[clpetersen]

Based on the posts in the 'Finally' thread as well as the 'Newbie' thread, and a suggestion to start a topic, here is new, hopefully short thread for a new proposed NC400 build.

Design: Stereo Chassis
Components:

2 X NC400
1 X SMPS600; per discussion with Hypex and others one is sufficient for almost all applications.
1 X  switching auxiliary supply, for the stand-by mode of the SMPS600.  Example: Retcomp, RAC02-05SC, 80-277VAC in; 5VDC out, 2W (~$12-)
1 X 12V relay; to turn on aux power supply when the external 12V trigger is removed (e.g. pre-amp turned off); example Omron G5V-1-DC12, a SPDT relay (~$2)
1 X Stereo Chassis - Example - SiliconRay stereo for NC400, silver faceplate
2 X indicator LEDs

Does anyone have another recommendation for a chassis?

Misc: balanced inputs (XLR) only planned, may add single-ended unbalanced (RCA)

FYI - the driven speakers have a sensitivity  of 90 dB and a mean impedance of 4 ohms (low of 3 ohms).

[Julf]

Sounds good - only question is why you would add RCA inputs? You would be better off with a (balanced) RCA-to-XLR cable, that at least preserves the differential/balanced connection along the cable.

[Speedskater]

When a XLR input is available, it's best to convert from an RCA output to a XLR cable as soon as possible.

[forkliftHIFI]

Don't add RCA jacks.  Just use conversion cables. 

[Julf]

Seems to be an echo here

[clpetersen]

Seems to be an echo here

I have an echo and a question -

Echo - looks like a lot of questions re: on/off/standby. I will summarize, corrections please:

1) On/Off - classical switch, IEC style. Required for safety and common sense, i.e if opening the cover. The switch should disconnect neutral and live (nominally white and black wires) but leave earth ground alone. This is the standard configuration of virtually all IEC switches.  Also a good place to add some fuses;many IEC switches incorporate holders for common 5x20 mm fuses. Size fuses according to power supply chosen and wall voltage.  For example, the 650 watt SMPS600 supply with 120VAC would require about 5 amps full-blast; use a 10 amp fuse.

2) Amplifier Standby - the nAMPON pin on the NC400 modules. Ground this pin to put amp in stand by mode. Simple  to use - no requirements on switch (i.e. voltage rating). Basically a manual operation, best for a front panel switch. See the Ghent Audio case for example.

3) Power supply standby - will put the whole system in standby, lowest power consumption (except full-off of course). This requires an active signal hence a small (1Watt) DC power supply, say 6-10 VDC. and a simple mechanical relay. These are both tiny and cheap. The advantage is that your preamp, if it has trigger function, can control the NC400 module. 



Question: I am planning to order everything for a holiday time build when I will have a bit of time.
What is the consensus on the low-voume listening performance of the Hypex design? Many positive comments on the large power performance; can't find much for quiet listening.

[Old_School]

I routinely listen at low volume, and can't say there's any detrimental effect other than the Fletcher-Munson stuff you'd get with any system at low output. I'm using Quad ESL63 speakers, and there's no loss of detail. The bass is obviously down at low volumes, but it's not the amps' fault.

They have so much headroom at low volumes my guess is that you won't hear any distortion.