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2nd HiCap on an Nac 82 powers what?

D

deltaunit

pfm Member
Please could someone explain to me which sections of the pre-amp one and two *Caps powers on an 82?

As each *Cap has 2 power rails, if one *Cap is connected are these rails powering sections 1 and sections 2 independently and with both channels linked? Or is it left and right independently and both sections linked?

Then if both *Caps are connected does the first *Cap power section 1 with left and right on each rail and the second *Cap powering section 2 also with left and right per rail? Or is each *Cap powering just one channel left or right with 1 section per rail.

Just wondering how it works :confused:
 
I would think that naim would go for transient ability over stereo seperation,so with 1 hicap its would be one half for the inputs and one half for the outputs.
 
That's what I thought too for 1 Cap.

For two caps that would then presumably be further split so each hicap does either the front or back sections with each rail doing 1 channel each (of each section)?

Can anyone confirm?
 
I think you'll find the second psu, dosen't have to be a Hicap, runs the lights, the volume control and switching; it's quite amusing.....
 
Why then the HOO-HA about supercap superiority over the PS power supply for 82/52 Pre's? Asked from a point of ignorance, not attempting to be smart. :)
 
Gaius said:
I think you'll find the second psu, dosen't have to be a Hicap, runs the lights, the volume control and switching; it's quite amusing.....
Click to expand...

I don't think it does you know Mark, I seem to remember that the 82 comes with a small power supply to power the control board - separately to this, you can also use one or two Hi-Caps.
 
It's ridiculous for a preamplifier to have three AC cords (2xHC and 1xNAPSC). The 82 is a box fetishist delight. I know, I had one.

Bwahahahaha!
 
YNWOAN said:
I don't think it does you know Mark, I seem to remember that the 82 comes with a small power supply to power the control board - separately to this, you can also use one or two Hi-Caps.
Click to expand...

Indeed it did, and that's about all it did. Adding one HiCap was a revelation, as I recall, and the second just 'fiiled it out'.
 
E) None of the above.

The NAPSC runs the lights and relays. A NAPSC is required for 82 operation.

The 82's circuits are split ultimately into front/back. So that's [Phono(if used) + 729 stage ] + gain stage. One hicap powers all these for both channels when used; albeit with internal RC decoupling between each and every stage.

2 Hicaps make the fore/aft split happen. 1st Hicap powering both channels of [Phono(if used) + 729 stage ], one chanel per 24v rail; the 2nd hicap then powers both gain stages - i.e. provides separate 24v supplies to each. For the Naim module designs that's a significant improvement both theoretically and practically.

This 'fore/aft' arrangement makes good sense because channel separation is actually the least sensitive parameter by far - heck , most cartidges struggle to provide >>20dB separation, and vinyl is loved for its soundstage. Note the two independant regs in each Hicap guarantees >>80dB at frequencies of interest - far more than good enough, in fact a min. 10x better than you get from a dual-channel volume pot alone.

(Also note an 82 cannot use more than 4 of the 6 supplies in a Supercap. If Supercaps really do sound better it must be for some other reason)
 
Thanks Martin,

I thought I might get a definitive answer by posting this here at PFM and you didn't disappoint! Thank you for setting the record straight, it's nice to know a little about what is going on in there. :)

I'm using a DIYCap as one of my PSUs and it outputs a little higher than the HiCap - I just wanted to be sure it wasn't split 1 per channel...

I personally think the most likely reason the supercap has 2x outputs for an 82 is to enable an stepped upgrade path to the 52, which is fair enough I think.

I wonder if the benefit is in having a single transformer and 0v return? Perhaps the Supercap puts out a little more juice?
 
Each winding has its own 0v return to secondary, whether hicap or Scap. But, for example, a Supercap is also half the total pri:secondary leakage capacitance compared with 2 hicaps.

Play with this stuff long enough and you find you can make similar changes within other Naim preamps to good effect. I've very-lightly-altered 102s , which (driven off one hicap equivalent) have now displaced 82/Scaps in a couple of other people's systems. DIY means you can choose what is 'better'

(NB I go for 'measurement')
 
martin clark said:
E) None of the above.

The NAPSC runs the lights and relays. A NAPSC is required for 82 operation.

The 82's circuits are split ultimately into front/back. So that's [Phono(if used) + 729 stage ] + gain stage. One hicap powers all these for both channels when used; albeit with internal RC decoupling between each and every stage.

2 Hicaps make the fore/aft split happen. 1st Hicap powering both channels of [Phono(if used) + 729 stage ], one chanel per 24v rail; the 2nd hicap then powers both gain stages - i.e. provides separate 24v supplies to each. For the Naim module designs that's a significant improvement both theoretically and practically.

This 'fore/aft' arrangement makes good sense because channel separation is actually the least sensitive parameter by far - heck , most cartidges struggle to provide >>20dB separation, and vinyl is loved for its soundstage. Note the two independant regs in each Hicap guarantees >>80dB at frequencies of interest - far more than good enough, in fact a min. 10x better than you get from a dual-channel volume pot alone.

(Also note an 82 cannot use more than 4 of the 6 supplies in a Supercap. If Supercaps really do sound better it must be for some other reason)
Click to expand...

This is why you may or may not notice a substantial difference by adding a second hicap. If you are not using a phono card then the difference isn't that great.
 
YNWOAN said:
That's what I was thinking of :). The Hi-caps don't operate the front panel and remote.
Click to expand...

So this is what napsc does but many swap that out for a better psu or Hicap...

Or do we have the 82 with 2 Hicaps and a NAPSC and then a supercap with some of the previous...?

It's a lot of work and cost for an amplifier that can be bested by, say a 32.5 ;)
 
Gaius said:
So this is what napsc does but many swap that out for a better psu or Hicap...
Click to expand...

Might want to check with the factory before substituting just any power supply for the NAPSC due to voltage differences. IIRC, the regulators don't care for long-term over-voltages according to those in the know.

EDIT: I believe there's a warning about this in the naim forum archives.
 
dave said:
Might want to check with the factory before substituting just any power supply for the NAPSC due to voltage differences. IIRC, the regulators don't care for long-term over-voltages according to those in the know.

EDIT: I believe there's a warning about this in the naim forum archives.
Click to expand...

Dave you are of course right, many do it anyway and I was not advocating that.

Best wishes to you in Dixie. :)
 
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