450 Pound Monobloc Amplifier

Power supply, power supply, power supply. You can't get around it, unless you get creative with switching power supplies. you need massive transformers (very heavy) and if sophisticated, massive coils (also very heavy). Efficient heat sinking is also very heavy. For low power amps that drive efficient speakers, you can design power supplies and electronics to output low power 10-20 watts and not have to have extremely heavy equipment. but for the others that have speakers that are difficult to drive or if you are designing and building amps that are designed to drive just about anything at rated power over the frequency range, you are going to need massive, expensive and very heavy power supplies. You can't get around it. Go to Nelson Pass' pass labs diy web site and read his thesis on power supply design. Again as mentioned in previous posts, compare apples to apples. What are you trying to drive? what power do you need? how efficient are the speakers you want to drive? The speakers that I have are absolutely wonderful sounding and are still better now (new panels) than many of the top of the line speakers I hear today. But, they take serious power to drive them. the mid and highs are amazing, and with the electronic crossover adjusted just right, the bass is pretty darn good. But, again, I need serious amplification to drive them. I have heard the Boulder amps. in my opinion seriously over priced, but so is a lot of stuff out there. But, the Boulder amps are absolutely wonderful sounding. I'm still not quite there with the Wilson Speakers. I've heard the Boulder system into Winson Speakers and Audio Research amps into the Wilson Speakers, and both into other top of the line speakers and it isn't the amps. It is the speakers. I'll take Boulder or Audio Research amps anytime. The new Reference 250 amps are great. But, Boulder is stupidly overpriced. However, there are people out there that are willing to pay the costs. More power to them. Anyway, the weight of the amps really depends on what they were designed to do and drive and the power supplies and coils and heat sinks, voltage rails (solid copper) etc. incorporated accordingly. Hence, very heavy amps.

Just my Engineering/Audio experience.

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The lighter amplifiers I have listened to are okay to great with efficient speaker loads at lower power levels. but, give them a difficult load or inefficient speakers and we have a problem. I prefer to not have to change my amps when I change speakers. Just me. When I move towards more efficient speakers, they better sound as good or better than the ones I now have and work well with my current amps. I can't see myself replacing all my equipment at one time. For me, I upgrade when I feel something is better than what I have sonically, I can afford it and I feel it is time for that upgrade. I am very happy with my system and amps although I have heard really nice amps, such as the Boulder amps and the Audio Research Amps, etc (there are more). But, jaw dropping differences? Well, no. Not jaw dropping. for me to upgrade to better amps, I would have to spend tons of money that I really don't think it is wise to spend right now. But, the Audio Research Reference 250 amps are really nice. I like the sound. So are the Reference 750 amps. It is also a long term issue with me for equipment. I know people that listen/demo once or twice and purchase, only to find out later that they should have listed/demo'd more before buying and they are really not happy with their new stuff over the older stuff. My favorite store in San Diego sells Audio Research, Krell, Boulder and many other amps tube and solid state. And they would let me take one home for a week or so to demo in my system before purchasing. 300 to 400 pounds would be a problem for me using my car, but it would be fun to find out.

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I don't believe that an amp has to be heavy to sound good. But, I do know to get rated power over the specified bandwidth, you need a serious power supply supply. you can't get around it. Which means that the tranformers must be huge and heavy. Large storage capacitors aren't cheap for the higher rail voltages necessary and they are heavy also. There are "tricks" that some manufacturers use, but they are just that, tricks. However, that is not to say that lower powered amps aren't wonderful. They are. One just needs to be very careful as to what they will be driving and what amount of consistent power is required. I read a review about the Dan D Agistino momentum amps and I would love to hear them. This guy, knows his stuff. I bet they are really great.

Kijanki: You will get no disagreement from me. At present I haven't heard a Class D amp that I really liked much. However, I haven't heard the New Jeff Rowland equipment lately. But, I have always really liked Jeff Rowland equipment anyway. Well designed and definitely well built.

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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.