My new SymAsym PCB design Rev_1.3

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It's a long time ago that i purchase 3 symasym 1.3DTV Board....1.4 version was also provided since. For a couple of day i founded in a industriel rubish some parts nice parts i could use for 1.3DTV so i decided to go for.

The first part was, comming from an industriel power supply, a nice EI trafo. Visualy i could say i rate over 600Va (steel dimension are w150xh130xd80mm) and 29-0-29V




I founded nice smoothing caps too 15000µF/100V. I took out of my stock somme rubish heatsink (300x75x40mm) to constitute the base of a stereo symasym 1.3 DTV bloc.
I will take two heatsink per chanel and join them with a 10mm thick sheet of aluminium. The little front heatsink on following picture will host 2 MUR20W Rectifier bridge.





I have also 2SC1837/2SA4793 and matched MJL1302/3281, 2SK170BL. So i need to purchase 2N5401/2N5551 and match them and some minor electronic parts for building

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My symasym is taking shape

Greetings all,

I thought I'd share my 1.3 DTV build progress with you all and get a few questions answered.

I used LSK370 because I had them from another project. I even remembered to reverse their direction on the board :p

I'm running off 27v rails; a bit low, but I think it should be okay.

I made an error in my parts order and ended up short a few caps. You can see my replacement in the first picture below (hint: it's bright yellow).

On to my question. In the assembly instructions AAK says to connect one of the on board ground pads to the heatsink. Instead of doing this I was considering connection my CT to ground (maybe through an NTC thermistor) at the terminal block. In my mind this creates something of a star ground. In the photos below CT is the blue wire. I still have to run ground from the IEC to the block and ground the chassis. Thoughts?

I will be posting more pictures when everything gets up and running.

Thanks all,


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