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I finally got around to rewiring my tonearm last night. Took a bit of fiddling around to pull the wires through, but it all worked out. I haven't had time to listen yet - it was 11p by the time I was done and everyone was in bed. The overall capacitance measure of the new tonearm + cable is significantly lower than the original:
Original measures were 350+pF per channel and now both measure about 57pF (no cartridge installed).
I used the KAB SuperFlex Litz wire and a 1m set of BlueJeans cables for the external run. The BlueJeans wires are SO MUCH thicker than the originals, that the metal plate that goes on the bottom of the tone arm assembly no longer fits back into place. I thought about cutting it to make it fit, but there won't be much of the plate left after doing so. Its thickness and composition make me think it adds both structural support to the tonearm mechanism as well as providing some shielding, though...
I was able to stuff three of the cotton pads into the cartridge end of the tonearm. I didn't bother removing the other end of the arm wand. Is there any additional benefit to gain by adding some shrink wrap to the outside of the arm or will this change the mass/compliance matching too much?
I'll give it a spin tonight to see what the results are.
Original measures were 350+pF per channel and now both measure about 57pF (no cartridge installed).
I used the KAB SuperFlex Litz wire and a 1m set of BlueJeans cables for the external run. The BlueJeans wires are SO MUCH thicker than the originals, that the metal plate that goes on the bottom of the tone arm assembly no longer fits back into place. I thought about cutting it to make it fit, but there won't be much of the plate left after doing so. Its thickness and composition make me think it adds both structural support to the tonearm mechanism as well as providing some shielding, though...
I was able to stuff three of the cotton pads into the cartridge end of the tonearm. I didn't bother removing the other end of the arm wand. Is there any additional benefit to gain by adding some shrink wrap to the outside of the arm or will this change the mass/compliance matching too much?
I'll give it a spin tonight to see what the results are.
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If you can present less than 150pF (including the phonostage) to the AT150MLX, it is, by all accounts, one of the best cartridges available at any price. The trick is having less than 150pF,(as the response rises pretty severely with in increase in capacitance) and almost every tonearm/cable on the market has (significantly) more than that.
That cartridge, along with a phonostage almost specifically made for it, are on my list of things to build.
The shrink wrap on the armtube is likely popular because it is easy to do and appears to do something. I can't imagine it doing anything other than adding mass to an area you really don't want it.
That cartridge, along with a phonostage almost specifically made for it, are on my list of things to build.
The shrink wrap on the armtube is likely popular because it is easy to do and appears to do something. I can't imagine it doing anything other than adding mass to an area you really don't want it.
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Right now, the input resistor (R20) and capacitor (C22) spots on my Pearle2 are both empty (I soldered in little sockets for easy adjustment), so 57pF is the total capacitance. With a recommended loading of 100-200pF, there is room to play around with different values that I have on hand. Little by little.
So far, I've done a few of the major tweaks: external PSU with dual internal regulation (motor drive and control circuits isolated), tone arm wire and IC replacement, Ian's oil-well bearing with a neoprene washer underneath, and an Oyaide mat & weight. Next up is a vacuum-pump based record cleaner. The vacuum mechanism is complete and I'm looking for a donor table now.
So far, I've done a few of the major tweaks: external PSU with dual internal regulation (motor drive and control circuits isolated), tone arm wire and IC replacement, Ian's oil-well bearing with a neoprene washer underneath, and an Oyaide mat & weight. Next up is a vacuum-pump based record cleaner. The vacuum mechanism is complete and I'm looking for a donor table now.
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After living with the tonearm rewire and new RCA cables for a few weeks, the difference is just amazing! At first, I left C22 (cartridge loading) empty, so total system capacitance dropped from about 360pF to about 50pF. This was quite a change and my first reaction was "what happened to all of my treble?!?"
After letting my ears adjust for a little while, I realized what I had gotten used to was overly bright treble. The presentation, though, sounded a bit too dull for my tastes. After a week or two, I added 56pF in the C22 spot. This sounded better, but was lacking a pinch of sparkle at the top that I like. Another few weeks in and I am now running with 82pF in C22, for a total cartridge loading of about 125pF.
This sounds much better to me at this point and I am willing to leave it alone now.
After letting my ears adjust for a little while, I realized what I had gotten used to was overly bright treble. The presentation, though, sounded a bit too dull for my tastes. After a week or two, I added 56pF in the C22 spot. This sounded better, but was lacking a pinch of sparkle at the top that I like. Another few weeks in and I am now running with 82pF in C22, for a total cartridge loading of about 125pF.
This sounds much better to me at this point and I am willing to leave it alone now.
Thanks Stone Cold, so that is great its less than 50cm. I would have enough left over for the headshell leads then
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It's attached to the back of the arm wand to ground the wand.
I don't have a SL1200 I have an EPA100 very similar in the bearing housing. My arm was not moving correctly and had anti skate with the dial on 0. I found inside the bearing housing where the wire goes around the inside of the housing up into the arm wand there is bit of foam and double sided tape. In my arm these had perished and caused the wiring to move pulling on the arm. As the SL1200 is similar you mat find these as well, it's certainly worth looking.
I don't have a SL1200 I have an EPA100 very similar in the bearing housing. My arm was not moving correctly and had anti skate with the dial on 0. I found inside the bearing housing where the wire goes around the inside of the housing up into the arm wand there is bit of foam and double sided tape. In my arm these had perished and caused the wiring to move pulling on the arm. As the SL1200 is similar you mat find these as well, it's certainly worth looking.
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excelent post, but i need some help i recently bought a technics sl1950 the green and black wires where soldered toghether from the factory but thats a sort of self grounding, i replaced the rca cables because the left one was faulty and rewire as in this images sent the ground in naother wire from the original grounding point added the tonearm ground but no matter how i wire it whe i turn the volume at alf a 60 cycle hum its noticible how can i fix this?
First off, both cartridge grounds should NOT be connected togther.
They must go to seperate ground connections and to the independent ground shields of the output cables underneath.
The main chassis ground wire is also only connected to the chassis underneath.
Any other type of connections will result in a ground loop and hum.