Internal damping of stock arm, experiences?

Due to space restrictions, my SL-1610Mk2 will be the front end in my livingrom for a while. There's simply no room for the big ones.

I already have the KAB silicone dampener (great mod, IMO) and the resonance cap, but since I need to replace the RCA's, I thought I might as well look into internal damping of the arm while I'm at it.

KAB has been internally damping arms with cotton, and is now also offering a rubber lining ( https://www.kabusa.com/ ), so I was wondering if any of you AOS'ers have experimented with this type of mods? External shrinktubing and such is out of the question, I want a clean look.

I updated my original SL1210 arm with very good results. I used industrial foam ear plugs. These roll thin in your fingers and slowly expand. This gives you time to insert into the tone arm tube. Also the rear weight stub can be removed and packed in the same way. I also rewired from the headshell right through to RCA plugs in one run with an Incognito kit. Whilst this was done I shrink wrapped the tone arm. All these tweets gave a massive improvement over the standard arm. I only changed the arm as I got a Jelco at a good price. Completing these mods I think you will hear a big difference in sound.

Good luck

I also want to find out if its really necessary to replace the techie arm
Im running with a Goldring cartridge with a 1042 stylus, Silicon damping similar to KAB, Heatshrink on the arm and an underslung counterweight and getting good results.
Before trying any further arm tweaks I have just upgraded my phono pre amp to ensure I have a very good signal path which will not mask any further detailed improvement in PU output.

I want to look at an existing arm filled with foam to dampen it. I intend to use a self expanding foam, similar to that used in the building industry to seal cavity gaps. This can be mixed oneself from two chemicals, the ratio of the mix determines the density of the foam.
My intention is to remove the techie arm and wiring. Remove the front plug and wires. Inset a bendy drinking straw into the arm tube to provide a path for the PU wires. Fill the arm with my mix of foam such that it expands to completely fill the volume between the arm tube inner and the bendy drinking straw. This will adhere to the arm tube inner and, in theory, improve rigidity of the tube and the damping of any " vibration" from the PU assembly or internal resonances.
Reasemble the arm and evaluate.
I also have some carbon fibre tube ready to try an alternative " straight arm " using a two tube coaxial arrangement with the same self expanding foam between inner and outer tube.
There are alternative fillings one could used based on silicon rubber but weight will be an issue

Early days, but Im sure some inexpensive tweaks must exist.
The latest technics decks still appear to use the same bendy arm.

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Originally Posted by Ianmac

The latest technics decks still appear to use the same bendy arm.

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and with excellent results judging by the new 1210 on demo at Bristol (sporting a 2M Black cart).

Ive had a look at filling my stock arm with cellfoam. Unfortunately after removing the 2 screws holding the head connector in place the socket refused to pull out of the arm. Attempts to really put some pull on this run the risk of damaging the arm. I found traces of araldite so looks like someone glued it in position at some time in an earlier life.
This was a blessing in disguise. !
I moved forward by building a Carbon fibre arm and a new aluminium head mount, machined from the solid.
For the arm I used a coaxial construction with 10mm outside tube and a 6mm inside tube with cellfoam in between the outer "inside" and inner "outside" diameters. The arm length and head mount were made to match the Technics Baerwald dimensions with the offset at precisely 23.6 degrees.
The prototype is running now on one of my decks with a Goldring 1012 and the results are very promising. Wide, balanced frequency range with none of the "muddiness" I experience with busy multi instrument music using the stock arm in various guises.
IMOP much better than the stock arm so will concentrate on finalising this design
I havent tried a silicon damper yet but will do so in the next week.
Cost so far £20 but dont mention the time Ive spent and self inflicted mistakes Ive made.
As soon as i get time i'll pull together some photos and hopefully test measurements from my test disc

Firefox is telling me not to log into the site due to security issues??

Perhaps a test run with the foam ear plugs might make sense? If you use the chemical foam, and then don't like it, it will be very difficult to remove. Too much damping can be too much of a good thing, and dull the sound a bit?


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I did try some cotton tubing back when I first re-wired my tonearm. It was pretty loose in there though, not tightly stuffed. I also tried some thick heatshrink. In both cases I remember the change being very small. Almost borderline psychological. I must say though that my sl1200 back then was pretty much stock, so I probably should do some more testing now that the TT is much improved.

I also briefly worked on a carbon tonearm, but had a problem building a cheap and accurate enough headshell for it. I now have easy access to a cnc laser cutter, so I will probably get back to it at some point. I also want to try the nice and simple linear and unipivot designs out there. But they are low in my long todo list.

Sure using chemical foam is final. Further change is a new Carbon tube and rebuild, not a problem, I have enough tube and want to experiment and measure using an aluminium inner tube to see if there is any difference in electrical /electromagnetic screening of the PU wires from the techie motor as the PU travels from outer to inner
Im certainly not dulling the sound.
I have two decks, one with the std arm + heatshrink + KAB type damper the other with my Carbon fibre arm so can do instant comparisons. At the moment the CF arm is by far the best but I will progress just a little more before drawing a conclusion

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Originally Posted by alphaGT

Perhaps a test run with the foam ear plugs might make sense? If you use the chemical foam, and then don't like it, it will be very difficult to remove. Too much damping can be too much of a good thing, and dull the sound a bit?


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Sounds like you've got everything under control. Just remember the scientific method, only one change at a time, so you'll know exactly what caused each change.


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With the variability in systems, results seem to vary. In my system, heatshrinking the SL1210Mk2 stock tonearm made a major improvement in sound. Plus that was when my turntable was still stock. It is fairly thick heatshrink that is shrunk on very snug. This turntable is the source component in my headphone based system so it's probably easier to hear differences in sound.

I've been giving some thought to rewiring the arm and adding damping with some cotton on the inside. So, will be following this thread closely to read the group's impressions of this mod. Although, I'm very skeptical of improvements attributed to the wiring.

I would say when I had the original arm on heatshrink worked very well. The major help with this mod was the tone arm rewire straight from cart to RCA plugs. Then the arm was then packed with compressed foam ear plugs. I felt the bass notes tightened up and highs were very clear. . The next noticeable difference was the foam earplugs in the tone arm end stub. Packed tight and screwed back on that also damped the arm very well.

Here is the tone arm rewire kit. Very worthwhile with the standard arm.
tps://www.ebay.co.uk/itm/171140634010

ISOKINETIK ISOTONE CARDAS REWIRE KIT FOR TECHNICS TURNTABLES SL1200 SL1210 ETC

Thanks for that link! It looks like a nice cable to add to the turntable. Did it come with decent instructions on carrying out the upgrade?
Also, I like your idea of packing the arm with foam ear plugs.

BTW, you mentioned when you had the original tonearm. Which one do you use now? Would you mind describing how much of an improvement it was to switch tonearms?

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Originally Posted by vs_jk

Thanks for that link! It looks like a nice cable to add to the turntable. Did it come with decent instructions on carrying out the upgrade?
Also, I like your idea of packing the arm with foam ear plugs.

BTW, you mentioned when you had the original tonearm. Which one do you use now? Would you mind describing how much of an improvement it was to switch tonearms?

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The kit comes with no instructions but there is loads of videos on you tube. It does come with silver solder and new pins. The only difficult part is resoldering the tags back to the tone arm plug(headshell end) Not hard just fiddly. If you need help just ask.

At a greater expense I moved up to a Jelco arm a SA-750. This made a very big improvement over the stock arm. It is more refined and is also oil damped. Saying that there is nothing wrong with the modified standard arm. I still have my modded arm here and even though I probably will never use it I have kept it as I like the look of it.

Progress to date.
Have finalised my Mk1 coaxial carbon fibre arm.
Its working extremely well, better channel separation, improved resolution on " busy" musical recordings, solid bass , clean treble & no adverse influence from the techie electronics and motordrive.
Im finding it difficult to explain how good 40 year old vinyl can sound on my tweaked 1200 ( PSU- 3 level, Bearing and arm)
The results are such that I will cease any attempts to try and improve the stock arm- (Im running with Silicon damper, Thick heatshrink sleeving and underslung counterweight)

I will move on to a Mk2 version where I can trim the weight of the headshell to match the precise measurements I now have for arm length and headshell size
The rigidy Im getting with the coaxial construction with cellfoam seem to be giving me the improved control of the headshell I was looking for.
From some of the posts I think it worthy of mention that cellfoam is quite different from earphone foam. Cellfoam adheres to contact surfaces "severely" and forms a structural bond, it also has the ability to attenuates low frequencies.
Ill finalise my Mk2 headshell dimensions and make another from the solid -- (someone hinted they had access to a CNC mill ?)
Will progress the Mk 2 with CF arriving this week and post photos in about two weeks time

Quote:

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Originally Posted by vs_jk

Thanks for that link! It looks like a nice cable to add to the turntable. Did it come with decent instructions on carrying out the upgrade?
Also, I like your idea of packing the arm with foam ear plugs.

BTW, you mentioned when you had the original tonearm. Which one do you use now? Would you mind describing how much of an improvement it was to switch tonearms?

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Quote:

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Originally Posted by Ianmac

Progress to date.
Have finalised my Mk1 coaxial carbon fibre arm.
Its working extremely well, better channel separation, improved resolution on " busy" musical recordings, solid bass , clean treble & no adverse influence from the techie electronics and motordrive.
Im finding it difficult to explain how good 40 year old vinyl can sound on my tweaked 1200 ( PSU- 3 level, Bearing and arm)
The results are such that I will cease any attempts to try and improve the stock arm- (Im running with Silicon damper, Thick heatshrink sleeving and underslung counterweight)

I will move on to a Mk2 version where I can trim the weight of the headshell to match the precise measurements I now have for arm length and headshell size
The rigidy Im getting with the coaxial construction with cellfoam seem to be giving me the improved control of the headshell I was looking for.
From some of the posts I think it worthy of mention that cellfoam is quite different from earphone foam. Cellfoam adheres to contact surfaces "severely" and forms a structural bond, it also has the ability to attenuates low frequencies.
Ill finalise my Mk2 headshell dimensions and make another from the solid -- (someone hinted they had access to a CNC mill ?)
Will progress the Mk 2 with CF arriving this week and post photos in about two weeks time

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Love your experimentation Ian and the advancement of the 1200. The best part is the mods are in reach cost wise of most people. Keep up the good work😃

Photo of my prototype arm and headshell.
Ill get the handle and silicon damper fitted and do an evaluation with /without damping.
I need to make a new paddle and arm mount as the new arm is 0.5 mm larger than the std techie, 10mm in lieu of 9.5mm[IMG]http://i824.photobucket.com/albums/z...m/DSCF7692.jpg[/IMG]

Quote:

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Originally Posted by Ianmac

Photo of my prototype arm and headshell.
Ill get the handle and silicon damper fitted and do an evaluation with /without damping.
I need to make a new paddle and arm mount as the new arm is 0.5 mm larger than the std techie, 10mm in lieu of 9.5mm[IMG]http://i824.photobucket.com/albums/z...m/DSCF7692.jpg[/IMG]

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That looks amazing Ian:D

Wow, agreed! Keep up the great work!

You should see his workshop 😉

Looks great Ian, I bet you could sell a few of those as it looks excellent!

I used the cotton when doing a re-wire of the stock arm, it worked beautifully, no complaints at all!

Damper fitted to-night.
Improved bass and mid range response, a little tighter.
Im now very happy with my arm I dont intend to do much more other than a rewire using silver stranded wire.
I need to move my deck through to my main system and run it on my ATC's to fully evaluate the bass and finalise the input settings on my phono pre

I will start to my other deck with a second CF coaxial arm and slightly modified headshell, I can take 2mm off the front which will reduce the weight and overhang. I will wire it with thinner silver wire (0.3mm) , fit an underslung counterweigh and improved stylus.
Away for the next week so get started on my return

First off, the stock tonearm tube on the Techie is very resonant. Having it well damped can only improve it. However, it can be taken to the next level :eyebrows:

Quote:

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Originally Posted by Ianmac

Photo of my prototype arm and headshell.
Ill get the handle and silicon damper fitted and do an evaluation with /without damping.
I need to make a new paddle and arm mount as the new arm is 0.5 mm larger than the std techie, 10mm in lieu of 9.5mm[IMG]http://i824.photobucket.com/albums/z...m/DSCF7692.jpg[/IMG]

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On the CF/aluminum tube arm I did, the aluminum tubing was a very snug fit into the CF tube. This was from an idea presented on this forum by Qwin (many, many thanks). I took the easy way out and bought a headshell from the 'bay but because the headshell end was so much lighter I had to add a headshell weight. I also installed upgraded tonearm wire at the same time. Not being able to do an A-B comparison, all I had to go on was "wow, this thing really sounds good now!". It really is a major step up over the stock tonearm tho'.

P.S. LOVE the new bearing :yay:

https://photos.smugmug.com/Component...04_1304-XL.jpg

Nice to know one can buy a headshell, It makes this mod do-able for many.
What was the headshell type you found ?

I did follow up Qwins suggestion of a Linn Headshell but could never find one so to move on I designed my own.
When I get back next week one of the things Ill do is give precise dimensions for the bits I make with photos and sketches as I mod my second deck.
I must agree it really is a major step up over the stock arm.

Quote:

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Originally Posted by Ianmac

Nice to know one can buy a headshell, It makes this mod do-able for many.
What was the headshell type you found ?

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I did a search on eBay for "straight tonearm headshell" and found some ones that look like this.
https://photos.smugmug.com/Component...104_1297-M.jpghttps://photos.smugmug.com/Component...104_1291-M.jpg

The stub of the headshell fits tightly into the CF tube (8mm I.D.) so no adhesive is needed. I used a leftover piece of tubing on the headshell finger lift to carefully adjust the azimuth.

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Originally Posted by RickeyM

I did a search on eBay for "straight tonearm headshell" and found some ones that look like this.
https://photos.smugmug.com/Component...104_1297-M.jpghttps://photos.smugmug.com/Component...104_1291-M.jpg

The stub of the headshell fits tightly into the CF tube (8mm I.D.) so no adhesive is needed. I used a leftover piece of tubing on the headshell finger lift to carefully adjust the azimuth.

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Perhaps a tiny screw to prevent it from twisting? To preserve your azimuth?


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Nice Ian :)

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Originally Posted by alphaGT

Perhaps a tiny screw to prevent it from twisting? To preserve your azimuth?


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Trust me, it's in there tight enough that it's not going to twist. The azimuth isn't going to change unless you forcibly change it. I didn't glue it in place in case I had to adjust it at a later date. About a year and a half later after the initial set-up, it's still in exactly the same place.

A snug fit. Looks great! Inspires me to try some of my own ideas.


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Quote:

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Originally Posted by Ianmac

Photo of my prototype arm and headshell.
Ill get the handle and silicon damper fitted and do an evaluation with /without damping.
I need to make a new paddle and arm mount as the new arm is 0.5 mm larger than the std techie, 10mm in lieu of 9.5mm[IMG]http://i824.photobucket.com/albums/z...m/DSCF7692.jpg[/IMG]

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Beautiful work !!!

Any chance you can make a headshell for a stock 1200 arm?

Here is my damper (inspired by well known design): steel base and 'towers', brass bath; grinder, drilling press and soldering. Silicone 60000 cct inside. Gives significant soud improvements in all registerts - sound is more tight and clear.

Attachment 19812

Can you post a few more pics so we can get a look at it from different angles. Very much interested.

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.

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.

Quote:

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Originally Posted by RickeyM

Can you post a few more pics so we can get a look at it from different angles. Very much interested.

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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.

Attachment 19872Attachment 19873

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.

Wow! I wish I had the skills for something like that.

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]http://i824.photobucket.com/albums/z...m/DSCF7803.jpg[/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]http://i824.photobucket.com/albums/z...SCF7670_cr.jpg[/IMG]
Some detail of the arm fixing into the techie
[IMG]http://i824.photobucket.com/albums/z...SCF7678_cr.jpg[/IMG]
Some detail of the head to arm fixing
[IMG]http://i824.photobucket.com/albums/z...m/DSCF7760.jpg[/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

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.

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!