Technics SL-1210 Mk II hummy noise

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#21
Galu, you beat me to it. 🙂

dd.jpg

Picture from member of vinylengine
 
#29
Netlist said:
Nico, SL1200 is direct drive.
The transformer is normally isolated with rubbers.
But it wouldn't be the first I encounter to have been altered in all kind of ways.
Click to expand...

I think you're right here. I just took the transformer out. The rubbers are not decomposed but possibly harder than when new. Having put the transformer back and carefully re-tightened the screws I think the noise level is much reduced. Using a heavier rubber mat than the felt skip mat the deck came with improves things further.
I'll see if I can get some new rubbers. I wonder if some small damping on parts of the steel shielding would help further.

Thanks for your help!
 
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#34
Removing the transformer to outboard and modifying the PSU yields sonic improvements that are very real and quite noticeable. Highly recommended.

6L6

Thread 'Technics SL-1200 DC Power Supply'

This is my go at an external power supply for the SL-1200.

After a conversation with Wayne Colburn of Pass Labs, learning that he has made a few SP-10 PSU for in-house use, a few things became apparent - Get the bridge diodes out of the TT and just have DC on the umbilical. Use 1N4007 diodes, for whatever reason they sound the best, in this case even better than exotic high-speed diodes. Snub the bridge on the AC side with a .22uF film cap. Use multiple stages of RC filtering.

The biggest improvement is of course, no transformer vibration on the platter, easily done merely by locating...
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#35
I can't comment on the outboard mod, for I haven't seen one, but every time I see a modded 1210, it performs worse than the stock one in good condition.
You have no idea what people tend to do to these perfectly build turntables.
thinman65 said:
This is the type of transformer I have. Some of those steel parts look like they could resonate as they're not that rigid.
Click to expand...
If nobody messed with it, they should be fine.
thinman65 said:
The rubbers are not decomposed but possibly harder than when new. Having put the transformer back and carefully re-tightened the screws I think the noise level is much reduced. Using a heavier rubber mat than the felt skip mat the deck came with improves things further.
I'll see if I can get some new rubbers. I wonder if some small damping on parts of the steel shielding would help further.
Click to expand...
Unless your TT is very, very old, the rubbers will be fine. The original rubber mat should be used. A stock 1210 in good condition, with a normal good cartridge has no hum or hiss at all. I would say -85dB S/N ratio should easily be achieved. When cranking the volume of the preamp to its maximum, all you should hear is the hiss from the preamp.
 
#37
Netlist said:
I can't comment on the outboard mod, for I haven't seen one, but every time I see a modded 1210, it performs worse than the stock one in good condition.
You have no idea what people tend to do to these perfectly build turntables.

If nobody messed with it, they should be fine.

Unless your TT is very, very old, the rubbers will be fine. The original rubber mat should be used. A stock 1210 in good condition, with a normal good cartridge has no hum or hiss at all. I would say -85dB S/N ratio should easily be achieved. When cranking the volume of the preamp to its maximum, all you should hear is the hiss from the preamp.
Click to expand...
There were no obvious modifications to this TT when I got it other than the earthing being put through the signal grounds, which I've reverted back to the standard separate earth wire.

Also, I agree about the rubber mat - that does help but this TT is still noisier than other 1210s I've used which, as you say, I've found to be very quiet as standard.

I can only assume some age factor has affected the transformer.
 
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