My head slowly needs a break.
I have tested 6V6 Mullard and 6K6 Sylvania.
Rectifier and driver tube remained the same.
6V6 Mullard: Amazingly good tube, was a bit bright in tone and could have been a bit warmer for my taste.
Plays very transparent, open and detailed and also very powerful.
Could benefit a little more oommpppff with 6SL7/5751 instead of 12AT7.
However, I can imagine that the Brimar Yellow T or even Footscray would fit well, as well as a slightly softer rectifier tube.
The midrange was very clear and distinct, the treble is a bit sharp, but I think the right pairing will do the trick.
All in all a very good 6V6 for Ultimate, I also think that it will probably work even better with the Mundorf than with the Vcap CuTF.
Because it will also help to play a little less sharp and a little warmer and detailed enough as well.
Sylvania 6K6:
Ouufff, I was expecting something from it but it has put the 6V6 Mullard in its place for me if I'm honest.
Especially if you listen to the 6V6 and then listen to the 6K6 you will hear direct differences.
It immediately plays more direct, dynamic, liquid, deep and far into the stage without the mid-range and vocals seeming out of place.
The vocals remain focussed and direct and the rest of the music caresses and massages everything around it.
In addition to the Visseaux, this is another pair that is absolutely worth the money.
Smoother is probably still possible with a 12Au7, the 13D9 Brimar brings a lot of amplification here that is already over at below 9 o'clock pot position.
Powerful tube for little money and very underrated.
6K6 should have received more attention because they play very strongly.
Partly better than high-calibre 6V6 tubes which are overpriced.
13D9 Brimar:
Since she was inside the whole time and was able to gain some knowledge.
It plays extremely clearly and distinctly, with very good bass, right into the sub-bass range.
The midrange is very emotional and smooth, you can close your eyes and feel the vocals.
The treble is slightly sharp, and I think it's down to the EZ81 Rft tickling out the last few Hz.
It will certainly be better with a softer Ez rectifier tube, and perhaps play a little creamier with a 6BW4.
All in all, the Brimar 13D9 is a strong driver tube, and reminds me a lot of the B309 in terms of sound. You should buy one while they're cheap, and they are a bit rare, the good thing is that very few people have them on the shelf.
I will buy another one in stock when I get the chance.
Overall very happy with the purchase, all tubes have not caused any problems so far.
And for the collection they are all an enrichment, each pair in its own way.
I'm also starting to have a good selection of output tubes alongside the driver tubes for every suitable moment.
). After your research per 
