Part Two
Let me start by saying what sound I was trying to achieve. First the midrange must be sing along sweet without being fat or dark sounding, very clear and detailed without being thin or analitical. I want to almost see the whole instrument or person singing. The highs must be well extended without glare, shimmering throughout the hole sound not just a leading edge while still possesing the original attack. The bass must be powerful, tuneful, and controlled (I don't like the term tight bass if you played a banjo instead of a bass guitar you would have tight bass) full with good bloom without being to fat and slow. All this must come together to form a very live musical whole. I also like a big soundstage with well defined but not etched performers
. Now for the tubes.
Again I called Joe Fratus. I had Tele 12au7's in the line stage which were very nice tubes but I wanted a little more fullness and punch for my cd player. Joe sent me three sets of tubes to try a GE and an RCA 12au7 and a military mullard cv4003 called 8136. The Tele, RCA, and GE all had strengths and weeknesses that were tradeoffs but the mullard fulfilled all of my sonic criteria. It was the hands down winner. With this great triumph we went after the driver tubes in the Carissa amp which are 12bh7's. I had RCA's and Joe sent me a set of GE's and a set of Brimars he had just recieved and he said the Brimars were his favorites. The Brimars were called 13D6 and were truly fabulous sonically from top to bottom. The GE and RCA tubes were good but not in the same league with the Brimars. One more tube to go. In the Phono section I had Tele 12ax7's for each chanel and either An RCA 12ax7 Black plate or Mullard 7125 for the cathode follower all are keepers. The phono section has a tube power supply with one 6FQ7/6CG7 tube. I had RCA, GE, and Phillips samples on hand but I was hoping to find a little better top to bottom sound. This time Joe sent an old EI gold plate which sounds very much like a vintage Mullard, also a very well regarded Sylvania, and a very rare Radiotron tube he had just got in. The Sylvania and Ei were both wonderful when used with the RCA in the cathode follower and I could live happily with either one but the Radiotron was just in another league. The Radiotron with the Tele's and RCA Blackplate again fulfulled my criteria for sonic excellence. I had one other tube change in the amp. The Carissa uses 845 output tubes and I was using an 845M tube which you can find one from a good production run is a very sought after tube. It tends to have a very lively sound. When I tried my old tin plate Valve Art 845 I was surprised to hear much more natural timbers and a more realistic sound. So the Valve Art 845 now resides with the Brimar driver tubes and a Bugle Boy 6DJ8 input in the Art Audio amp.
The conclusion and my purpose for writing this in part 3.
