Ok some normal hifi speak for a change, I never been a big fan of balanced as 90% of the time to make them balanced a lot of the equipment manufacturers just bundle in more opamps into the single path to make it balanced input or output, very few are true balanced and discrete all the way through, you need to see the circuit diagram to find this out. Even the advantage of it does nothing for me, it's just so I'd be able to run 20mt interconnects with good noise figures. In the end most hi end poweramps speaker outputs are + and ground, single ended again.
I have tried doing balanced Lightspeeds quite a few times and even when double quad ldr's are matched perfectly they go out of calibration after just a few hours sometimes days because they are exponentially more critical to temp drift. And it is exponentially harder to match double mathed quads for balanced as it is single matched quads for single ended.
It can be done with sensors that would measure a test tone before each listening session and then do an auto calibrate circuit, but that then takes them away from being a matched set with the same i/o impedances for each channel, they would get wildly different readings and therefore each channel will sound slightly different to the other at different levels. Or you could do a feedback type arrangement then your asking for more crap in the signal path and making them active and creating distortions /colourations.
After one and a half year of developing Wapo seams to have hit a brick wall with his on diy, http://www.diyaudio.com/forums/analog-line-level/170381-precision-led-ldr-based-attenuator-15.html#post2687081
what I presented to them is the way it is, with development going back to 1974 in all sorts of formats, but they love to tinker, and good on them, this is how man reached the moon, but it's sad to see them as he said "This project has hit what appears to be an insurmountable brick wall."
Cheers George
I have tried doing balanced Lightspeeds quite a few times and even when double quad ldr's are matched perfectly they go out of calibration after just a few hours sometimes days because they are exponentially more critical to temp drift. And it is exponentially harder to match double mathed quads for balanced as it is single matched quads for single ended.
It can be done with sensors that would measure a test tone before each listening session and then do an auto calibrate circuit, but that then takes them away from being a matched set with the same i/o impedances for each channel, they would get wildly different readings and therefore each channel will sound slightly different to the other at different levels. Or you could do a feedback type arrangement then your asking for more crap in the signal path and making them active and creating distortions /colourations.
After one and a half year of developing Wapo seams to have hit a brick wall with his on diy, http://www.diyaudio.com/forums/analog-line-level/170381-precision-led-ldr-based-attenuator-15.html#post2687081
what I presented to them is the way it is, with development going back to 1974 in all sorts of formats, but they love to tinker, and good on them, this is how man reached the moon, but it's sad to see them as he said "This project has hit what appears to be an insurmountable brick wall."
Cheers George
