SL-1200 DC Power Supply DIY

Quote:

---

Originally Posted by 6L6

30v AC rectified will give you 40v DC before the filter bank. The bleeder won't make any difference. What value did you use for the filter resistors? And please post some well-lit, in-focus photos of your PSU please, can't help without them.

---

Dear Jim,

I attached the pictures in this post... As you can see, I changed the bleeder back to 1K. I made the serial connected of 2 secondary transformer to get 30v and I have 37v AC before diode bridge.
Attachment 27173 Attachment 27174 Attachment 27175 Attachment 27176

All those connections look good. How is the bridge connected to the caps?

Quote:

---

Originally Posted by 6L6

All those connections look good. How is the bridge connected to the caps?

---

Thanks Jim, I tried to copy from your schematic and pictures.

As you can see on the left hand of the picture I attached, the red wire was connected to the output positive pole (+) of the diode bridge and the white wire is connected to the negative pole (-) of the diode bridge. I am at the office now, so I can not take a picture. Sorry about that!

Attachment 27177

After so many years I'm finally planning to do power supply mod. It will be one with own voltage regulation (with tracking pre-regulator configuration). I'm reviewing multiple threads on the topic. And I have one doubt. Everyone I saw was mentioning 21V voltage on regulator output while Technics service manual states 20V. So why to use 1V greater value. 5% it's not much so probably should not hurt but why not to do just 20V?

Attachment 27851

Never mind, I found it. Newer manual for mk2-a version states 21V.

Almost 10 years later I managed to finish the project to my liking...

Here is my latest PSU and reg

The PSU is a plain full wave rectifier, followed by the quasimodo snubber, and then a CRC filter. I reduced the last R in Jim's CRCRC to 1R since the 10R was starving the electronics while breaking.
And I moved the last RC close to the regulator and inside the TT

The regulator sits on top of the input hole of the TT, offering an easy place for a DC socket (currently using a plain RCA socket)
I also added a PPTC and currently experimenting with a TVC for extra protection

The rest of the regulator follows Jim's design, apart from an extra 100nF ceramic at the input (as specified in the datasheet) and some quality of life parts like leds for easy monitoring, test points for the voltages around the regulator and a choice for a screw terminal for easier experimentation

Attachment 31435

Attachment 31433

Attachment 31434