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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
kijanki's avatar
kijanki
4,428 posts
 
Muralman1 - I said it's funny because they think power supply should not switch but the amp itself should - and both of them are the same thing.

On the other hand I don't think they are THAT stupid and have some purpose in mind. The obvious one is that a lot of buyers, like you, still believes in linear power supplies.

If you can come up with any technical reason against using switching power supplies in audio - please let me know.
muralman1
1,527 posts
 
Here's one. The digital power supply is noisy. My amp builder makes amps of
both modules. The newest module has cut distortion and noise by half. They
gave this module a different designation. There is a built in noise and distortion
filter in the module. It has to be there.

The analog power supply is just that. It operates just like class A in that it
contains all power that the module needs under any load and any loudness. It is
not an amp.

The ICE amp is analog, and not digital. Read their white papers.
kijanki's avatar
kijanki
4,428 posts
 
Muralman - I don't know how many times I have to repeat that - CLASS D IS SWITCHING POWER SUPPLY. Switching itself does not make class D or SMPS digital. Both of them are exactly the same thing.

There is very little noise in properly designed SMPS (my Rowland 102 has 110dB S/N).
Noise is at non audible frequency
This frequency is easy to filter out (that's why Rowland uses it in preamps instead of linear

AS for linear power supply - it is not class A. Class A is an active regulated supply while linear PS in neither active nor regulated (line and load). It produces 120Hz ripple in-spite of huge number of capacitors. There are good and bad realization of each technology but the fact is that linear one is unregulated.
muralman1
1,527 posts
 
Kijanki, B&O would find your notion the modulation process is the same as the switching power supply unit insulting, or more likely, hilarious.

Henry Ho, an advanced electronics engineer is quite capable of creating a power supply that has no measurable ripple or other distortions. The 250A module is built to accept any power supply. My sound is proof enough.

By the way, take a look at the graphs provided by B&O. They show a distinct advantage of the A250 over the ASP250.
kijanki's avatar
kijanki
4,428 posts
 
Muralman1 - yes it is pretty much the same. I have no idea why you call switching power supplies digital and amplifier analog. Both of them are analog (no discrete values) and both operate with PWM and feedbacks. Modulation process might be different but purpose of power supply is different - input value is constant and feedback keeps output constant. The issue that you raised was noise. Since both operate at the same principle (pulse width modulation) and the same power - noise product of both is the same and very easy to filter out.

Icepower doesn't even bother to filter amplifier's switching noise completely and leaves about 1% on speaker wires. This noise is not audible and can modulate the sound only on non-linear element. Tweeter is potentially one but only if membrane moves (it cannot at such high frequencies). It cannot radiate because it needs hundreds of feet of wire to create 1/4 wave antenna.

There is quite few amps built with 1000ASP module that includes built in SMPS (40 Amperes) and very good reviews.

Let me repeat again - SMPS are regulated (line and load) and can deliver a lot of current - each of 1000ASP modules have its own 40A SMPS.

B&O guys are audio freaks and would never design substandard SMPS to their Icepower modules. I would be happy to discuss it with them if they would find my statements "insulting" or "hilarious". I design electronics (including SMPS) and am familiar with Karsten Nielsen doctorate work.

As for Henry Ho - he might get very low ripple by using a lot of capacitors but you're paying for that and power supply is still completely unregulated same way it was designed more than 50 years ago. Class D was invented during demonstration of response of SMPS. Engineers claimed that SMPS was so fast that it could even play music. Since then SMPS got highly specialized as well as class D. Requirements are different since SMPS is unidirectional and holds constant output voltage but they both got quite sophisticated with a lot of high quality ICs released in recent years.
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