Official M2 schematic

I've had the necessary parts for years and just last week I decided to build up a couple of channels to play with.
I'm wiring p2p, kind of M2x style, mainly because all I have on hand are small project boards buy having read the M2x thread, I'm also happy with the utility aspect.
My first front-end board is complete, using closely a matched lsk/lsj pair from the diyaudio store (within .02ma).
I used a Bourns 20R pot in place of the Jfet source resistors on a whim and have powered the board up and zeroed the offset at pin 7.
Everything looks good to me but I just wanted to verify...
The pot, after zeroing offset is at 13R5 for the 170 and 6R5 for the 74. Does this sound about right?

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yes ...but i prefer a SMPS with dual rail if i need it because i do not know how the GND is set at every ACA SMPS and what voltage potential you get if you build it together:
V+ GND V-

If you remove the cover of the supply you will see that the supply is surrounded by a metal shield that is connected to the supply's earth (and PE).
So to connect two power supplies like this won't work if both supplies protective earths is used.
 
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I'm busy populating Tea-bag's boards and went for the "R3, R4 hack" as described in post #2592.

But I'm unsure how to adjust the Bourns trimmer. Do I use a DMM? With the amp on or off? Need some guidance please.

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