The Future of Audio Amplification

dear  guidocorona,

the truth is hard. But is needed to change something what is limited.

Electrolytic caps aren't famous for having exceptionally low ESR, but they're the only technology that's compact enough to provide the current capacity required. The sub-optimal ESR leads to internal heating of the capacitor. The heat dries them out, the ESR rises, that causes them to make more heat, they begin leaking electrically, and they eventually just short out and start frying silicon.

David Bernnig used a switching supply in his TF-10 preamp which was made in the early 1980s IIRC. I have a customer in town with one of those and it has the original filter caps in place- very much alive after all these years. He seems to have sorted it out- those filter caps run cold to the touch. The first statement in the above quote is false- electrolytics are the only technology that's compact enough to provide the **storage** capacity required, not current. 


SMPSs don't need a lot of capacity because the switching frequency is so much higher. This means that a much smaller capacitor can be employed than in a 60Hz supply. I know some SMPSs did have some problems in the early part of the 2000s, mostly on account of some Chinese caps that were failing not because of switching frequency so much as the parts were just plain defective.

There's a huge difference between a pre-amp and a power amp. SMPS's fail all the time in applications that require real current. Laptop chargers, battery chargers, TV's, you name it. These things failing isn't a rare occurrence. It's an everyday thing. There are businesses out there that do nothing but repair SMPS's for all kinds of machinery, and it's generally the caps that go to hell. 

There’s a huge difference between a pre-amp and a power amp.

Correct, two different active Class-D subs and one SR reciever I’ve had on my HT system, have eventually blown their smp caps, and in a chain reaction taken out the class-d amp as well, luckily new plate amps were available, and at trade price, just cost effective to repair for myself only, no way for a customer, they would maybe have been better of as Ricev’s said junking it and buying a new one.

Cheers George

I too hav3 class D A great small company in Denmark Pascal Audiomake excellen5 digital modules. I bought the Danish 
Gato Audio 400-S  then they build their own analog input output sections ,and International rectifier developed a super high speed switcch8ng for their 2 high power Mosfets my integrated sounds 
like a very sweet  SS- Tube combination . Of course I upgraded 
the fuses ,and put a very good Oyaide Sunami Power cord 
and in processs of matching the wiring throughout.
VH Audio has a Excellent Wire Thea Cotton centercore are multi Litz Small Wire awg21 solid core Upocc solid core Copper and thin porous Teflon which is the closestdielectric to air. Incredible wire, I did the whole Xover and cables ,speaker cables , now Amplifier power supply, and Loudspeaker terminals ,also
to all replace any Brass to at least high purity phosphor Brinze 
or gold over Copper RCA Connectors,IEC input ,and Speaker connectors .
Over 70 % of companies use Gold over Brass rca, IEC, and speaker terminals, Not Good but true.i sold audio for many years.. Itis a amazing upgrade  the conductivity is 3-4x  better ,which is a fact . just lookup metals resistance ,conductivity,and great wire 
throughout creates a fantastic synergy, I also use premium Xover parts  and bypsss caps, and the Zobel networks I make for the back of a Loudspeakers is simple but effective ,and cost effective.
if you or a friend is handy these are things to Strongly consider doing. You raise your systems potential at least 15% minimum is not more.