Bridged vs Conventional Amps

[destroyer X]

Bridge mode seems to be a problem.

That's what i think about.

And may be the same as you think...because very obvious.

This video was made in Spanish too.... because of people from Mexico and Colombia that have published something that could be bridged.

http://www.youtube.com/watch?v=AajHE45qZ0w

http://www.youtube.com/watch?v=PDgQLOTrAgE

http://www.youtube.com/watch?v=lR6v0msQYzY

first one in English, second in Spanish and third in Portuguese
regards,

Carlos

 

[CBS240]

Hi Carlos

Now if a good phase splitting circuit could be made by simply using 1 transistor, everybody would be doing it and applauding the results. How can you have a low distortion bridge when the two signals vary in phase, especially at higher frequencies? which will happen at the collector in a real transistor as a common emitter. THAT corp has a BAL to SE conversion IC available. While a better discrete circuit is certainly possible, a THAT 1600 I bet would bring them much better results. A signal transformer would be better than a single CE stage for that matter, but who wants to put a piece of iron in the signal path? att'n:unless of course your using those high voltage empty glass thingies
)

 

[Bonsai]

Some of you may have seen amplifiers with specs like this (there are quite a few out there):

100W RMS into 8 Ohms @ 1kHz
200W RMS into 4 Ohms
400W into 2 Ohms
800W into 1 Ohms

Reviewer comments as follows:-

. . . . with power doubling into each halving of the load impedance, its clear the designer thought this amplifer design through, generously oversizing the PSU to ensure the availability of plenty of power, resulting in this amps vice like grip over the speakers, no matter what load is thrown at it. During my listening tests, this wa s confirmed. I have never heard such well articulated and deep bass from my Wilson Puppy's etc . . . .

So, you open the amp and what do you see? maybe a 500VA transformer, 2 x 22mfd and one of those 25A chassis bolt on bridge rectifiers.

How did they do that?

Easy

First, they measure the amp at 1 Ohm load for a few seconds and get 800W

Divide by 8 and get the 8 Ohm rated output.

Of course, when JA then measures the 100W rated amp and finds it actually delivers 160W into 8 Ohms, he says 'a well engineered product, conservatively specified so it should last forever . . . .

So ends marketing BS 101.

 

[AndrewT]

First, they measure the amp at 1 Ohm load for a few seconds and get 800W.............
.................So ends marketing BS 101.

much more likely they used a duty cycle of less than 10% and possibly as low as 1% to take that 800W measurement. This minimises the PSU voltage sag and prevents the transistors and heatsinks becoming dangerously hot.

What they do not have is a 800W into 1ohm amplifier.
If they did measure it for a few seconds starting with an almost cold heatsink, then they do have a real 800W into 1r0 amplifier.