So I got to have some fun the past couple days listening to a different system and swapping gear around.
A couple key points before jumping in to observations:
1) Ken's goal here is to leave his system alone as much as possible while still finding an amplifier that takes the overall system performance up several notches over his old Odyssey amps.
2) Ken likes the system more on the warm side of neutral, but listens to a lot of rock and roll type music. So it needs to have the punch, drive, and impact necessary to provide satisfying sound on that type of music as well as the female vocals and smaller scale stuff.
3) Ken's favorite band is Dave Mathews. So it doesn't matter what the system sounds like with other music. It needs to do Dave to Ken's standards or this whole exercise is pointless. So two of our test tracks for comparison were Dave Matthews Band (DMB) tracks. We also used some 24/96 Chesky sampler stuff.
On to the comparisons......
When I first arrived this afternoon, Ken was listening to his system with the Moscode in place. The Moscode was running RCA 5963s. Ken was running his Treasures in the Transporter and Tungsol round plate 6sn7s in his preamp. After getting acquainted with the sound, we started the swapping.
We hooked up the PS Audio Perfectwave DAC direct to the BAT VK-60. Source was the Transporter via it's BNC spdif output to RCA coaxial input on the DAC. Ken had mentioned that the bass was completely missing when listening to DMB the night before. I knew some of that was the Sylvania VT-231 tubes and some was likely the fact we were running his Ushers on the 4-6 ohm tap. So we committed the cardinal sin of changing two things at once. We changed to the 3-4 ohm tap on the amp and changed the 8 driver tubes in the amp to Tungsol 6sn7GTB 50's vintage. All kinds of drive and impact on DMB. We were listening at an average of 89-94dB. The BAT has more than enough power to drive Ken's speakers at these volumes, which Ken's says is louder than he ever listens normally.
We then swapped input tubes on the BAT. Out came the Tungsol and in went some '50's vintage RCA 6SN7GT clear glass. Big fat tone, more body, but not as open as the Sylvania VT-231s. All kinds of drive and bottom end impact. They actually had a touch more gain than the Tungsols. So I had to back off the volume a touch to level match back to the 89-94dB range. We listened to a number of the 24/96 stuff using these tubes because we were all infatuated with the tone and syrupy goodness.
I then wanted to prove a point about the tubes. So back in went the Sylvania VT-231s. Much more open and natural sounding. More real sounding vocals and better extension up top, but a noticable weakness in the bass. Not noticed for upright bass playing in the Chesky stuff. But definitely noticed when DMB was played again. Still much better than last night according to Ken. So part of it was the tubes, but a lot of it was the output taps on the amp needed to be changed.
Time to change the pace. In an effort to keep things as close to apples to apples, we left the PS Audio PerfectWave DAC as the DAC and preamp function with the Transporter feeding it digital SPDIF via coaxial. But we put the Moscode in to hear the difference between it and the BAT. We left the RCA 5963s in it to start. The Moscode immediately showed its differences. While the BAT had more than enough bottom end heft, it couldn't match the grip and heft of the Moscode. An immediate sense of more control and more punch. The glorious midrange magic was gone, replaced by something that was more incisive with more attack, speed, and detail. It just didn't bloom like it did. It was more technically correct. But not as intoxicating.
Next came tube rolling in the Moscode itself. Out came the RCA 5963s and in went a Holland pair of Mullard 6922 equivalents with a Phillips Miniwatt SQ gold pin 6922 variant for the inner tube positions. Much more gain than the 5963s. Volume had to be adjusted quite a bit. These were even more technically correct, while at the same time being a touch warmer. Speakers disappeared a bit more. The difference between the Mullard/Phillips combo and the RCAs was kind of like listening to a track on a CD and then playing the same track on a good vinyl setup. The soundstage was bigger, more 3 dimensional, the speakers completely disappear in a wall of sound, the dynamic range seemingly was far greater, etc. etc. etc. This was the most "correct" the system had sounded so far, hitting all the audiophile buttons about frequency extension, imaging, scale, dynamics, detail, etc. But it also completely shut off the side of my brain that was intoxicated by the BAT realness. I didn't really want to listen to music anymore... and it wasn't because I was or wasn't getting tired of listening to the same tracks for the 5 time. This was a sound that would entertain me as an audiophile looking for audiophile performance, but it would eventually make me lose interest and turn off the system. The BAT combo wouldn't do that for me. I'd keep listening with it in the system. The PS Audio/Moscode combo just didn't have enough tube love to keep me attached to it.
At this point, Ken was curious to hear his system components again. So with the same Mullard/Phillips combo in the Moscode, we switched RCAs from the outputs of the PS Audio to the outputs of the Mapletree preamp and we went back to the Transporter's tube ouput stage feeding the tube preamp into the Moscode. It was a let down for me. The soundstage collapsed and had much less front to back depth. The sound became much more anchored to the speakers and I could pick out the speakers for the first time since I first arrived and was listening to the first combo of gear. The individual instruments and voices became more cardboard cutout and rink dinky. Not good....
So more swapping ensued. We pulled out the Phillips SQ and rolled in a pair of older vintage 6N30P-DR super tubes. That transformed things quite a bit. More dimensionality, more warmth, more relaxed sound, all while actually having more detail and increasing the soundstage width and depth several fold. This was the best combo of tubes if Ken were to keep the Moscode and keep the rest of his system in place as is.
One more swap for the day. We pulled the Moscode and hooked up the Butler to see how it compared. Not the right combo in Ken's system if he was wanting to keep his Transporter and 6sn7 based tube preamp with his current tubes. It was too much of the same thing. So we swapped tubes in the Transporter and preamp to Tungsol. In some ways it went in the right direction, but it still wasn't up to the level of the other combos of gear.
What we learned:
1) the best combo of gear for me and Ken's neighbor was the PS Audio PerfectWave DAC feeding the BAT directly. Depending on the music you wanted to hear, tube rolling the 6sn7s in the driver stage of the BAT produced what was desired for the various types of music Ken listens to. Just keep a couple different octets of different vintages around and roll whatever tubes are necessary for the music you want to listen to at that point in time. However, the PS Audio PWD running direct to amp is not an option for Ken because he needs HT bypass. So at best, the PWD would just replace Ken's Modwright Transporter and run single ended into his preamp. We never tried this as again, I didn't bring the PWD along to tempt Ken with changing additional components in his system. Again, trying to keep the rest of Ken's system intact. The PWD was necessary to hear the BAT amp without the hum because the $7 Switchcraft RCA to XLR adapters I have are crap and I couldn't get the Cardas ones here before the weekend. Otherwise I wouldn't have brought it along at all.
2) The BAT amp has more than enough power as a single stereo amp to drive Ken's speakers to his loudest desired volume. The BAT also has more than enough bottom end oomph to satisfy for rock and roll music. It's not the same kind of scale as the Moscode. But it's more than adequate.
3) The one combo of gear Ken still needs to hear is all his equipment driving the BAT... hopefully with better adapters, we can accomplish that next weekend.
4) The Moscode, with the tubes we used, is the easiest transition for Ken. It fits nicely in his existing rack. Ken can use all his existing equipment (the BAT is going to need new speaker cables as his current ones aren't long enough to reach if he leaves the amp to one side or the other where one of his old monoblocks sat). But it's the more expensive option compared to a used BAT.
5) I think tubes are what Ken needs, but he likes the drive and low end grunt that come with a hybrid like the Moscode.
6) I've gone through a number of tube amps recently looking for something to tickle my fancy. I like the BAT amp. I think it's a nice design and it works well. I had forgotten how much I enjoy an all tube amp. I now can't wait to start listening to the custom tube amp project underway.....
Thanks for the hospitality, Ken. I enjoyed hanging out and listening. I also enjoyed the brownies
