300B SET or EL34 SET

Something else to mention. 

At low volume levels I believe it could be more important that your speakers are good at that volume. Not all are, some need medium volume levels to start sounding alive.

My very best listening setions are at night, with low volume levels (everyone is sleeping). The AC current is so clean that I cant believe the sound of my system. Incredibly engaging. 

@plga
Which speakers do you have?
My ATC SCM19 doesn't come alive before the volume is to high for me. That's why they are in the closet now. 

Check out Audio Mirror 45watt SET mono amps. 6C33C tube based. I have these and really like them. In my system they brought a whole new level of performance and refinement. You can roll input tubes to customize the sound and the power tubes are inexpensive. Vlad was great to deal with. 

Hello @simna
My speakers are the Q Acoustics Concept 500 floorstanders.
I've been told by a couple of dealers who sell them that they think the C500 are the best you can get at that price range and even for considerably more money. I know its about personal taste, but both dealers sell a LOT of brands and they have tried and sell many different speakers from every price range. 

I would check reviews on the Line Magnetic LM-518IA, the smaller brother of the LM-508IA (wich I have).

Some reviewers like Tim Smith from Wall of Sound and Herb Reichert from Stereophile, not to mention some forums on the web, rave about this 300B/845 integrated amp (the LM-518). Tim made it his reference amp, over many he had auditioned.

On the other hand, everyone who has heard both amps, the LM-518IA and LM-508, prefered the latest for being more dynamic. Thats why I bought it and its one incredible integrated that you can later also use it as power amp adding a good preamp and taking it to another level.

I have to admit, 300B and 845/805 tubes are considerably more expensive than EL34, but they also sound better. 

Its fair to mention that when I mean speakers coming alive, I mean balanced, dinamic and transparent at low volumes. 

You wont get your sofa vibrating like a thunder, but you will hear a beatiful presentación at low volumes. 

It also important to repeat what Jim Smith, a well known expert in audio and the writter of the book "Get better sound", wich I recomend: "I have never heard ANY system - no matter how great, no matter how expensive, no matter how deep the main speakers are claimed to reach, that did not benefit from a properly integrated pair of subs". 

A nice pair of subs are A MUST on a good stereo system.