Another stupid question - passive pre related system build

[CageyH-FX1200]

What's the advantage of a stepped attenuator in up the P50SA compared to the P50?

I was just browsing eBay, system building and realise I don't know how the difference relates to sound quality?
Is a P90 "better sound quality" than a P50 as it separates out the left and right channels?
How do people find adjusting two volume controls in practice?

The current theoretical system is as follows:

Passive pre - probably the P50SA or P90 (depending on the answer to the question above)
A40 power amps to start off with (recommended minimum input for my speakers is 40w)
LS3 cable in a split config with 6 or 7m run on one channel and 2 or 3m run on the other. (I need to measure this, but it's a rough estimate)

I am assuming that on the small, uneven runs of cable, I won't need separate volume controls?
That would be the start of my system, adding in either another set of A40 or A70 amps later, and adding an additional run of cable. Any issues in two runs of cable? The LS3 would be used for the treble, and I would probably go for LS5 for bass duties.

Please feel free to pick holes in the plan above, and point out the error of my ways.
The speakers are Cyrus CLS70, which may not be the best, but sound pretty good to my ears.

[Dr Bunsen Honeydew]

I always refer to the steps through the range as musically better, but gains in hi-fi terms as well.

There is nothing wrong with your plan.

If nothing was better then I would just make one amp and one cable, it would make my life a lot easier as well.

Split speaker cable lengths is not a problem apart from if/when you sell on.

[jammy395]

Just go for it Cagey - I think it will sound fine.....Let us know yer findings.

[Dr Bunsen Honeydew]

Obviously unsure - he is asking advice whether to buy NVA on AoS

[CageyH-FX1200]

I am unsure. I will ask anybody who will listen to form a balanced opinion.
If I can get an upgrade for the least amount of money spent, I'll be a happy bunny, but at the moment I have no idea on which way to hop. NVA is but one of many options. Obviously, everybody here likes it, or they would not be here.

[Daniel Quinn]

cagey , several posters including moi , don't own NVA .

[Dr Bunsen Honeydew]

I was just amazed at what responce you expected at AoS when you ask for approval to buy NVA. It's like asking the devil to recommend a good crucifix

[Andrew]

You can usually spot the axe grinders and grudge bearers on AoS from their comments. Most have a history that means they have an agenda.

Even still, they find it impossible to deny how great it sounds. Instead, they add some sort of caveat at the end, usually accompanied by some cable or piece of kit that that's been messed with by some baboon, passing said bodge off as the Doc's handiwork.

Next thing you know, all the other "vampires of Salems Lot" come floating out after dark to suck more blood and "the management" ensures the thread runs on until they have thrown the same old mud pies all over again.

I'd simply say look closely at the history and motivations of the person giving the advice.

[jammy395]

At AoS when you ask for approval to buy NVA. It's like asking the devil to recommend a good crucifix (Doc).

Brilliant

[Dr Bunsen Honeydew]

Just to clear up VC options. AP10H, AP10P, AP20, AP50 are fitted as standard with P50 potentiometer. P50sa is made with one stereo Takman Metal Film resistors fitted to a 24 step Blue Switch attenuator. P90sa is made with two mono Shinkoh Tantalum resistors fitted to 24step Elma Metal switch attenuators.

AP50 is the only integrated that has the option of fitting the P50 type stepped attenuator, as AP10(series) and AP20 don't have room for it.