Profile A1200 XL Odd Power Supply

[amc32]

I came across this amp needing repair.Nothing special! Until I looked closer. Power supply fets blown.It appeared to have dual operating swithing power supplies. But when I began removing the blown fets,I realized each supply had 7 fets per transformer. What the hell gives?
And 7 fets appear to operate the other transformer. Long-Story short,once removed from chassis,the transformers are acutually in parellel with each other.I would think that this design would cause more problems than it would solve.What's the point? What's the benefit?What a waste of space.

This is the first time I've seen this design operating as such.
Any input for the sake of knowledge would be nice.


P.S. Amp was repairable, just wounldnt trust or want it in my car.

[ppia600]

I don't remember much about the layout but I do remember being impressed at the shear capability of the internals. My friend had one that melted the terminals loose and I had to tighten them and resolder. The amp was very powerful and actually had enough transistors to warrant the long heatsink. It actually looked like an domestic amp on the inside, and the board was red.

[amc32]

I remember that version also.It seems somewhere when Profile was making a name for themselves,they swithced topology.The early A300,A600,had red boards and were made in Korea with the A1200 being two A600 strapped together.The later Profile has green boards,plenty of gaps,and made in China.With the A1200 having a single PWM power supply,with two PWM transformers in parrellel with each other.

Still wondering whats the benefit of this design vs (true)Dual PWM?
Still wonering how many licks it takes to get to the center of a Tootsie Roll brand lollypop. Hmm the world will never know!

[ppia600]

White version, type I had to repair:

http://ampguts.realmofexcursion.com/...lifornia_1200/

the later blue model:

http://ampguts.realmofexcursion.com/...fornia_1200SX/

[theAnonymous1]

Vaguely reminds me of the BOSS PD-400 I have. It has 16 power supply fets, dual transformers with their outputs paralleled, and 20 output transistors.

http://ampguts.realmofexcursion.com/Boss_PD-4000/

[amc32]

The Boss is a nice import amp decent power too. Boss board is the same as Lanzar VHC2000.

16 Fets Total in PWM, Four banks of 4 Fets,Each pair of banks work together switching off and on. Half Bank turning on other half turning off. Output voltage and current from transformers summ together rectifiers. Works great.


Notice the symetry. 16fets 4banks 2transformers


Profile: 14fets total, 2banks (7each), 2 transformers (All transformer taps in parrelle with matching taps of other transformer.
One full-wave retifier for DC voltage and current



will post pics soon....