Thank you, Pierre.
Objective response : in Volt and relative gain in dB / frequency, from amplifier RKV-II, combo RKV-Wee and RKV-Verto
Combo RKV-Wee (unmodified)
Output RKV = Input Wee = 0.20 Volt (at 1 kHz)
Output Wee = 0.20 Volt x 50 = 10 Volt (at 1 kHz) (with 1:50 Wee transformers)
My results are as follows: for 6 distinct frequencies (250 Hz 500 Hz 1 kHz; 2 kHz; 5 kHz; 10 kHz). Voltage measured, depending on the frequency, in input of the Wee (and therefore in output of the RKV) with the Wee transformers 1:50 connected, and with for load an electrostatic headphones Stax SR-009 145000 Ohm of impedance.
Signal sinus 250 Hz : 0.205 V (relative gain : 0 dB)
Signal sinus 500 Hz : 0.203 V (relative gain : 0 dB)
Signal sinus 1 kHz : 0.201 V (relative gain : 0 dB)
Signal sinus 2 kHz : 0.193 V (relative gain : - 0.3 dB) (to compare to the +2 dB of Kevin Gilmore graph)
Signal sinus 5 kHz : 0.160 V (relative gain : - 1.9 dB) (to compare to the -4 dB of Kevin Gilmore graph)
Signal sinus 10 kHz : 0.115 V (relative gain : - 4.8 dB) (to compare to the -17 dB of Kevin Gilmore graph)
http://gilmore.chem.northwestern.edu/rkv.jpg
Combo RKV-Verto
Output RKV = Input Verto = 1.69 Volt (at 1 kHz)
Output Verto = 1.69 Volt x 5.9 = 10 Volt (at 1 kHz) (with 1:5.9 Verto transformers)
Signal sinus 250 Hz : 1.692 V (relative gain : 0 dB)
Signal sinus 500 Hz : 1.681 V (relative gain : 0 dB)
Signal sinus 1 kHz : 1.666 V (relative gain : 0 dB)
Signal sinus 2 kHz : 1.614 V (relative gain : - 0.3 dB) (to compare to the +2 dB of Kevin Gilmore graph)
Signal sinus 5 kHz : 1.354 V (relative gain : - 1.8 dB) (to compare to the -4 dB of Kevin Gilmore graph)
Signal sinus 10 kHz : 0.965 V (relative gain : - 4.7 dB) (to compare to the -17 dB of Kevin Gilmore graph)
http://gilmore.chem.northwestern.edu/rkv.jpg
Combo RKV-Wee (modified) (1:50 Wee transformers disabled)
Output RKV = Input Wee = Output Wee = 10 Volt (at 1 kHz) (without 1:50 Wee transformers)
Signal sinus 250 Hz : 9.980 V (relative gain : 0 dB)
Signal sinus 500 Hz : 10.00 V (relative gain : 0 dB)
Signal sinus 1 kHz : 10.00 V (relative gain : 0 dB)
Signal sinus 2 kHz : 10.01 V (relative gain : 0dB)
Signal sinus 5 kHz : 10.01 V (relative gain : 0 dB)
Signal sinus 10 kHz : 10.21 V (relative gain : + 0.2 dB)
And more comments : here : http://www.homecinema-fr.com/forum/post178219963.html#p178219963
Eric