Questions for a Bridged LM4780 build.

[mcarter14777]

I have been interested in building a LM4780 stereo amp for quite some time now. I am looking to get over 100watts into 8 ohms.

I would like to use 2 of the audiosector boards, each in bridged configuration. I will be completing the build using 2 300VA 22v transformers along with 2 of the power supply boards.

I think I read somewhere that I would need to use these transformers for bridged mode to go from unbalanced to balanced since I don't have a source with balanced output.

EDCOR - WSM Series

but with this i do not know how to make the connections to the amplifier board with the 3 conductors of the balanced connector.

Any help is appreciated!

 

[JonSnell Electronic]

Output from pre amp goes between pins 1 and 4, it doesn't matter which way around. Input ground for both amplifiers on pin 6. Pin 5 to one amp input and pin 8 to the other. Or you could use a dual op amp and one side can invert, if you need more signal drive.

 

[mcarter14777]

Thanks for the reply Jon, but I'm still not sure that I follow.
Peter Daniel posted this schematic that he drew in this thread. http://www.diyaudio.com/forums/audi...-kit-building-instructions-9.html#post1712724

I'm just not sure how the XLR connection goes to the amplifier board depicted in this schematic

 

[mcarter14777]

Actually i think I've got it figured out. It is wired like this? Sorry for the bad ms paint schematic 😀

 

[Peter Daniel]

Yes, that's how it's wired. Only one SG pad should be wired as they are connected internally anyway.

 

[d to the g]

Anyone want to volunteer their experiences with a bridged audiosector 4780?