Class D is just Dandy!

Not many Jeff Rowland owners have chimed in (Guido, aside). I have the (older, yet updated) 501 Mono's. The ICEpower modules inside have been taken from and early revision to the (presumably) latest (Rev J) as I bought them from Jeff in January (really not sure if its an upgrade - I had a bad power day in December and both blew).

I'm very much thrilled with the sound of the amps - yes, they are detailed, and very natural in the midrange. But what I've noticed (compared with my prior 'very nice' Audire class A/B dual mono) was the noise floor and, beyond my logic, the black backgrounds with LP's. It's like noise supression system on my turntable. I've gone back and forth - and something really magical happens in the treble. I hate that word "magical". I really do. But damn it. I can't explain it.

My next 'upgrade' will be the PC-1 modules. They are sitting in my music room, but I haven't installed them yet. I'm laboring through they very well documented, and necessary, breakin period. For those wondering, it's a bit like 7 stages of grief, with maybe 4 stages. Stage 1 - power on and a euphoric midrange, but not right. Kinda boomy but airy. Stage 2 - lack of midrange but bass rises. Stage 3 - bass is getting inline, and so it midrange. Stage 4 - OK...these are nice....

I would also like to hear someone chime in and give thier thoughts on the differences between the ICEpower ASP modules (like what is in my JRDG 501's) and the current crop of NCore modules. I'm really not looking to upgrade, but would like to hear from owners who have had both. Uhm - this may be directed at Guido :)

Boneman73, I think the word magical does apply because I was stunned how good my turntable sounded with my Class D amp, it never sounded that way before with a conventional designed amp. It just raised the bar on an enjoyable listening experience.

Back in 2008 I bought a Rotel RB1092; a Class D 500 watt/ch amp.  At the time it was the most expensive piece of equipment I had ever owned.  It served me very well until 2010.  I sold it to my B-I-L and was working 100% until I packed up after his death.  His daughter now has it and is awaiting me to come to Vermont to set the system up for her - I will wait until the fall for that trip.

miner42,

     Nice story except for the part about your brother in law dying!
     It just illustrates another less discussed benefit of good class D amps; reliability.  
     Most understand that heat is generally the enemy of electronics and excess heat can cause premature circuit or part failure.  Class D amps generally run so cool they don't even use heat sinks unless an analog power supply is substituted for the cool running  switch-mode power supplies (smps) typically utilized with, and even now built into, the
 class D power modules. 
     This lack of heat buildup, I believe, can only benefit class D amps and increase their reliability and extend their lifespans as a result.
     I also believe the opposite is true of class A and A/B amps specifically because they run much hotter..
     Great sounding, very quiet, very neutral, relatively inexpensive,very detailed and powerful amps with low distortion, wide dynamics  and very detailed from top to bottom.  What else would you want to consider an amp type ideal?  Oh yeah, have it consume electricity like a virgin consumes birth control pills, keep its cool like Clint Eastwood and, while you're at it, make it as reliable as Old Faithfull.  

     'Mr, Old Faithfull', Georgehifi, predictably would add that increasing the switching frequency to 3-5 mHz would make class D perfect  My opinion is that this may be making perfect the enemy of the extremely good.

      What the Heck, though, if it'll nudge class D firmly into the 'Ideal Amp Technology' consensus, the brains behind class D are likely pondering this as we speak.

      If Bostrom at Anaview/Abletec, Putzeys at Hypex or Hansen at Pascal determine that a higher switching frequency would actually benefit the performance of their class D modules, I would not wager against them incorporating this improvement into their products.

      Unfortunately, I'm not technically knowledgeable enough to determine whether a large increase in the switching frequency would actually improve class D amp performance.  As I've mentioned before, I detect no sonic detriments to the current switching frequency operating in the mid 500kHz range.  Obviously, though, I've also never been able to compare a class D amp with a switching frequency in the 500kHz range to an amp with a switching frequency in the 3-5 mHz range.

     I'm also a bit perplexed on whether and how this switching frequency issue affects the Bostrom/Anaview-Abletech and Hansen/Pascal class D modules' performance since they both now operate utilizing Phase Modulation rather than the Pulse Width Modulation still being utilized in the Putzeys/Hypex, along with being utilized in most previous, class D modules.

     Sorry to get so Geeky about this, but I've read and paid attention long enough about class D technology to be dangerous without completely grasping the subject.  I think it would help me if someone had the time, expertise and ability to explain this further in layman terms.

Thanks,
  Tim