Power supply question, TDA2030, 2050 Chip amplifiers.

[brett]

Quick, maybe easy question:
How 'good/regulated' and below specified voltage do power supplies have to be for these very versatile chip amps?

Real life example I'm facing:
I bought a TDA2050 module. It has an on-board 470uF filter cap for the supply.  The TDA spec sheet says it is a 50V max device with max output of 50W (1A draw).
My supply is one of those "black box" regulated supplies (like laptop supplies).  It puts out 55V with no load and also 55V with a 0.5A load (27W). It's rated at 2A (110W).

My questions:
1. Will the 55V supply kill the 50V TDA2050?
2. Will the noise be OK or horrendous?
3.  Should I use a simple Zener regulator to establish 48V at 1.2 Amps?  1.5A?
4.  Should I go the 'whole hog' and stack 2 x 7824 regulator modules? (They each have 2x 470uF filter caps.  But they are only rated for 1A, so no wriggle room wrt current).  Photo is each module.  Is this complete overkill?

Thanks for suggestions

[PRR]

2) Have you figured how big a resistor and Zener have to be to handle a varying demand up to 50 Watts? (More, because a 50W linear amp pulls 70 Watts of DC at nominal audio power.)

1) ALL the TDA2050 on market today are re-marked something else, something lesser (maybe 2020), or just bad copies (even the rejects are gone). Small manufacturers around the world have scoured the market. Fahey in Argentina has resorted to making his own discrete modules to maintain his amps in service.

The universal DELL 19V supplies may be safe. It seems the fakers can make a chip good enough to pass incoming inspection at modest voltage, but go flooey past 25V or 30V.

[antonis]

Should I go the 'whole hog' and stack 2 x 7824 regulator modules? (They each have 2x 470uF filter caps.  But they are only rated for 1A, so no wriggle room wrt current).  Photo is each module.  Is this complete overkill?

I shouldn't trust that SMD bridge rectifier for nothing more than 500mA or so..
(in full knowledge of the facts..)

[MrStab]

There are plenty of Gainclones in the world with no regulation at all on the power amp rails, only giant caps. Like the 68W one in my living room, which sounds awesome and isn't noisy! Use an IC with a higher max supply voltage rating and only regulate the pre-amp, if anything.

[brett]

Thanks for the quick replies:
1. Thanks PRR for the reminder to make a 70+ W supply for a 50W amp (50W music power, so probably only 40W continuous).  Concerning a simple Zener regulator, I was shooting for 4 ohms (4 x 1 ohm 5W resistors). Simple, brutish, and should work OK to step down about 7V at 1.5 Amps.  Given they'll be in a hot corner somewhere, I think it's prudent to have 20W of ratings for a little over 10W of V x A.
2. MrStab.  Thanks for the reminder just how many good amps rely on big caps and little else.  The 2050 has soe voltage gain and a heap of current gain, so I need to be a bit careful.
3. Antonis.  Apologies for the misleading photo.  I'll ditch the bridge, as I'm using a 55V DC supply.  Although the voltage drop might be useful to me, the two conducting diodes in the bridge will fry well below the required current. 

Thanks everyone.  I've learned and enjoyed. 
[And I've realised that I have a TDA2050 chip running on a similar-looking "48V" supply.  It was for cheap and cheery line level amplification, so I only put a filter cap at the DC socket.  I've never run it at high volume, so don't know if it's noisey.  And I don't know if that TDA2050 has been surviving higher than its 50V maximum supply voltage.  I'll DMM it tomorrow.

Thanks again