Burning Amp BA-3b (Balanced)

[tinitus]

I don't understand why new BA-3 driver/gain amp and BA-2 power amp module can't use individual seperate supply, unlike the F5

I thought the driver/gain amp was more like a seperate preamp
and that you could use any other preamp, like say a tube pre
and the BA-2 is more like a power buffer, with its own bias curcuit

so, I ask again, any reason not to use individual seperate power supply ?
only connection really needed is common signal, yes?

[buzzforb]

Originally Posted by tinitus

I don't understand why new BA-3 driver/gain amp and BA-2 power amp module can't use individual seperate supply, unlike the F5

I thought the driver/gain amp was more like a seperate preamp
and that you could use any other preamp, like say a tube pre
and the BA-2 is more like a power buffer, with its own bias curcuit

so, I ask again, any reason not to use individual seperate power supply ?
only connection really needed is common signal, yes?

It can. You could also have the FE in a seperate case with a connections that allow it to both pass a signal to and recieve power from the main output stage along with its PSU. I have strongly considered this simply because it allows for multiple FE choices without having PSU's for each one.

[generg]

I can only confirm what buzzforb says...

it is possible...

I used two PSU from Aleph P and lowered the combination of Zeners to give 24V

one for the negative one for the positive rail, common grounding, voila!

[Backbones]

Well I've built the single ended version but for future reference if I were to put in another set of power boards for balanced operation I would still only need the one bias board wouldn't I?
Chris

[buzzforb]

Nope. You need a bias board per output board. This would give you four of each + you would need 2 FE boards.

[generg]

I suppose

- when you make the board of one channel longer adding a second board To have more pairs you need no supplementary bias board.....

- but adding a new unit with a separate input I suppose also like buzz that you need a separate bias board

[rsdio]

Originally Posted by tinitus

anyone know of a good balanced digital/chip controller/attennuator ?

You should take a long look at THAT Corporation. They have an ex-military fab that allows semi-discrete topology within their chips. It's practically the equivalent of discrete transistors. They also have extensive balanced performance that exceeds transformer performance.

Probably the most interesting for your specific question might be:
THAT 5171 High-Performance Digital Preamplifier Controller IC
THAT 1510,1512 Low-Noise, High Performance Audio Preamplifier IC
THAT 1570 Low-Noise, Differential Audio Preamplifier IC

More basic building blocks:
THAT 1200,1203,1206 "InGenius" High-CMRR Balanced Input Line Receiver ICs
THAT 1240,1243,1246 Balanced Line Receiver ICs
THAT 1280,1283,1286 Dual Balanced Line Receiver ICs
THAT 1250,1253,1256 Low Cost, Balanced Line Receiver ICs
THAT 1290,1293,1296 Low Cost Dual Balanced Line Receiver ICs

THAT 1606,1646 "OutSmarts" Balanced Line Driver ICs


... and, now that I've mentioned their near-discrete capabilities, some folks may be interested in the following, particularly when matched transistors are needed:
THAT100 Quad Low-Noise NPN Transistor Array
THAT120 Quad Low-Noise PNP Transistor Array
THAT140 Quad Low-Noise NPN/PNP Transistor Array
THAT 300 Series Low-Noise Matched Transistor Array ICs

I wouldn't try to claim that their ICs are appropriate for every design, but they represent a very unique option that folks should consider.

[koldby]

rsdio

If you are looking for a balanced integrated amplifier, my candidate would be the THS4131.
This is not an opamp, it sounds extremely good and Papa has swong his magig wand over the design at some point.

Koldby

[rsdio]

Originally Posted by koldby

rsdio

If you are looking for a balanced integrated amplifier, my candidate would be the THS4131.
This is not an opamp, it sounds extremely good and Papa has swong his magig wand over the design at some point.

Thanks for the link. I have that data sheet in my collection, but I'm not actually looking for an integrated amp.

My goal in mentioning THAT was to answer the question posed by tinitus. He may have been joking, but he may have been serious. I saw a design based around the THAT 5171 chip at an AES meeting, and it really seemed like something that people might find interesting. If you want the kind of control that this offers as opposed to manual potentiometers and stepped attenuators, then it might be for you.

Personally, I want to build one of Papa's balanced input amplifiers, but I plan on driving it from my DAC, which has +26 dBa output levels. I assume that I won't even need a preamp at all if I already have +26 dBa capabilities. I can attenuate digitally and not lose too much resolution.

[tinitus]

hmm, I understand connection of balanced BA3, its simple enough

but when someone asked, why not connect to ground, Nelson said, 'do you not want to be able to drive single ended also

implies that source could be either balanced, or optional single ended
would be nice if someone would explain this further