450 Pound Monobloc Amplifier

Mapman; No I haven't heard any class D amps with my Martin Logans. I would be very interested in hearing some. If Jeff Rowland amps are Class D, then I know he did it right. Switching power supplies are not new. They were/are used in auto amps because the voltage was 12VDC and to get the power needed without large current, you had to increase the voltage. P=IV=VxV/R=IxIxR. So, if for a auto amp you wanted 100 Watts, then 100=IxV and therefore, I=100/12 = 8.33 amps. Thats it! So to get stupidly high power out of auto amps, you need to step up the voltage to keep the current low and still produce high power. this eliminated large heavy transformers and storage capacitors. But, the drawback was that the switching power supplies generated a lot of noise that had to be filtered and this was really difficult to do. For home amps, the process is the same. They probably use switching power supplies with lots of large power transistors to eliminate the need for very heavy and expensive transformers. Otherwise, I can't see a reason to do this. You only need large heat sinks if you are operating in real class A. I.e. output devices biased on all the time at rated output power. That takes lots of amps and makes heat that must be dissipated. So, Class D, is to get the voltage up to a high level so that the current will be lower and to eliminate the large expensive transformers and storage capacitors. This is off the top of my head. As long as the power ratings at load along the frequency range is as advertised, I really see no difference. power is power. Either by high voltage and low current or low voltage and high current. But to drive say, 8 ohm speakers, then you need current for power. remember P = IxIxR. or lots of voltage gain for the outputs instead. P= VxV/R.

@ Minorl, very good point with your last post!,you hit my concerns on the nail head!

Thankyou mapman.

@ Guidocorona, My current class A amp retailed for $14,000.00 so I suppose $20,000.00 and down would be adequate!

Audiolabyrinth,

On an earlier post, you requested a list of class D amps that sound good. I am not, by any measure, an expert on class D amplifiers. I'm just a fellow music/audio lover who is always striving to assemble the best system I can for both 2-channel and ht playback. I've recently been reading all the forums and reviews on various class D amps.

I discovered the competence of class D by chance and as a result of a misfortune. My old Aragon class A/B 4004 broke down this past January. When the estimate to repair the leaking power supply caps was estimated at $300-500, I had a decision to make; should I repair it and get back the very good sound this 23 yr old amp had provided in my system for the past 10 yrs or take this opportunity to upgrade my system? Due to the amp's age, I decided to buy a replacement amp, either new or used. To further complicate matters, my budget was limited to $1,000 or less.


So, I was looking for a high powered ss (400 or more watts@4 ohms) stereo or pair of monobloc amps for less than $1,ooo. I knew this would be a difficult quest so I scoured the online markets and read various audio forums. The forums piqued my interest in class D as a solution. I eventually wound up buying a new Class D Audio SDS440SC stereo amp that puts out 440 watts@4 ohms that was priced at $630 with free shipping. I am more than pleased with this amp in my system(cd source, tube preamp and Magnepan spkrs).

I'm not ready to say the CDA amp is a worthy substitute in sound quality to your Pass amp. But I am willing to swap amps with you for a few weeks, months, yrs or decades if you'd like to find out.

I think we need to know your budget,preamp and speakers to properly list class D amps you may want to audition. Others will likely chime in with their suggestions as well. Also, I live just north of Indy if you prefer we make the amp swap in person.

Thanks,
Tim