Although I didn’t go to The Institute for Audio Research, I did look at the class materials. Good old Al Grundy had you go through all these sorts of systems engineering problems. Sigh.
At 1ft between each device the cutoff is at 55GHz
For 600Ω 4.65GHz
Rolloff is around 549KHz
The more devices in the chain the greater the downwards rolloff - it depends largely on the rolloff slope for each device as to how far down it all goes at 20KHz - but I think there’s a bandit device in the chain which could cause this. Old caps - the bane of my life! When I’ve been putting a pile of stuff in series for mastering including D/A outputs and A/D returns there is not usually a noticeable dip in HF response. But any gear that needs recapping becomes obvious when you start including it in a chain as it affects the following devices and colors the preceding.
Agreed. If there’s a significant drop then there should be a crook device somewhere in the chain. A small but acceptable drop is what I would envisage correctable by EQ prior to or in the chain - it should have a very shallow curve at that frequency. For working off tape it does become important to have as much of your HF unaffected as possible. I started out when the only medium was tape, no digital - it was only on the stuff I worked on doing my apprenticeship at Philips - I worked in a division of Philips on the first laser disc video players - 12” laser discs back in 1971 & 1972. The tape world in studios was about getting as much top end onto tape as you could because then tapes were mainly running at 15ips - when 30ips became a standard the HF loss problems started to fade.
The worst that can happen if you start mucking about with the compensation caps is oscillating circuits feeding capacitive loads. The value best suited is dependent on the capacitance of the load.
