What amp to match with Spatial Audio M3 Sapphire open back speakers

Dear All,
Unfortunately, my intended the acquisition of Spatial Audio M3 Sapphires fell through as the seller ended up accepting a higher offer for his speakers.
So I'm back to the drawing board and somewhat disappointed as I was really excited at the prospect of owning a pair these dream speakers.
I'll be starting the quest from scratch but wanted to thank all of you for your very useful input and advice. If anything, I have learned more about this wonderful hobby of ours.

Best regards to all and happy listening! jlr261

Thanks very much for your suggestions, even if the high and low order harmonics part kinda went over my head...

One of the differences you hear in all amplifiers is how they make distortion. Solid state tends to sound bright and harsh relative to tubes because the harmonic distortion they make is mostly higher ordered harmonics. The ear converts all distortion into a tonality- hence the brightness of solid state.

Tubes tend to make a lot more distortion but it tends to be lower ordered harmonics- the 2nd, 3rd and 4th. The ear is less sensitive to these (the higher orders are used to sense sound pressure, so the ear is keenly sensitive to them, please note that the brightness of solid state is caused by a very small amount of distortion) but the ear does treat the lower orders as a sort of 'warmth' or 'bloom'; these being the most common audiophile terms to describe lower ordered harmonics.


Some solid state people object to this coloration (thinking its caused by frequency response error, which it is not) and the most 'colored' in this regard are SETs. Much of this coloration can be removed if the tube amp is simply wired fully balanced from input to output; this causes the even ordered harmonics to be cancelled. This is desirable if getting closer to the music is your goal. SETs can be really neutral too, but to take advantage of them in this regard you need a very efficient speaker, typically over 100dB.

Dear atmasphere,
Thank you very much for the clear and detailed explanation of the different harmonic distortion types.

I have definitely learned quite a bit today and shall integrate this information as I go about trying out and selecting components for my new setup.

I should have added if you have a tube amp or a McIntosh tube or solid-state amp the 2,4,8-ohm outputs, the 4-ohm outputs make the Sapphire M3's sing like no other. The 8-ohm tap sounds louder, but it throws off the wonderful balance tone of the speakers. Using the 4 Ohm tape you just have to raise your volume on the preamp a bit more, and you will also find you have more control over the volume level. With 8 ohms the M3's sound good, with 4 ohms exceptional. 

I should have added if you have a tube amp or a McIntosh tube or solid-state amp the 2,4,8-ohm outputs, the 4-ohm outputs make the Sapphire M3's sing like no other.

I suspect this is not correct. The reason is we have customers using our S-30 amp on this speaker and the S-30 has a rather high output impedance (and no 4 ohm taps as its an OTL). I've not heard this combo myself but Clayton (the designer) has- contact him to see what he thinks.