DIY Dual-Hi-Cap question

[MJSM]

Hi all,

I built a dual Hi-cap from a full width case Hi-cap plus spare Talema transformer (all employee sourced), and a pair of AWSR boards that I had fitted to another DIY power supply (link below) and in the current system I have a 'spare' Hi-cap effectively. I have a question about connecting this to a NAC 82.

According to Naim manuals, a NAC 82 can be powered by one or two Hi-caps, one or two Flatcaps, or a Supercap. I was wondering what is the collective opinion about connecting my 82 up to both the Hi-caps in my single box dual Hi-cap, e.g. is it a huge improvement over a single Hi-Cap, and more importantly is there any reason I shouldn't ??

My thinking is that with two separate Hi-Caps or Flatcaps, it is essentially the same as my single box (note that the only shared components are the incoming supply cable and the on/off switch, the LED at the front is powered by just the one Hi-cap obviously).

Would really appreciate any general points of view and real experience with a dual Hi-capped 82 especially.

https://www.dropbox.com/s/q1pnmxivih0bpod/DIY HCAP.jpg?dl=0


Cheers

 

[DuncanF]

I had an 82 years ago. There is definitely an improvement to be had with 2 x HiCaps, which I how I ran mine having started off with 1 x HiCap. And even more improvement with a SuperCap. Never could afford one of those though!

We are talking 10+ years ago, so memory is hazy, but ISTR more/bigger/wider soundstage was the principle improvement for both upgrades.

 

[DaveMc64]

I have an 82 and it is improved by two supplies. Be aware however that when powered by two supplies, the 82 splits it so one socket powers the left channel and one does the right channel. One of the two outputs from each Hicap (or whatever) powers the main gain stage for that channel (plus the output relay I think but not positive) and the other powers everything else, again for that channel. Not a problem when you're building your own power supply as you can wire the output sockets how you please.

 

[MJS]

No, the NAC82 doesn't do Left and Right from 2 different hicaps. The split is that the second hicap just powers the gain stages whilst the first one does the remaining circuitry - that is the tape buffers, input buffer/filter and the phono stage.

 

[DaveMc64]

You had me doubting myself for a minute so I've opened up my 82 and it does do the split left right.

In detail: yellow/black from ps1 powers gain stage 1; yellow from ps2 powers gain stage no2. Red/blue, white/black, grey/black from other ps1 power goes to the other buffer stages with white/black being the ta buffer. Similar for the second power on ps2 socket with solid white powering the ta buffer.

 

[MJS]

You're right - I was doing it from memory but I've just checked. One rail of each hicap is dedicated to the gain stage, not one hicap doing both gains.