Class "D" amp? I do not have a clue. Do you?

The problem with my speakers are they are 8 ohm not low ohms. My speakers suck down as much power as you can feed them. Most amps don't make power until you get into the low ohms.

Then I suspect that you Icepower having huge damping factor at low frequencies (about 4000) overdamped your speakers making very lean bass?

Coxhous,

ref1000 (10K icepower stock module input impedance) may not be an optimal mach in terms of input impedance for your tube pre-amp. That might be a factor in weak/poor bass.

ref100m has 100K input impedance specifically to perform better with tube pre-amps.

I seem to recall that newer Spectrons may have higher input impedance for use with tube pre-amps as well, more like ref1000m than ref1000.

Also damping factor could be a factor as well. Not sure about Spectron DF but BC 100m is >1000, which is very high and might produce lean sounding bass with speakers that do not benefit. Or it is possible that this particular flavor of highly damped bass may not be to everyone's particular liking. Then again, what is?

The OHM Walsh speakers in my system do benefit from high damping. The bass is more dynamic, cleaner and articulate than with the 120 w/ch amp I used prior with lower damping. The change was pronounced when I switched amps and sounded relatively lean at first, but that was a temporary illusion.

The difference in the bass with my Dynaudio monitors was significantly less noticeable yet also clearly present.

Bottom line is things sound more real and natural to me compared to live now with the BC ref1000ms in my system than ever before.

Also I do not feel that performance is lacking in any significant area now compared to the best reference systems I have heard recently.

I am always actively listening to establish new reference standards that I can target though, so we'll see....

Mapman - you're right about low input impedance. My Rowland has extra board (with THAT1200 intrumentation amp) to increase impedance to 40k.

Channel Islands D-200 user here. They sound just as good as my previous amp, run WAY cooler and weigh a lot less. My previous amp was a Pass Labs X250.5