Hi gentlemen,
I recently methodically compared three amps,one expensive, and excellent amp, tubed with 8XKT120,the DEVIALET amp,which seems to be recognized as a top performer, and my SDS470 (mods:removed the asymmetric RCA input,removed the wire which allows the led included in the on/off switch to be lighted)(no mods of the caps).
The results show that the three above ones are in the same sound quality league, the differences between them being less than the magnitude when changing some cables.
The tubes one has an euphonic charachter, very pleasant,but after a (long) while,some lack of surprise appears in my mind, the DEVIALET is excellent, gives the impression that it's very quick and uncolored since the mediums are very slightly recessed, the piano notes are excellent,but if the digital message is not perfect,dont account on it to forgive .., and the SDS is fully comparable to both previous ones,the sound is absolutely excellent but under the condition all the cables have been optimized in order to tune as perfectly as possible the complete system.
I planned to upgrade the caps to panasonic's, but the current result is soo good that i dont intend anymore to do it.
I have NO personal interest for which concerns my information,i own (also) the tubed amp, so i have a free choice, and i choose the SDS, but i donot criticize the tubed once since it is really good also,but i am slightly more "disturbed" and awakened when listening to the SDS, this is why i finally prefer it..But other audiophiles might very well prefer the tubed one, this is in the subjective domain.
I formerly thought that the treble (or medium-treble) might be purer with the tubed amp, but finally the difference of purity is not really relevant, all is depending upon the purity of the digital system incl. the dac.
I will let all of you informed about future confirmations of the above conclusions.