2. amps-preamps
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ICE amps need cooling?

I've been looking for an amp to power my Maggies and was doing some research on these ICE modules from B&O. While reading the data sheet I saw that the model 1000 that puts out 525 watts into 8 Ohms and 1,000 watts into 4 Ohms it gave a specification of Power(FTC) of 80 watts continuous. Now I remember back in the 70's during the receiver wars the FTC mandated that power ratings be standardized to something like "100 wpc continuous into 8 Ohms with no more than X% distortion" This was to stop all the unrealistic power claims of huge power output for a brief time under tremendous distortion. It made the playing field level so consumers could at least get what they were expecting. So I see that the ICE module has a power rating of only 80 watts continuous! Now that is a far cry from the 500 watts they are bragging about. Have all amplifier specs abandoned the FTC ruling, or is the ICE module just blowing smoke? The B&O site also stated that with heat sinks or fan cooling the power rating could go up. Most ICE amps I see on the market don't have any heat sinks or even ventilation for that matter. So are we all buying ICE amps that can deliver their stated output power for only brief times, and actually put out only a fraction of the power for any sustained period of time? I'm no expert and I just saw this today so I am asking the the members with lots of knowledge in this area to respond and please clear this up. Thanks.
koestner
muralman1
1,527 posts
 
Kijanki, thanks for the calm and reasoned response. As much as we want to believe the very talented engineers at B&O made the digital power supply to perfect the sound of their modules, the fact is they did it to shrink the package. There is no doubt the small size of their amps is their strongest selling point. These modules are finding their way into everything from phones to audio gear. Like their business report says, they sold more than a 100 million units last year. Audio amps account for just a tiny fraction of those sales.

Dcstep is entirely right. If you look into your Rowland, you will not see just a module in a box. There is other circuitry there to attenuate the sound to their liking. Same goes for the H2O.

Spectron says they don't use switching power supplies either. He won't say why, but I bet it isn't for conveniences sakes, or some easy way out.
eldartford
4,262 posts
 
Ah yes. Then there are batteries. Arguments, anyone?
kijanki's avatar
kijanki
3,575 posts
 
Muralman1 - I still don't understand why you keep calling switching power supplies "digital". As for them being suitable only for mass market and not for the audio (your original statement) your Henry Ho (H2O) released two amps with Icepower modules with built-in switching power supplies M250S and M500S. Alleluja!!!

The only other circuitry in my Rowland Icepower amp is tiny input board with differential amp THAT1200. If there are any modds to original Icepower they are probably done at factory level (modds void B&O warranty) and reflect desired "house sound".

Eldartford - Rowland was widely using batteries in preamps and wrote a lot of FAQ about it. Now he switched to SMPS (Capri). If there is any switching noise it would not be able to hide well since Capri's bandwidth is 350kHz.
muralman1
1,527 posts
 
Henry Ho has had ASP amps out for years now. They are a cheap offering for people who want the class D sound but can't afford the flagship.

His Fire preamp, a HOT class A design, is pristinely clear and dynamic. I know if Henry thought using an ASP module to create a preamp a good idea, then he would not have gone to the trouble designing a preamp from the ground up.
guidocorona
4,114 posts
 
Most recent JRDG amps use SMPS, including the 312 stereo, which is designed around the ASP1000 module. While 300 series amps have substantive cast Aluminum cooling fins, I suspect these may be more cosmetic than anything else, as the external temp of 312 never grows much above look warm. It is worth pointing out that at approx $16K, the 312's price point is not exactly consumer grade, yet Jeff Rowland determined that an SMPS front loaded by a PFC unit would yield a musical performance superior to that of the previous 302 model, which used a linear power supply instead. . . and I do agree with him. Issue 188 of TAS should just be reaching the newsstands. . . it contains a sidebar that I have written on the JRDG 312 amp--part of my review article on Vienna Mahler speakers.
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