Has anybody actually replaced the suspension "wire" on a MA-505 tonearm? Someone gave me one (I believe it is the
mkI due to the on the fly VTA adjustment) and the suspension wire for tracking force is broken. After researching
on the web, there were posts that it is tungsten and people have used corona wire out of a laser printer.
Well, I really don't think its tungsten or metal for that matter. I measured the thickness of the still attached
broken piece and it was like 0.18 mm thick. I ordered some 99.99% tungsten wire and it came today. It is way to
stiff. So I started slimming it down by running a length through sandpaper pinched between my fingers. I got it
down to 0.12 after remeasuring the existing wire multiple time.
So then I went to install it and went to attach the new wire to the spring. Well, it does not solder so I looked
close at the old one and there was a tiny crimped ferule. But I also looked close at the broken end and scraped it
with an exacto. The end kind of frayed like a piece of thread and I could see the many individual strands!
Anyway I attached the spring and routed it to the tension pulley. Even though I have thinned it down by a
third, it still seems way too stiff to work properly. The wire actually deforms semi-permanently as it is pulled
over the anti skate rods by the pulley. Lowering the tension does let the spring pull the wire back in but you
can see the residual bends in the wire. This to me does not seem correct if this mechanism is to control tension
real time. The spring actually does that I know, but if this wire doesn't actually conform easily to its path
through the tensioner, I would also think I has to much stiffness and therefore drag where it emerges from the
barrel holding the spring.
Can anybody really confirm this is tungsten wire ( as nylon thread would seem more appropriate)? If so, what is
its true thickness. To be flexible enough it would have to be an order of magnitude thinner than what I have
measured. I am pretty sure what was in the TT when I got it is the original as the tensioner related set screws
still had the bluish glue/threadlock in their holes so it appears to never having been replace. The "wire" looks
more like thread or silk as it frays and it is not shiny like the tungsten (after thinning)
Thanks much!
mkI due to the on the fly VTA adjustment) and the suspension wire for tracking force is broken. After researching
on the web, there were posts that it is tungsten and people have used corona wire out of a laser printer.
Well, I really don't think its tungsten or metal for that matter. I measured the thickness of the still attached
broken piece and it was like 0.18 mm thick. I ordered some 99.99% tungsten wire and it came today. It is way to
stiff. So I started slimming it down by running a length through sandpaper pinched between my fingers. I got it
down to 0.12 after remeasuring the existing wire multiple time.
So then I went to install it and went to attach the new wire to the spring. Well, it does not solder so I looked
close at the old one and there was a tiny crimped ferule. But I also looked close at the broken end and scraped it
with an exacto. The end kind of frayed like a piece of thread and I could see the many individual strands!
Anyway I attached the spring and routed it to the tension pulley. Even though I have thinned it down by a
third, it still seems way too stiff to work properly. The wire actually deforms semi-permanently as it is pulled
over the anti skate rods by the pulley. Lowering the tension does let the spring pull the wire back in but you
can see the residual bends in the wire. This to me does not seem correct if this mechanism is to control tension
real time. The spring actually does that I know, but if this wire doesn't actually conform easily to its path
through the tensioner, I would also think I has to much stiffness and therefore drag where it emerges from the
barrel holding the spring.
Can anybody really confirm this is tungsten wire ( as nylon thread would seem more appropriate)? If so, what is
its true thickness. To be flexible enough it would have to be an order of magnitude thinner than what I have
measured. I am pretty sure what was in the TT when I got it is the original as the tensioner related set screws
still had the bluish glue/threadlock in their holes so it appears to never having been replace. The "wire" looks
more like thread or silk as it frays and it is not shiny like the tungsten (after thinning)
Thanks much!
Amazon sells very thin (~.3mm) steel fishing line. It consists of 7 individual strands with a nylon sheath. Like this. Not real expensive, either.
If you have a well-equipped fishing supply store nearby they might stock something similar. It's larger in diameter than the original but might work OK. Being sold as fishing line means it probably is pretty flexible.
The same fishing supply store probably has crimpable ferrules for the ends. The individual wires on a frayed end probably would easily penetrate skin, so be careful when you're working with it. The steel might be difficult to cut with ordinary cutters. Hardened-steel cutters used for cutting bicycle brake and derailleur cables would do the job. A rotary cutter with an abrasive wheel might work too, but it could be difficult to hold the cable securely enough while attempting the cut. An oxyacetylene torch would do it in a flash (literally).
Good Luck!
Mark
If you have a well-equipped fishing supply store nearby they might stock something similar. It's larger in diameter than the original but might work OK. Being sold as fishing line means it probably is pretty flexible.
The same fishing supply store probably has crimpable ferrules for the ends. The individual wires on a frayed end probably would easily penetrate skin, so be careful when you're working with it. The steel might be difficult to cut with ordinary cutters. Hardened-steel cutters used for cutting bicycle brake and derailleur cables would do the job. A rotary cutter with an abrasive wheel might work too, but it could be difficult to hold the cable securely enough while attempting the cut. An oxyacetylene torch would do it in a flash (literally).
Good Luck!
Mark
Thanks- I'll check it out. Amazon sell tungsten(if that is really what the original is) down to 0.01 mm. I looked up the tensile strength of tungsten and found it is like the strongest metal. Based on the tensile strength, I can calculate the strength of the wire - the 0.18mm I bought should hold like 1.2 kilograms which I will try and measure today. Since the tension in the tone arm is in the order of grams (need to take some measurements to confirm lever arm factors), I may try calculating what the thinnest tungsten which support the needed tension and get some of that. The fishing multi stranded stuff sounds promising though so I'll head down to the local sporting goods store today or tomorrow.
Just wanted to post my findings in case someone is searching. I ordered some 0.05 99.99% tungsten wire and that is much more appropriate. It still strong (on the order of 200 grams tensile strength) and is flexible enough to bend/flex fully around the pulleys. Being so fine it is a bit hard to work with as it's hard to see but also tends to curl on itself. When you have to uncurl it you have unwind the curl rather than just pulling to straighten it. I did it that way the first but that results in links that are in visible but can be felt if pulled through two pinched fingernails.
Also, it would be impossible to thread into the spring canister by itself- I tied it to the 0.18mm wire from the first attempt and pulled it through.
There is a pulley deep within the canister that you have to visually confirm it goes under neath of.
2 meters was like $7.
It is all installed but I am awaiting a cartridge before calibrating the tension.
Also, it would be impossible to thread into the spring canister by itself- I tied it to the 0.18mm wire from the first attempt and pulled it through.
There is a pulley deep within the canister that you have to visually confirm it goes under neath of.
2 meters was like $7.
It is all installed but I am awaiting a cartridge before calibrating the tension.
I'm skeptical that it is tungsten. There's no indication that the info came directly from Micro-Seiki. I have seen lots of "information" on the internet that simply isn't correct.
Post #1 mentions that the end of the original piece of wire had a lot of individual filaments, like fabric thread. That sounds like cable to me. But if tungsten works....
Post #1 mentions that the end of the original piece of wire had a lot of individual filaments, like fabric thread. That sounds like cable to me. But if tungsten works....
The MA-505 operating manual is clear - its tungsten wire. It mentions it is tested to 4.5kgf, suggesting its about 0.045 mm^2, or 0.25mm diameter, given tungsten's yield stress of about 1GPa.