vs. regular tracing error) the arm when the headshell plate is fixed in a conventional way(take out the washer between the black section and the headshell plate, fix it at the required offset angle, if need be, remove the CF tube...).

Have fun guys!

Frank

Last edited by berlinta; 18th July 2012 at 10:00 PM.
  Reply With Quote
Old 18th July 2012, 11:16 PM   #408
diyAudio Member
 
Esperado's Avatar
 
Join Date: Jul 2011
Location: France
Quote:
Originally Posted by berlinta View Post
The first 6-8mm(depending upon the record mat used) of the modulated area are not in touch with the mat.
Hi, Frank,
I just had a look on my turntable and can tell you that a cigarette paper is well stuck on the fist 5 millimeters from the edge between a record and the mat. My mat is flat (only a little hollow where is the paper label, and quite heavy. Silicon with carbon surface. And the record is pressed at the center.
I just can say it sound better than with the original mat not flat and light, But my plate is quite resonant too, so i presume the mat dump it as well. Difficult to make the part of both. (Dump of the record, dump of the plate).
We had designed a tripod plate for the company i was working for, long time ago,. SCIENTELEC TRIPOD TURNTABLE | Flickr - Photo Sharing!
It was not a so good idea, regarding sound, but ok for the look. ;-)
Reason of my remark.
__________________
Ultimate Protection and more.The Only Source of Knowledge is experience, everything else is just information” ©A. Einstein

Last edited by Esperado; 18th July 2012 at 11:19 PM.
  Reply With Quote
Old 19th July 2012, 09:08 AM   #409
diyAudio Member
 
Join Date: May 2003
Location: Berlin Germany
Hi Christophe,
Did you work for Rega too? I always thought this war Roy Gandhi's first turntable...

Google-Ergebnis für http://www.vinylengine.com/images/model/acos_rega_planet.jpg

Google-Ergebnis für http://members.shaw.ca/ken.j/_images/planet_tt/planet_tt_03.jpg

I know you didn't design this one :-) :

retro vintage modern hi-fi: Yamamura Turntable

The platter of the PE33 Studio, the basis for the small turntable I took to Munich, is made from two different materials - kind of nesting - and so inherently quite well damped. The mat you can see doesn't provide any additional damping(like a rubber mat would), but raises the record to where I needed it. It's physical properties are close to vinyl...

Cheers,

Frank
  Reply With Quote
Old 22nd October 2012, 09:18 PM   #410
diyAudio Member
 
directdriver's Avatar
 
Join Date: Nov 2005
Looks like Frank's LT arm is a commercial reality, as exhibited at this year's Rocky Mountain Audio Fest/RMAF. Here are some pictures I found on the internet. It looks more refined than previous versions. So far, no picture that shows the guiding mechanism underneath the rotating cantilevered plate... just like any trade secret.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

It's being imported to the USA and sold direct by Xact Audio and the introductry price is $8900.

Click the image to open in full size.

Last edited by directdriver; 22nd October 2012 at 09:24 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
GLIDING FOR 90° - mechanical linear tonearms: no airpump, no servo directdriver Analogue Source 29 3rd May 2014 06:24 AM
Angling of ports and/or drivers? Dave McReeferson Full Range 11 27th March 2012 08:45 PM
String suspension vs. uni pivot or gimball tonearms nghiep Analogue Source 26 13th August 2011 05:27 AM
Angling drivers left and right in a vertical line-array???? ozziozzi Multi-Way 12 16th January 2009 05:23 AM
Need Amp For 90-0-90 V DC Drafance007 Solid State 15 12th October 2003 09:03 PM


New To Site? Need Help?

All times are GMT. The time now is 06:48 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2