long runs - i/c, spkr cables

Manufacturers will usually quote specs over the range 20Hz-20kHz because that's the norm and ideally you want the response flat within very tight limits over what is the audible range for most people.
However you'll often find that if you slacken the the spec limits slightly from say +/- 0.25dB to +/- 1dB yo can push out further - usually close to DC at the low end and out past 30kHz if using sample rates over 96k.

I've never used the M1 but have used the cheaper V-Dac which was excellent. MF seem to have a good digital design team at the moment so I'm sure the M1 will be excellent.

For used sales, in addition to the usual eBay, the PFM Classified section is excellent as are the equivalents on the other two main uk audio forums Wigwam and Art of Sound.

 

Thanks.

Those classified sections are really busy, with lots of people selling stuff they've only owned for six months...

it would be nice to stumble upon a bargain, but it looks like there's not a massive drop in price from new for a lot of kit.

Thanks for all the tips.