Myles B. Astor, PhD
Senior Assistant Editor
The DC resistance of the A90 is 4 ohms, so maximum load should start at around 40 ohms. Then increase slowly from there to get a proper HF balance with good LF damping. I was at 51 ohms for awhile which is the flattest with my preamp (Pass XP-15 SS), compared to 88k and 192k masters of the same album. When an album is a little too dull at this setting, I bump it up to 71 ohms, which is a significant jump with a rising high end. I also fine tune VTA during this cycle to match the general character and detail of the digitals.
I can't imagine using this cartridge at loads over 100 ohms unless your system somehow benefits by the extended HF. The cartridge sure isn't flat at those settings, unless something in the preamp is loading it further!
I too adjust VTA for each record unless it's just for background. Using an ET2 LT arm. Very easy to do and hear on this setup.
Hi, I have just acquired a new a90, it is mounted on a Terminator linear arm and has about 12 hours on it. Love the sound but am noticing a rumble when the tonearm fluctuates up or down in the least. On perfectly flat records there is no issue but almost no records are perfectly flat. Yes I could clamp but I am moving away from clamping, has anyone else experienced this?
VTA looks right to me, about level, VTF is 2.2, SRA, don;t have a microscope as of yet but using my lighted 7x lense it looks allright, azimuth is level across the plane of the LP tho I have not done any measurements for crosstalk to verify.
I can make an audio sample this evening along
It would be interesting to hear the rumble that you speak of..... Thanks!