Confused by ICE applications


I've started to get interested in the switch-mode power supplies, but I'm confused by how the various amplifier makers use them. My current investigation is into the B&O ICE modules and Jeff Rowland amps.

From what I can see on the ICE web page, they only sell complete amplifier modules. If that's so, what does JRDG (or Bel Canto) do with them? I'd thought that ICE would supply the power supply and the output stage was then up to the end user...
128x128macdonj
I don't think Onkyo uses an ICE module for its A-9555 class D integrated. Its damping factor spec is a mere 25, but you'd never know if from the sound in my rig. It's clean, tight, full, and extended. Anything but woofy or characterized by overhang. And I've been A-B'ing it with a VSP TransMOS 150, which has a damping factor around 1000.

In my rig, to the Onkyo's advantage (concerning damping factor) the woofers are a mere 5.5" in diameter, but to its challenge, one is augmented by a passive radiator and the other by a tuned port. Yet the bass is clean and totally tuneful.
Johnnyb53 - Onkyo is 85W and the smallest Icepower, as far as I know, is 100W/8ohm.

Damping factor is a little confusing. My Icepower has DF=4000 at low frequencies. Is it the reason for its tight bass? Atmasphere transformeless tube amps have DF=1.5 and very good sound.

Sometimes I get impression that sound is inversely proportional to specifications. Buying gear by good specifications is probably the biggest mistake.

As for small woofers - ask any bass player about bass rigs with good bass definition and he will tell you to look for stacks with a lot of 10" speakers. Larger 15" or 18" are also in use but have poor definition.

Few small speakers are far better than one large - just look at Dali Megaline design (perfect).
Amps with high damping factors can cause a reduction in perceived bass in speakers with limited low frequency capability. For example, when the midrange driver is also handling the lower frequencies.

The was an article at 6 Moons a while back discussing the optimum damping factor varying by speaker design.
Damping factor is not a ICEPower characteristic per se. There's been a lot of discussion of DF in other threads. DF is only one of a series of things to consider when matching a speaker and amp and maximizing the amp's ability to control the speaker's drivers. Some speakers need a lot of damping and others do not.

He's not going to tell you exactly what he does, but Rowland does a lot of things beside add Power Factor Correction to his latest amps (Continuum 500 and 312). He does enough that representatives from B&O have a hard time recognizing their ICEPower units. What matters is how well it works. Listen and hear for yourself.

Dave
Dcstep - My Rowland model 102 has two 200ASC modules inside (identical to picture in datasheet of 200ASC) and nothing else - just case. It is pretty much the same amp as Bel Canto S300 with different case. There might be some tweeking involved.