Originally Posted by highfigh
I think some people are equating 'Class D' with SMPS, "All Digital", etc. I had a Sony integrated amp with PWM power supply, driving a Class AB amplifier and it's still out there and working very well, AFAIK
. I had to replace the power supply's thermal fuse, but that's because I was using it to drive a pair of horn-loaded Peavey PA woofers for a band, with the amp bridged into 4 Ohms, fed by a Crown active crossover with normal and inverted outputs. I decided to bypass that part and put a fan on it for the rest of the gig and the only other problem it had was when I asked our service tech to check its output and specs on the distortion analyzer in the service department. It launched a diode in the bridge, so he replaced all four with something that he said "will handle about eight of these amplifiers". NEVER had another problem and it output at rated distortion (.01% THD and IM, 20Hz-20KHz, both channels driven) was 186W/ch, even though it was rated at 100W/ch.
'Digital' means different things, to different people. Look at power amps used for live sound- many are now using SMPS and they usually live long, work great and sound great. They're not necessarily expensive, they put out a ton of power and audiophiles hate them but the fact is, they sound as good as much of the others that are available. The primary reason they went away from using heavy transformers? It costs more to transport heavy amplifiers.
Today at 2:07 PM
You would be correct in saying people confuse Class D, along with it's power supply.
You are also correct in saying the freight cost is ONE of the reasons the industry wants to move
to SMPS. This is but one reason only. The whole market model cost is lower. They can build the entire
power supply for one tenth the cost, of the COST, for an OEM manufacturer to produce an OEM toroidal
transformer for you.
Actual amplifier costs to produce use to be about 10 percent of the final selling price, according to Randy
Slone, the retired electrical engineer who passed away, with the toriodal costing about 33 percent of the cost, and Old school amplifier boards with heat sinking the other 33 percent. Eliminating this stuff reduces the entire cost of the amplifier by 66 percent. So just putting in an SMPS supply is a huge savings, 33 percent, , and changing over to class D, another huge savings, 33 percent, of same margin.
They have essentially accomplished turning water into wine so to speak as far as profitability is concerned.
There is always someone with a single story about how their single Smps amplifier has done so well for them and is still working. For every single story, there are thousands of stories of failures, and this is for newly produced SMPS amplifiers that they have had over 20 years to perfect by now.
The Pro audio industry actually sells off their entire SMPS inventory on a 3 to six year schedule, because failure is not an option in their business. and it is cheaper to replace everything new for them, rather than deal with maintenance costs. Even the Pro audio industry that buys these amplifiers, is smart enough to know when to unload them.
As far as performance is concerned they do a fairly good job at 20 to 20000K performance. They still are lacking in the 30hz and under, or bass portion.
SMPS is not digital. It is simply a system that pushes the incoming line frequency to such high levels that only a small power up transformer is required, if any at all. Digital means different things to different people, because they do not understand what is, and what is not digital.