There was a scenario when Rupert Neve was called in by George Martin to a console that “didn’t sound right” to engineer Geoff Emerick at Air Studios in several channels - turns out there was a 3dB peak in the response at around 54KHz - this affected the harmonic response of the channels which made them sound different - it was due to capacitors being left off the output transformers which were part of an RC network to eliminate leakage inductance. Small things can make a big difference.
Not bragging at all. Most of the time I hear things should be easy. I rarely find things to be easy. Flat frequency 20 to 20k through a system. Easy! Few must actually check because my experience has been it’s not easy.
I service a lot of audio gear and I use a signal generator that goes up to 20 MHz to ensure that the LF stuff going up to 75KHz can be tested properly. I do console service to Neve, Harrison, Amek, MCI, Yamaha and so on and the hardest part is getting all channels sounding the same!
Amen, bro. IIRC, my function generator only goes up to 1 MHz....but usually good enough. To wander above 1 MHz would have to dust off my RF generator! lol
I get most of my test and service gear etc these days as Christmas and birthday presents from my wife. She gets jewellery! Hmmmm I wonder who’s winning there - maybe a new car
is a possibility.
I did build an RF multicore from a mic cable once back in the late ‘70s - 12 phase locked loops as FM transmitters at one end and another 12 as receivers at the other end - the red wire was the transmitter antenna and the white wire was the receiver antenna and ground was ground - I wanted to create a one wire multicore - unfortunately I never pursued the idea even though it worked.
I tuned one of my transmitters to the audio side band of the local TV station that some kids were watching in their lounge in the house next door and started to talk to them in a deep voice telling them “this is God speaking” - they called their parents in to hear “God” but as soon as they came into the room I stopped, as soon as the parents walked out I started again. We were in our lounge peeking over the windowsill in darkness so they couldn’t see us.
Yeah you’re right. Signing off.
Maybe the VU is falling off in response
I've been double checking with a Fluke 8060A and the roll off really seems to be there. It is complicated by the selected monitor position and a couple of other things. I have to go through things in a number of permutations before I'm convinced what I'm measuring is real.
Maybe try looking with a scope, see what you get before and after the 100ft run as well.
I don't have a single 100ft run or 10 cascaded active stages with a -3dB point at 50K. It's way more complicated than that. There is a lot of investigating to do.
