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ALWSR Best wiring practice inside NAC 72

Mynamemynaim

Mynamemynaim

38yrs a Naim owner
So I have successfully finished all 6 alwsr boards
Two have gone into my DIY hicap (stepping 37v down to 31v)
These then feed into the 72 via a Mr Tibbs modded cable (two separate earth's)

At the moment (as it's a trail) the two regs in the hicap feed two more regs inside the 72 (31v down to 25v) and these regs are connected to the original PCB via the two positive rails (at the back of the board)
The two negatives are (again for the trial) (1) connected to the earth post (where the Mr Tibbs mod connects and (2) back to the original negative point on the din plug at the back of the case

So the question...what is the best place to run the negative back to (bearing in mind I will soon be throwing in the last two boards making 4 inside the 72)
The positives I will run directly to the (RSL) cards (by removing/isolating) the power pins on the PCB ...but where's best for the negative please?

Ps
(It looks an arse to connect to the centre PCB earth !! ...I don't really fancy doing that ...and surely all points should go back to the hicap negative??


PPS
Huge step up in sound with the onboard regs
 
I have never seen an inside picture of this, so if you can post a picture I can work from that would be great.
Also I would attach all the grounds to the 72 earth pin (there will be a lot!)
 
So, in effect you have 3 levels of regulation to the RSL cards:

Hi-Cap ALWSRs > Internal 72 ALWSRs > RSL on-card Regs
 
I can put a picture up...but it will be a little crude as it's a lash up trial at the moment

Was hoping to avoid soldering more wires to the original Naim post as it's a little busy already!!

Perhaps I can run a separate earth/negative wire all the way back to the hicap clone?
Would that be a better way of combining the return wires?
 
Stuart Frazer said:
So, in effect you have 3 levels of regulation to the RSL cards:

Hi-Cap ALWSRs > Internal 72 ALWSRs > RSL on-card Regs
Click to expand...


yes....thats exactly it
but its the earthing return that i would like to improve on


some pictures






51225244865_d3dd4d8ef2_c.jpg
[/url]New by rock solid, on Flickr


[/img][/url]New by rock solid, on Flickr



51224170046_88812df539_c.jpg
[/url]New by rock solid, on Flickr



51224935659_6a4a831893_c.jpg
[/url]Alwsr by rock solid, on Flickr





51225244855_efed1810d6_c.jpg
[/url]New by rock solid, on Flickr



51225280740_c5a482a146_c.jpg
[/url]Mods by rock solid, on Flickr
 
I plan to put the other two regs on the middle right side of the mother board

There's just enough space to accommodate


So at present
One board returns to the din ground
The other board returns to the phono/Mr Tibbs mod ground
With two separate earth's going back to the hicap clone...
 
Stuart Frazer said:
So, in effect you have 3 levels of regulation to the RSL cards:

Hi-Cap ALWSRs > Internal 72 ALWSRs > RSL on-card Regs
Click to expand...

I believe this is what Kit did on his preamp and has recommended to me previously too:

ZapCap regs -> RSL in preamp regs -> RSL MusicPower card regs
 
I does and it doesn't, the Mr Tibbs separation of grounds makes it different, but you have a similar issue with needing to avoid ground loops in connecting up the various ALWSRs with the 72 star ground arrangement and the RSL cards and the Mr Tibbs fully split supplies ... you have called all the right folk to get the right answers :)
 
Pete MB&D said:
When I had my 62 with 6 regs in I ran a separate return from the regs back to the psu, it sounded best that way.

Pete
Click to expand...

Thanks Pete
I had a feeling this might be the correct way to go...
And it would surely be a lot easier to implement that trying to cram the returns somewhere on the 72...
So should these all feed back to the hicap transformer mains neutral ....or the hicap ALWSR neutrals for best results do you think?

Ps
I take it you removed either a pin from the mother board or a socket from a card ...for each of your local reg connections ....but also to gather up all your negatives? ...or did you still use the PCB tracks and then take the returns from there?
 
All returns to the hicap transformer centre tap 0v.

My regs where home made lm317 and lm337 voltage reference with all the returns separately wired back to one point and a fat wire back to the 5 pin din socket.
I had a 5 pin 270deg plug wired with 4 2.5mm wires, that was a very tight fit using drilled out plug body’s.


Pete
 
Pete that's brilliant ...

Let me get this right..
Were the reg returns wired to a central point in your 62....then one thick wire from there to the din plug (if so...why 4 wires in the din)

Then ...if one wire..did that go all the way to the transformer center tap?

Just trying to get the layout in my head
 
It would be best to connect all the 0vs to the din plug connection but it’s a bit tight so I used one thick wire connected to the 0v in an accessible place.

One wire all the way back to the centre tap between the smoothing caps.

Pete
 
51225949356_111af4ffd6_c.jpg
[/url]Wiring by rock solid, on Flickr


something along these lines then with the dark wire between the two boxs being a single thick wire....nice and simple?

(though I'm now thinking i should have yet another supply just for the nac72 relay delay board???)
 
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