stereo imagery, treble and boutique components

[YNMOAN]

I notice that one quite often reads posts regarding the improvement of stereo imagery and depth. The responses often centre around room setup and speaker placement. Now, whilst I would not disagree with such sentiments my experience over the last few years has slightly altered my view (I already use room treatments and have very carefully positioned speakers).

A few years ago I came across a chap making replacement circuit boards/cards - for my Naim pre-amp. These used the original Naim circuit but allowed for all the Acoustica mods to be implemented; I liked these a lot and thought they showed promise and a friend also bought a set. Now, my friend was very into component experimentation at the time and he tried a large number of different makes of capacitors and resistors to populate his boards. Each time he made a change that he thought promising, he brought them over to my house and we A/B compared his boards to mine (it is very easy to swap specific parts of the circuitry on the Nac72). If I also liked the change I made the change to my boards and so it progressed for a few months (I did not always make a change). At the end I was happy with the changes wrought. The upper mid was now a lot more open but no less dynamic; but the biggest change was in the way the very top end was rendered. This was now quite a lot more delicate and airy with significantly better tonal differentiation - but, the surprise was that the stereo imagery was significantly better. Particularly in terms of localisation side to side and instruments seemed to exist much more in their own acoustic space.

In the past I had thought that the ability to reproduce very low frequencies would aid stereo. When I integrated a sub into my system the sense of hall acoustic did certainly improve (as did apparent depth) but general imagery was not significantly altered. Now I wonder if it is not the way that the very final decay of a note is handled that does not impact more significantly on imagery in general.


Yesterday, I was reminded of all of this as I had just changed the loading on my phonostage. On the design I use this can only be achieved by physically de-soldering a resistor and a capacitor and changing them. So, I swapped a pair of Vishay bulk foil resistors for a pair of Charcroft resistors (that I was kindly given) and changed a couple of styrene caps for another pair of styrene caps (although the replacements were significantly physically bigger for some reason - despite being a smaller value). I didn't really expect much from this mod and half expected to have to reverse it. As it has turned out though, I am quite surprised by how much difference it has made. One again, I am particularly struck by the apparent subjective improvement in stereo placement of instruments. Sounds seem to come more readily from the speaker boundaries (and slightly beyond) and spacing of instruments in the foreground seems more pronounced. Ironically, stereo imagery is not one of the qualities I consider particularly important and I was happy enough with it before any of these changes were made.

I wonder if anyone else has encountered similar improvements to stereo imagery when improvements to the reproduction of the upper registers has been made?
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P.S. Just in case anyone senses a marketing conspiracy, let me make it clear that I am not involved in any way (financially or design) with any of the equipment or mods I have described.

 

[RobHolt]

I would simply say that better equipment allows for better imagery but my own experiments haven't revealed that better/different caps and resistors have any audible effect in themselves, other than parts with better tolerance ratings tend to perform better in critical areas such a phono stage. There will be certain cases of course where you wouldn't want to be using wire wound resistors etc in circuits for quite obvious and measurable reasons.

Naim amplifiers are quite sensitive to the PSU but that is due to the elderly circuit design peculiarities, though that's not necessarily a criticism. Other circuits aren't nearly as critical of PSU design - PSU design including decoupling capacitors at various points.

The last major rebuild for me (Quad 34 aside) was the WD phono stage.
That has the lot thrown at it - 0.1% caps in the RIAA section, PIO caps for bypass and coupling, fast diodes in the PSU, Black Gate PSU caps and some posh resistors the name of which escapes me. £200 or so of parts.
Memory when comparing such incremental changes is never very reliable but I had no 'wow that's better' moment after these mods.
You heard the stage briefly at Andrew's and liked it, but that's how it sounds as standard IMO.

So I don't rule out components altering sound, but there is always a good reason for it.

 

[YNMOAN]

Hello Rob, I thought you would find my tale entertaining

We didn't make any changes to the PSU or regulation - I had re-capped my PSU some months earlier.

One thing we did find was that the specific type/make of decoupling cap used made quite a clear difference (I know I'm in no way the first to suggest this). I'm not saying that changing a specific component will be a revelation. Hearing the differences was made a lot easier in this instance by being able to swap quickly (a minute or so) between modified and un-modified circuits quickly (using mute to keep the volume identical).

You heard the stage briefly at Andrew's and liked it, but that's how it sounds as standard IMO.

Yes I did like it - it had a very low noise floor as I remember.

 

[RobHolt]

Agree absolutely on the decoupling caps in Naim circuits. The circuit is sensitive and will likely respond to the differences between caps.

If you want to see how two nominally similar caps alter regulator performance, decouple an LM317 or ALW SR with a standard electro and then try it with a film cap.

 

[flatpopely]

I think that there is something more at play here as well than just better component quality. I believe that the correct loading of the cartridge, Troika, has enabled very, very, low level info to be transmitted to the phono stage. The previous impedance mis-match, although small, may have prevented the tiny info in the groove, that dictates soundtage and imagery, being replayed correctly.

Just a thought.

 

[YNMOAN]

Yep, I agree - the components I removed were already pretty posh; perhaps not quite as boutique as the ones I put in but still a lot better than most.

To be honest, my rambling tale has somewhat distracted from my original intention; which was to question the relationship between stereo reproduction and the subjective reproduced quality of specific elements of the frequency range (and not about particular makes of amp for example).
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The only fly in the 'it's not the components' ointment is this; I had quite a good reason for thinking that altering the input impedance of my MC stage would have little, if any, effect. You see, I use modified Naim 323 cards; the particular ones I use have had some of the components (capacitors) upgraded for supposedly better quality ones. When I compared these cards directly I felt they were slightly more open in the mid and sweeter at the top and so I used them. However, after a bit of investigating (not much really) I discovered they were set for Naims S loading and theory has it that they should be K loading for my Troika. As it happens, I also have a very late example of Naim 323K boards that have not been modified in any way. when I compared my modified 323S and unmodified 323K boards I could hear little difference and, if anything, I preferred the S boards - so I concluded that the loading was of little real benefit and have put of making this change for some time. Indeed, as I said earlier, I anticipated that I would have to reverse it and so was careful to preserve the components that I removed.

 

[sq225917]

What might make a difference is the tolerances, those Charcrofts were 0.01%, uber spec, and if i remember correctly we chose 2% caps rather than the typical Naim 10%. (I don't think the capacitive loading makes much difference to be honest, least not with MC).

I'll pop the snow tyres on and come round tonight Mark. ;-) I could bring the Uphorik...

 

[YNMOAN]

You will need those snow tyres - there is about 4.5 inches here.