350W Power Amp with LM3886'S

[zafira1981]

Is it possible to build a 350W rms (load = 8ohm) with LM3886's?

the AN-1192 have a 200W but that's not enough.

thanks
Jorge

[jaudio]

You might get 300rms bridged parallel with +/-40 volt power supply but you will have to deal with getting rid of the heat. After that lm3886 become output voltage limited. Maybe the TDA7293 or TDA7294.

[Tweeker]

Pushing it, +/- 42V and 6 LM3886s would pretty much get you there.

[jaudio]

Originally posted by Tweeker
Pushing it, +/- 42V and 6 LM3886s would pretty much get you there.

Yep near 360rms but isnt that cutting it very close?

[Tweeker]

Very good heatsinking and steady mains would be required. MWP has run a bridged gainclone long term at this voltage. Or you could regulate, a good idea, but LM3886s just are not the easiest way to get 350 watts @ 8ohm.

Another possibility is more bridging and floating some of the amps above ground

[sagarverma]

Originally posted by Tweeker
Pushing it, +/- 42V and 6 LM3886s would pretty much get you there.

one single spurt in power supply and pufffff goes out smoke from whole setup.+-42v is high

leave lm3886,its powerless when compared to tda7293,great quality and modular application allows u to connect several devices in parallel.so u get a any amount of power u desire.

[Tweeker]

Would 43V zeners and MOVs on the primaries and secondaries save you?

[abid_rehan]

to protect the chips u need to use something like UPC1237HA, and relays, if u read carefully datasheets of these chips many a cases will suggest output protection at 0vRMS input ....

tryshorting ouput with something like 2 V-RMS and wow u ve got couple of blown chips at ur hand.
My recomendation use a protector circuit particularly when u r looking at something like 350 watts RMS

[tlmadsen]

Sorry but you simply can't get 350W RMS in 8 ohms out of a bridged/parallel LM3886 based amplifier.

I have made a bridged/parallel based on LM3886
(see http://www.diyaudio.com/forums/attac...amp=1061370653)

and even with a regulated supply of -/+ 42 V you will not get to 350 W in 8 ohm, despite how many LM3886 you use.

Remember that paralleling LM3886 gives you extra current and you can go as fare as you want by just adding extra chips. (in theory you should be able to get 1000W in 1 ohm with the right supply and cooling, if you need that)

However you also need some voltage across you load and to get extra you can bridge, but it will only give you max 2x the voltage across your load and you can not take it any further.

With a 2 x30 V AC transformer and a bridged/parallel set-up of at least 4 x LM3886 you get 200-250 W RMS in 8 ohm. And trust me, it is a lot !

Have fun

Thomas

[jaudio]

OK so inceasing supply voltage to say +/-37 voltage will not incease output voltage in a parallel bridged amp?