Using 2 chips to boost voltage handling

[soundNERD]

If I remember correctly, isn't there some way to hook two chips together to allow double the power supply voltage? What I want to do is power an OPA549 above +/-30 to allow higher voltage output and therefor higher wattage output.

Thanks!
-Mike

 

[loong]

Do you mean the bridge config? If so, you can see the AN-1192 App Note for some detail.

 

[pinkmouse]

Bridging will increase the voltage seen by the speaker, but not allow you to increase the psu rails, so you will still need the same transformer.

 

[richie00boy]

Also bear in mind that bridging causes the load seen by the amp to halve, thus you will be limited to 8 ohm speakers with most chips.

 

[boholm]

If you give your OPA549 more than +/- 30 volts, it will be destroyed.

Bridging is the trick to use: http://sound.westhost.com/bridging.htm

 

[demogorgon]

how about runing one chip on +60v and a nother at -60v, and running them as bridged?

just a quick thought from the top of my head..

 

[richie00boy]

Then you will have a nice 60 volt DC offset going though your voice coil and a nasty smell in the room, if not flames

 

[azira]

how about runing one chip on +60v and a nother at -60v, and running them as bridged?

just a quick thought from the top of my head..

not bridged, parallel... I had an idea like this more than once. Probably need diodes in the output of each amp to prevent them from driving eachother... also would have to deal with crossover distortion.

 

[ErikdeBest]

not bridged, parallel... I had an idea like this more than once. Probably need diodes in the output of each amp to prevent them from driving eachother... also would have to deal with crossover distortion.

As Loong said: you can see the AN-1192 App Note for some detail.

It has been discussed, builded and tested through people from this forum...and...you can find AN-1192 at the website of national, I think it is www.national.com

 

[AudioFreak]

As Loong said: you can see the AN-1192 App Note for some detail.

It has been discussed, builded and tested through people from this forum...and...you can find AN-1192 at the website of national, I think it is www.national.com

AN-1192 isn't going to help much is this situation.

 

[jcx]

yes, repeating a ref to something without stating that it had no new info beyond how to bridge was annoying

but http://www.edn.com/contents/images/45890.pdf might help

"Bootstrapping your op amp yields wide voltage swings" shows how to use transistors to increase V handling

 

[loong]

I don't know exactly what you looking for.

My friend made a brdiged amp using the DRV134 (as the diff driver) to drive 2 op amps (OPA54x) with very compact PCB, it produces very good result. With direct drive by the NAD521i and our taste, it clearly beats the NAD 320BEE.

 

[soundNERD]

i think it was something like this: sorry about the schematic i don't have schematic programs installed on this computer. would this work?

 

[richie00boy]

would this work?

As a voicecoil burner, it would be great. As an amplifier, nope. See my last

 

[azira]

As a voicecoil burner, it would be great. As an amplifier, nope. See my last

I think you are assuming that each chip's quiescent output is centered on it's rails and not at GND.

 

[richie00boy]

Show me a chipamp that can swing right to a rail and I'll give you a dollar

 

[azira]

This kind of what you were thinking soundNERD? I scribbled this down a while ago, still a lot of hurdles to clear before it'd be a usable idea though..

good part is that the chip wouldn't have to swing rail to rail, infact only being able to get within .7V of the rail would be ideal.

edit: I remember now, after posting why I scrapped this idea... diodes still don't isolate the outputs from driving eachother... damn...

 

[leadbelly]

ouch.....

 

[HDTVman]

i think it was something like this: sorry about the schematic i don't have schematic programs installed on this computer. would this work?

Sound heard if this is built.

BANG! Whats that smell?

Source of smell, Speaker, smoke from chip amps, any resistors connected to the circuit, power supply transformer if your not fast or the fuse didn't save you.

This is a bad idea, sorry.

BZ

 

[azira]

This is a bad idea, sorry.

BZ

Can you explain what is bad about it. It's not down on paper will all values listed... but is the idea really faulty? Is this circuit also a bad idea, it seems like sort of the same thing to me.
--
Danny