Not sure here. I don't have one anymore to check out. It has been so long since I've been in the circuitry of one of those. I just looked up a service manual. It was hard to find. This thing is made from all discreet devices. I'm thinking the primary sound comes from their pairings of transistors in the gain stages & possibly the caps like you're saying. Only nominal local feedback is used, so I think it is more the transistors and the way they're used in this case. The more I look at that schematic the more I'm amazed at how decent it sounded (as I remember for back then and compared to other equipment then). If you need this schematic, I'll give you a link to it.
I was playing with a soundcard scope propram awhile back and was comparing a square wave generated on computer to the signal through my old tascam mixer. Playing with the 2-band EQ would distort the leading and trailing edges. I wondered if the preamp section of the 330b had something like this going on with it's caps. It's dual bass and treble - a possible source of more phase variations, maybe
Hay, John ! I'm drooling over the construction of the Sound Tech. Certainly, looks like HP overbuild ! The old Crown amps I just know from the stereo days. Beyond me stuff. I should have a 700 deck, though, but I got the eBait shaft. I still have that item on one of my drives to look at. Funny, I just moved the 330b out.. In that setup, I had it in the pre-out/main-in jacks and could go into the EQ inputs direct to the amp(I only needed it once). The pre was bugging for the longest time with it's natural coloration - I like it, but not for my little lab : ) I moved in a Sanyo DC int. amp at 45w which gives me a hint of headroom over the little HK. I wasn't finding the amp(cheap) I wanted a couple years ago, so I got the HK to stand in. With the Sanyo I got the L, R, L+R, Stereo, Reverse switching I wanted. FM is still gorgeous on the HK