Hello Audio Experts!
Well, happy days are here again; I got my FetValve 400R upgrade delivered!
I upgraded from a 350 '+' FV, the best sounding AVA hybrid before the 400R/600R (I didn't have the double die, but that was just more power?) Doing a direct comparison with the 350'+' amp is difficult. It's been a few weeks since I sent it in, and I had different tubes in the '+' than in the 400R.
That said, I think the 400R is such an advance that the improved sonics are obvious, even with the time delay. When I got the 350+ upgrade, I thought it had tighter control, especially in the bass. The 400R brings the rest of the frequency spectrum up to this same high standard. I'm finding the mids & treble to be more open & airy, more 'present' in the room, & more detailed also.
But the biggest difference to me is in the grip this amp has on the individual notes. Going through a few of my favorite disks, I noticed how the notes were shaped & formed. This amp catches the notes at initiation, holds them tight to the peak, and then keeps the correct form until the notes decay as they should. The amp is not a slacker: no approximation, no 'area' shots, no 'good enough'. The amp doesn't let go until the note is done, period. This 'corralling' of the musical energy gives the notes better impact since there is no leakage to diminish or spread the sound to where it shouldn't be.
Listening to HOT TUNA's "Hot Tuna", you can hear Jorma & Jack just bending & torturing the strings. The harmonica of Will Scarlett just floats. But whether the music is fast or difficult, the amp never gives in, never loses control for a moment. I then listened to a bunch of string quartets, & the subtle detailing came through fully. You could almost see how the bow was moving. Next up was "Time Out", 'nough said. The clean details, the amazing feel of the instruments, the mastery of the musicians was all there in extra portions.
One thing I haven't mastered when listening to music is the 'space' factor. I know my room & speaker placement aren't ideal, so I can't really hear when the guitarist takes two steps in that direction.... With the 400R the increased detail & realism improves my ability to place the instruments. I think this is because the music is so well shaped that the sounds seem to only come from the instruments. With less energy escaping from the notes, more energy seems to originate from the instrument, thus placing it better on the soundstage.
Back to the big picture, the resulting music is magnificent. That's my opinion, and I'm sticking to it. My wife got home the other night (voice scholarship, still sings semi-pro) & we listened to some music. I try to keep her in the dark about my audio spending, but she knew I had the amp upgraded because she sent it from her office. So, she said,
"That Van Alstine thing is pretty good, isn't it?"
"What do you think?"
"I think yes".
"Can you explain how?"
"Go to hell, bud".
Elizabeth doesn't know an amp from a dac, but she has great ears!
PS: Frank sent me a cool AVA flashlight...made in China!