Hi all. I rarely post here, but I should clarify the frequency response
curve on the VTPH-2A with regard to bass response and output loading.
From the VTPH-2A page on our website:
http://www.herronaudio.com/vtph2specs.html
"Frequency response: RIAA 20 Hz to 20 kHz ±0.1 dB at 10k Ohm output load impedance and higher.
Distortion: Less than 0.03% at 2.45 volts output at 1kHz at 20k Ohm and higher output load impedance (tube selection dependent)
Note: Lowest distortion and best performance occurs with output loading
at or above 20k Ohms - this gives the most dynamic sound"
The VTPH-2A has enough output capacitance that bass roll off is not an issue with output loading even with a 10k Ohm load.
We like very deep bass here!
The rumor of bass roll off got started years ago with a review where
some miss-information about the VTPH-1 possible bass roll off with load
was speculated but not measured in the measurements section of that
review.
Keith Herron