Thanks Michael,

What I'd probably do is pre-drill holes for 4 zap cards, try two first,

It strikes me it makes sense to pre-drill holes for mounts and connections for 4 zap modules, even if only initially going 2-channel.  However this is only after reading your good notes.

Out of interest, what made you go for the rs 800VA as opposed to the 1000VA for only £5 more and just a bit taller?

Thinking about it paralleling the modules might be a bit of a pain for neatness, so 4 per psu is a sweet spot, although it would mean doubling the psu, xformer and iec costs.

One 4-ch amp can initially bi-amp the front mains, then once confidence and funds are available, a duplicate 4-ch could run the bi-amp trebles, starting with just one single module for running center, if it's such a leap from what I run now, as it sounds it might be.

e.g.

amp1:

Front left bass

Surr left

Surr right

Front right bass

amp2:

Front Center

Front left treble

Rear Center

Front right treble

This would ensure no psu interaction between the 1000VA for bass and 1000VA for treble with 2-channel music.

Hmm.   4-channels seems a strangely sensible number, although I'd probably plan one of the amps to become 5-channels to (passive) bi-amp the front center channel and to make it useable and re-saleable as a 5-channel 250wpc amp in it's own right.

I found this quite an interesting pwm history: http://www.psaudio.com/articles/sdat.asp

Review of the ps audio 500Khz design: http://www.hometheaterhifi.com/volume_9_2/ps-audio-hca-2-power-amplifier-6-2002.html

Also a stereotimes review of the Bel Canto eVo detailing class-T v.s. class-D http://www.stereotimes.com/amp102300.shtm

Any thoughts appreciated.

regards,

Rob.