DIY Tonearm

[reubensm]

My experience with linear arm on a Technics SL5 (one in my collection) - when calibrated well, sounds quite good, when not calibrated well, sounds awful especially with poor tracking and can also be dangerous for the records.

But overall, the SL5 is a great piece of vinyl gear and one of the milestones in Technics' turntable history.

 

[jls001]

Finally got 500000 grade silicone oil, courtesy a friend, and applied it to all arm lifter moving parts. After multiple rounds of fine tuning the amount of silicone and tweaking the rate of the repelling spring, the arm is now able to slowly and gently drop on the record when the lift lever is released for downward drop

 

[Sumanta]

Congratulations!!!

 

[jls001]

Rewired the tonearm with a tinned copper multi stranded wire I bought from local market. I bought it because it was the thinnest I could find anywhere. I bought four different colours of red, green, white and blue and twisted red and green as a pair, and white and blue as second pair. I made it as a 1.5m single run from cartridge to phono preamp. The sound is surprisingly good. With burn in I'm hoping that the highs will become less recessed.

I've twisted the pairs fairly tightly. I'm using a moving iron cartridge right now, though I plan to swap out to a high output MC soon. Does the amount of twist change the capacitance of the wire? Any thoughts!

 

[omishra]

Does the amount of twist change the capacitance of the wire? Any thoughts!

Yes it changes capacitance. More tighter the twist, more the capacitance. I used that parallel wire twist for making small tuning caps in short wave radio. 1" wire pieces with 8-10 tunes can give ~5pF. For audio frequency i read somewhere 1Ft wire with 3-4 twist is okay.

 

[Hari Iyer]

Great Job and a well designed and planned execution :clapping:. Though i am not fully into Vinyls as of now, can see that a lot of passion has gone into making this tone-arm. Will try and drop-in one of the weekends for a listen if all tweaks / alignment are completed.

 

[keith_correa]

Yes it changes capacitance. More tighter the twist, more the capacitance. I used that parallel wire twist for making small tuning caps in short wave radio. 1" wire pieces with 8-10 tunes can give ~5pF. For audio frequency i read somewhere 1Ft wire with 3-4 twist is okay.

Isn't capacitance dependent on the space between conductors and the dielectric constant of the insulation?

 

[jls001]

I untwisted the tonearm wire and converted it into a proper 4-wire litz braid. Thanks, Keith for sending me step by step pictures of how to braid it. I also additionally saw the instructions over at Chimera Labs. Link below:

Chimera Labs Do it yourself - braiding Audio Cable

Compared to a simple twist, it does reduce the amount of noise picked up, but it isn't nearly enough, as I can still hear a raised noise floor even at regular listening volume. So I guess I'll have to revert to the earlier arrangement of using shielded coax from the base of the arm to phono pre.

FWIW, the wire that I'm using now is dirt cheap but sounding quite good. I expect it to sound even better with burn in. If nothing else, at least I learned how to weave litz braid

 

[Sumanta]

If nothing else, at least I learned how to weave litz braid

That's my basic boost too for any DIY. For all I think.

My tone arms are waiting for wires. It will take some more time.

 

[jls001]

The litz braided tonearm wire is now discarded as another idea that almost worked

I have reverted to using two sections of wires - one from the headshell to the base of the arm, and another section from arm base to phono pre.

The first section is now replaced with Teflon insulated wires cannibalised from another old headphone. Section two remains the Belden 1855A video wire. I've also inserted a braided shield taken from a thin RG 174 coaxial wire within the arm tube, and inserted the wires within this braid. The braid is electrically connected to the phono pre earth terminal by a dedicated ground wire. I think this helps reduce noise pickup by some amount. At regular listening level, there is complete silence. At much higher volume there is noise, most probably the self noise of the electronics chain. Luckily there's no 50 hertz hum

This is the second time I'm using headphone wire for tonearm wiring, and I must say I'm very impressed with the quality of sound they're capable of producing, despite being just cheap headphones that came bundled with mobile phones. It is certainly better than the cheap wires used in the litz braid (though to be fair I didn't wait to burn it in properly, and the sound ought to improve with more hours).

 

[jls001]

And here's a useful cartridge mod - the Longhorn mod.

More details here:avahifi - Audio Basics Newsletter (1982 issue)

 

[jls001]

Impressed with what it did to the Denon DL 103, I made one for my other TT too:

That's a Denon DL 160 on my DIY arm. It makes good music.

 

[Hari Iyer]

How are you planning. to execute antiskating?

 

[Sumanta]

Reading now.

 

[jls001]

How are you planning. to execute antiskating?

Temporarily rigged up this:

I've been using no anti skate and it works. But recently I was watching this video newsletter from Origin Live. It spelled out the advantages of antiskate, so I thought I'll try it for myself:

https://www.youtube.com/watch?v=2Aa8em5LXDM

Skating is a complex and ever changing force. We can only hope to exert an anti skate which is at best the average value. Interesting discussions here:

Anti-Skate Question - Vinyl Engine

 

[jls001]

Improved, "semi final" version of the antiskate mechanism:

Don't ask me how I determined the separation of the grooves where the string hangs. I just cut them at 5 mm interval because any closer and they'd look cluttered

To determine which slot is best suited, I simply tried hanging the string in different grooves and check whether it exerts a slight outward force when the arm is balanced and suspended in free air with the anti skate on. Not the best of test, but in the absence of a sensitive device to measure the force exerted by the suspended weight, this was what I could think of.

 

[shafic]

Josh, can I call you a 'vinyl jamesbond'?
Great ideas!! Where do you get them from?:cheers:

 

[Sumanta]

Joshua, do you really need anti skating for a 12" arm?

I haven't considered it yet although it can be done for both my WIP unipivot and magnetic (Schroeder concept) arms of 12" arms. But reading in forums didn't push that requirement in design yet.
Why you went for anti-skating?

 

[omishra]

Joshua, does that cartridge mode only required for unipivot arm? I expect it to provide horizontal stability, may not be for 2 bearing tonearms.

 

[mbhangui]

Josh, can I call you a 'vinyl jamesbond'?
Great ideas!! Where do you get them from?:cheers:

Time to change the HFV handle to jls007. Put a condenser mic inside, gift it to Putin, it will become a super hi-tech spying device