SL-1200 DC Power Supply DIY

[6L6]

Cheers mate! It looks smashing!

[jmartinbaugh]

Hi I have A SL1210 Mk2 which I am fitting an external PSU to. I have found that the Target lamp bulb has blown and was thinking of replacing it with a LED. They show how to fit a LED using a +5 volt T020 regulator and a resistor to get the right voltage for the LED. My question is will this cause power supply noise or would it be OK if the voltage re was smoothed. can nyone suggest a circuit?.

Many thanks

[bobjan]

Hi. I'm new to this forum and am just starting to modify my SL 1200MK2. I see this is an older thread, but wasn't sure whether to post here or start a new thread. So I'll post here 1st and see what happens. I'm just starting to put together this power supply as well as the associated regulator. As for the regulator, I see that the ground would go to the screw on the left. I was wondering which terminals on the board to connect the Input (red wire) and Output (white wire ) of the regulator to? I couldn't find a clear schematic of the various boards in the turntable online. I found a service manual, but the quality wasn't that great, and I couldn't make out things that clearly from the images. I also was wondering about the voltages. The voltage drop for the regulator seems really high -- over 40v to around 21v. In most articles I see they talk about keeping the PS voltage to 7-8 v above the desired regulated voltage. Will this larger drop that's required put any undo stress on the regulator or does the design nullify any problems? I can build almost any project from the schematic, but I don't know how to design them and don't fully understand all that's going on. Thanks in advance for any help

[6L6]

This thread is fine.

I would suggest making the off-board PSU first, making sure it's operative and good, then adding the new regulator.

Don't worry about the dropout, it's not an issue. And if you do want to worry about it, you can always use bigger filter resistors to drop a few volts.

The regulator information is all here - http://theartofsound.net/forum/showt...311#post467311

Check your PM

[dimkasta]

I just installed the 317 reg using 10+8.2V zeners, plus one 1N4007 giving 20.2V in total

The result was less pronounced than when I moved the transformer outside and added the CRCRC filter, but still, the difference was big.
Especially in spatial information, stage depth and imaging.

Next step to try adding the tracking prereg

[dimkasta]

I installed the tracking prereg thingy yesterday

A small note... DO NOT leave any 317 without heatsinking. It will get HOT!!! I burned my fingers trying to find out why it could not maintain its speed after a while...

DSCF0775.jpg

On the difference side, there does not seem to be a significant improvement. Definitely some more spacial info and some more harmonics in there, but certainly not as big as getting the transformer out or replacing the reg.

[337alant]

Dimska
I intend to use an Avondale TPR2 in my 1200 its small and comes on a copper heat sink should fit nicely in the old the transformer bay
http://www.avondaleaudio.com/TPR2.html

I already have an external power supply that I use to power my Young DAC so I could just use that to experiment with?.
Young Dac power supply by 337alant, on Flickr

Alan

[dimkasta]

If the supply and reg can provide the required voltage I see no reason why they would not work.

I have not used them though, so I cannot say how well they would work even if they are within the V requirements

[337alant]

Dimskasta

Its an adjustable reg same as any LM317 so it just depends on the input voltage I have an 18-0-18v transformer on this one and the TPR2 drops out approz 5v so so its good for 18- 20V @ 1A if thats enough?

Alan

[6L6]

I'm honestly a bit disappointed to hear that the tracking prereg didn't make very much difference over the referenced 317, but not entirely surprised either... The short-term wall variance is being well handled by the 'big, dumb' approach of the huge caps and filter resistance in the PSU box.