my take on these brands’ sound (at their higher/highest levels) is closer convergence between c-j and audio research and less close convergence to pass labs
why?
big boy amps from cj and arc now are based on the kt150 power tube which has tremendous linearity and power (and sonic signature, when using similarly high grade output transformers)
but the pass amps are a totally different topology, using power mosfets and no output transformers, so while the tonality may be ’more similar to tubes than in the past’, in actual listening they are not really that close
the arc and cj amps take advantage of their tubed input stages (arc does some fet coupling in their driver stage, but still uses a tubed input stage) and pass of course does not, thus the pass will have in relative terms, a leaner, less diffuse, more exacting sonic signature than the ’modern tube’ sound from the other two, especially noticeable through the treble and mids
where there is more convergence than ever is in bass response, where the kt150-powered amps are better than ever in bass control (think 80, maybe 90% of behemoth solid state) but the highs and mids will still be portrayed rather differently
’converging’ does not equal ’converged’ in my view... not that close really in real listening