Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Power supply upgrade

Sorry for the slow progress lately. All four PCs at home stopped working as Christmas approached, and I've been struggling to get them going again. If you're reading this it means that I've succeeded.

I have actually been putting a lot of time into the C61R linear PSU, but most of the work is finding the small bits and doing the mechanical work. The electrical connections could hardly have been easier - cut the old connectors off, strip the ends, and screw them into the FG connector blocks. Its very neat and it all works.

As you can see, I've turned the PSU upside-down and screwed the heatsink into the controller chassis - there's a bit of thermal paste squeezed out the edge of the heatsink. The effect of this is to create a more efficient heatsink, and the whole thing runs cooler now. I wouldn't like to guess the before and after temperatures, but I probably ought to try using some temperature tape.

However, because of the mechanical coupling, it runs noisier than before, and for the G68, I think I would prefer to use a larger supply that's running well inside its capacity. My experience so far is that they run cooler and quieter.

I suspect that a large supply under low load has low ripple as well. I tried running a few simulations, and other things being equal, a large rectifier capacitor allows you to use a secondary voltage close to the regulated output. In other words the ripple doesn't fall below the wanted voltage. I think this means a relatively smaller load will cause a smaller ripple ahead of the regulator, giving the latter an easy time. So whatever the reg's supply variation is, a larger supply will give a lower ripple. So the bigger the better, a la Naim.

Here's a few pictures of the FG 905 installation.











Nick