View Full Version : Naim DACAP


mjroe
03-08-10, 04:22 PM
I’m thinking of building a weird power supply / DAC and mounting it in a naim shoebox style case & thought I’d share my thoughts here for discussion (and general ridicule) before I start.

I suppose it could be called a DACAP…

1. Use a NAP 90 as the donor case – remove the PCB but leave everything else.
2. Use the transformer 38-0-38 winding to supply a pair of SuperTeddyRegs to make the SuperTeddyCap side of the design.
3. I’d make a custom PCB for the above – although may also use SuperTeddyRegs prebuilt to minimise hassle. Layout the RC network though and routing to DINs etc.
4. Drill an extra hole next the current DIN hole in the case to act as the 4 pin power supply to amp DIN – a 5 pin dual power/signal DIN would go in the current 4pin DIN hole.
5. Mount an Arcam rDAC PCB on top of my custom made PCB ‘motherboard’ – jumper wires from the rDAC PCB to the motherboard so that the I/O can be at the back of the case.
6. Use the remaining NAP 90 transformer winding to provide power to a SuperTeddyReg to power the rDAC.
7. Drill a hole between the speaker plug holes in the case for the rDAC output DIN – no phonos.
8. Enlarge two of the speaker plug holes so that a SPDIF phono and TOSLINK optical connector can be mounted (PCB based).
9. The rDAC has a daughterboard with a selector switch and status lights, I’d reproduce this on my motherboard, connect it to the rDAC using a ZIF cable. The push switch could be accessed through one of the remaining speaker plug holes and the status LED or LEDs could be viewed through the other.
10. And now for the cool part, the rDAC input LED is red when no source is detected and green when present. I’d create a custom (but simple) circuit so that (by using a green LED backlight from Rapid and some red LEDs from Maplin) regardless of selected input the Naim Audio logo would glow red if the current input was not detected but change to the green when it was. So it would look like a NAP 90/140/HiCap with a difference!
11. I wouldn’t bother with a USB connector initially as I wouldn’t use it, the only thing I’d have to watch is that the rDAC may need shielding from the transformer – but I could test this by trial and error.

Think that would make a nice little shoebox Naimlike DAC and give me a good power supply for my NAC 72 too.

I've got a few different questions about the project, but I've split them off into different posts - so this one is really about the whole concept.

My motivation for the project is that I’m sure I could build a good power supply that would match my system for less than the £600 I predict it would cost to buy a HiCap and service it.
I’d also get to provide a better supply for the rDAC and house it in a more aesthetically pleasing Naim case. To be honest it doesn’t look that great looking all sliver and shiny on top of the retro looking 72…

The changing colour Naim logo would really float my boat though :D

Hopefully you’ve been able to follow my thoughts – I’d love to hear people’s feedback!