450 Pound Monobloc Amplifier

New 650W Rowland model 725 monoblocks are only 54lbs (including fancy heavy case milled of single billet of aluminum). The key is power supply. Rowland uses quiet switching power supply (SMPS) that provides line and load regulation while traditional supplies are not regulated at all, noisy and require huge amount of output capacitors to hold voltage steady, not to mention gigantic transformer. Transformers in Rowland SMPS are small because they operate at higher frequency. Transformer that operates at 100kHz can be 10x smaller than one operating at 60Hz. Rowland operates at 1MHz. In addition it provides power factor correction, meaning it presents itself as resistive load, while typical power supply takes current is narrow current spikes of big amplitude increasing requirements for cable gauge, wall socket quality etc not to mention radiated noise.

My Jolida does 60WPC at 50 lbs and I like it. I've seen those Boulder amps at Goodwin's and they're adoreable. I think anything that expensive should be gigantic as it makes the owner feel better about everything although I do want to see the video of the owner listening to them when they fall through the floor...somebody please make that video. Thank you in advance.

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.

enjoy

Man, a 1500 watt Class-A amp must be one HELL of a home heating device!! Not to mention being able to cook yer bacon and eggs while listening to your system...

-RW-

Minori,
What you wrote is sensible and based on experience. Have you had the opportunity to compare these newer light weight designs to the traditional premium heavyweight you described? The bottom line is the sound quality.
I'm not convinced that the lighter amplifiers have the same true drive ability with difficult loads and provide equal or greater sound quality(I could be wrong).
Regards,