Confused by ICE applications

Magfan - there is still some residue (about 1%) of 400 kHz but it is not harmful. Switching transients were already removed by output filter and 1% residue of 400kHz will radiate at 1/4 wave if speaker wires are longer than 615 feet.

Magfan,

The point you raised yesterday was the heart of my question. I'd seen the www.icepower... link and thought to myself: if everyone is using the same modules, won't the amps sound the same?

Kijanki and Dcstep have a partial answer: the lower cost Rowland gear is apparently similar or identical to the competition (say, Bel Canto); however, the higher cost Rowland gear has more modificaitons and may sound different.

I wouldn't expect Jeff Rowland to give precise descriptions of any modifications he makes to an ICE Power module when he uses it, but I would like a general sense of why his products are different than some other company's that uses the ICE Power units.

Macdonj, on the 312 and Continuum 500 one huge difference is the addition of Power Factor Correction. ICE and D can really spike the mains and cause harmonic currents that can be audible. The PFC presents a more sinewave-like load to the mains and eliminates the harmonic currents. Additionally, the PFC converts AC to 385 volt DC, giving ample, clean power to the unit. The DC operation also helps with quietness of the pre-amp stage, approaching battery power style low noise levels. (PFC can be added to most current JRDG products with his PC1 unit).

Add to that, dual-mono, fully balanced operation for the Continuum, short signal path lengths, heavy aluminum billet chassis, internal and external isolation from EMI and RFI and you end up with a total package that's beyond most of the competition. Jeff pays attention to each wire, trying different materials to arrive at what he considers the truest (most transparent) sound.

Jeff's chassis alone adds significantly to cost (even on the lower level 102, 201, 501 and Capri), but they aren't just things of beauty. They're functional parts of the RFI/EMI control scheme. With ICE and Class D this is very important because of all the energy given off by the unit itself. Combine that with a nearby CDP and it gets very important. My Continuum 500 and Playback Designs MPS-5 CDP are right next to each other in a tight armoire, with a gaggle of wires cramed in behind them. Despite all that potential, the system is almost dead quiet.

Jeff creates very elegant designs. Look inside his Capri preamp and you'll be amazed at how view circuits there are how clean things are. His phono modules are the size of the last joint of my little finger, yet they compete with Levinson, Sutherland, Manley, etc. for resolving capacity. The phono circuit is utterly quiet in my setup.

Clean and simple is a core philosphy to Jeff. He lives by that and it pays off in the results.

Dave

According to one of the editorial reviews (can find it) Bel Canto's S300 suffers thin lower midrange but after placing it on anti-resonance cones sound becomes fuller. Rowland's case is milled from billet of aluminium.

In fact, on the Continuum the large flat surfaces of the chassis are ridged, to refract sound waves in those cases where it might be close to speakers. The tolerances on the Rowland chassis are .003". The nibs and screw threads for mounting boards, etc. are machined in, to the same tolerance. Like I said before, the Rowland chassis is no mere cosmetic design exercise, even though he highly values esthetic appeal.

Dave