How to DIY yourself very nice Class D monoblocks

Erik
Belles reference 150 v2 class ’B’ amp
David has started with a clean slate for the Reference series, and this amplifier bears little resemblance to its ancestors. The 150A Reference V2 is a Class B design that provides 125 watts per channel into an 8 ohm load,. Yup I checked again it is a class ’B’ amp. David has taken the Class B circuit used in the original 150 Reference amplifier, and has craftily applied his engineering savvy in order to tease a higher level of sound quality out of an already excellent design. I keep solid-state gear on all the time, and the Class B circuit design means that the amplifier is not an energy hog.   Fantastic amp. I do not think to many people can pull this off. Very good designer.

Belles reference 150 v2 class ’B’ amp

Well, that certainly IS what is claimed. Interestingly, and sadly, none of the reviews I’ve found explain it. I know of no class B circuit which allows an amplifier to operate without significant distortion through the zero V crossing point, which is why I said earlier it couldn’t be. If I was reviewing such an amp I would have made it a point to explain this.

I don’t know everything, and I’m not an EE, but this is now a very curious thing to me.
This is certainly the first Class B amplifier I've heard of with high end cred.

Best,
E

invictus005

I seriously doubt there's an SMPS in any audio amplifier that's as life threatening as the big linear supplies resting in the heart of any class A amp. I get accused of my F5 being easy to build. I at least stuffed boards and stuck probes into the thing. That thing takes nothing more than screwing boards into a box and running wires to a power switch and signal posts. I can't imagine it being more simple than that. That makes a Pass ACA look like rocket science, and those things are made for 12 year olds to build. 

I seriously doubt there's an SMPS in any audio amplifier that's as life threatening as the big linear supplies resting in the heart of any class A amp

What's life threatening is high voltages. It only takes a few milliamps to stop your heart. I believe that switching power supplies have much higher peak voltages than linear amps of the same power. In the 200-300V range. The amplifier portion itself runs lower. This is all quite fuzzy and old knowledge so I can be wrong.

That thing takes nothing more than screwing boards into a box and running wires to a power switch and signal posts. I can't imagine it being more simple than that.

And this is also true. Assembly is dead simple. Keep your fingers and tools out of the way when it's on, and be aware the caps can maintain a very high voltage even after they are off.

Best,
E

That's not my understanding of how an SMPS works at all. A simple SMPS converts mains voltage to DC and filters it a little. DC is then pipes into some kind of transistors, typically a FET, which is driven by an IC. The output side is coupled to the input side through a small transformer. Feedback from the output is fed back to the switching IC for overload protection and switching frequency moderation to maintain the output voltage. The output is filtered according to noise floor requirements. Unless the output demands high voltages, there's no reason for there to be voltages higher than the rectified mains voltage. No SMPS has reservoir capacitance like a big linear supply does. I wouldn't want to take 47uF at 150V, but I'd choose that over 120,000uF at 32V. 

People survive lightning strikes and thousands of volts in the form of common static discharge all the time. There's no arbitrary rules about volts or amp. A few milliamps can kill you with enough volts and a few volts can kill you with enough amps. That's what makes caps so dangerous. In solid state gear the pack low voltage at huge capacity, while tube gear pack very high voltage at relatively low capacity. Both will make your day pretty bad.