Up to 700 kHz

Dietmar of Trinity Audio just shared an interesting observation and comment regarding the AE Super High End Audio show 2015...

During the set-up day of the HK show Touraj played a title from Count Basie`s “Me and You”, where I heard a tremendous brass section entry. That entry has an extreme fast impulse response. Now I am back in Germany and assemble at the moment PHONO Preamplifiers and so I decided to use my new Audio Precision Analyser to measure the exact frequency response of a TRINITY PHONO. 

My new analyser can work with Equaliser Curves up to 200kHz, instead of 20kHz of my “old” R&S analyser. So I calculated the inverse RIAA equaliser curve from 10Hz to 200kHz (Can easily be done in one second with a Laplace Operation). 

From the SPICE simulation of my PHONO I expected a 3dB cut-off frequency in the range of 700kHz. Unfortunately I could never measure this outstanding response with my regular R&S analyser. The currently measured frequency response from 10Hz to 200kHz shows an attenuation of only -0.35dB at 200kHz, which gives you in a first order system a -3dB cut-off of 692kHz!!!! And that at a gain of 72dB of the TRINITY PHONO Preamp. 

That is very close to the 700kHz which I have simulated. So I am done now. 

So any “speed” limitation in a PHONO system can only come from the turn table and the pick-up and Touraj had prepared an excellent “turn table, tone arm and pick-up” set-up for that show.