The VM-1a has 7 tubes and works ONLY with the 2 headphones I listed. I generally do not like tubes, but there are exceptions. With the Benchmark DAC3B, the sound is incredibly detailed, fast, and rivals the very best sound I have heard from ANY system (no room to contend with).
The CA-1a sounds like headphones on steroids, while the SR1a (called ear speakers) sounds like speakers attached to your ears. Stereophile will review the amp soon. I hope they use a very neutral DAC like the DAC3B.
With the Musetec 005 the sparkle on top is just not there relative to the DAC3B. If I did not have the DAC3B I may have been content with the VM-1a and 005 pairing but I lucked out hearing the DAC3B with the VM-1a.
Today I replaced, my CODA 07x preamp and put in the Benchmark LA4 preamp + Benchmark AHB2 monos + Musetec 005. Just stunning. Better than the DAC3B in this stack. I have to decide on some gear pairings for my office and this will be the final setup.
For my Livingroom I will get a second Musetec 005 + CODA 07x preamp + KRELL 175XD amp. I may sell the 07x to buy a second LA4.