Burning Amp BA-3b (Balanced)

[Zen Mod]

no;

I wrote that to myself , as reminder and continuo of one great friendship , between me and myself

[buzzforb]

Smart ***! Meet you for drinks in the Pub.

[generg]

With the values show in the attachement you have

balanced in and balanced out a gain of 4x

balanced in and unbalanced out a gain of 2x

for people that do not need much gain.....

the values are 150R for R22

and 470R for R23/R24

and I think the distortion might be even lower in simulation....
but I can connect the THD meter only to one output, so there is no cancelation of distortion....

[permaneder]

Here are small knapsack circuits for the BA-3 boards from the diyaudio shop. They allow to switch from one channel balanced mode into stereo unbalanced. They are simply soldered into the holes for the two 100R resistors that lead from the wipers of the 100R pots to ground.

OFF-ON-OFF = balanced, the two 100R resistors are in line, ON-OFF-ON =unbalanced, the two resistors are laid to ground.

[permaneder]

...and here is the complete BA-3 board

[buzzforb]

Nice work. Your power fets are on the way.

[mns80]

I am thinking about, ok almost decided already, to build the balanced version of the burning amp with the BA-2 output stage.
However I am still unsure if my calculations are ok or not regarding voltage/current/devices and dissipation figures.
Can someone have a look at the picture with the numbers I've come up with and say if they are fine or completely rubbish? To clarify beforehand the amount of Fets are counted for ~20W per device.

[wintermute]

Ok so I have read this thread twice now. I get that if you want to go this route that as well as doubling up the FE you also need to double up the output boards.

SO is it as simple as one output board is the speaker out and the other is the speaker return? with out+ from the FE going to D the speaker out output board, and out- going to D on the speaker return output board?

What about the power supplies? separate or shared for the two output boards?

I think I'm going to wimp out more than likely and just build a standard BA3, as I don't have anything with balanced outputs, but the lower distortion and higher power didn't escape my attention (and I'm imagining that even with a single ended input, those advantages don't go away??)

Tony.

[buzzforb]

Go balanced.

[wintermute]

Buzz this comment from generg worried me. I don't know exactly how to interpret number2. As I will only have unbalanced inputs for the forseeable future that comment worries me

Also I still don't know for certain what I have to do to make it balanced!! apart from buy BIG heatsinks

Tony.

Originally Posted by generg

what I can say to the qualities of BBA-3.......

I have a Meridian CD-Player with balanced and unbalanced output....

with BBA-3 the difference between balanced in and unbalanced in is very very big......!

Such a big difference was not to hear with Aleph P and even Pumpkin(g) my favorite pre...

conclusion....... 1. the balanced input of BBA-3 is the best I ever had.

2. the unbalanced input of BBA-3 is the worst I ever
had...