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, If it were so funny for amp builders to use analog power supplies. You sure got that backwards. There is nothing that switches in an analog power supply. Nothing. It does not switch. It is like I said. The big caps hold a whole lot of reserve, and the small caps are there to fast feed the module.

B&O makes the A series modules so that talented builders can put their knowledge into improving the product.
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.
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