Pretty sure that balanced topology is not required with a current mode phono pre; the Nibiru, and I believe other current mode phono preamps in existence before the Aqvox were all single ended. I believe the Aqvox was the first to combine both.There are now others, including the BMC and MR Labs Vera.
My understanding is that you are not really dealing with load with these phono preamps; essentially the preamp is designed with a very low internal impedance current driven input (I believe both the Aqvox and the BMC are around 2-3 ohms-others may be different) which essentially acts as a short circuit to the cartridge and eliminates or greatly reduces noise and ringing that might be associated with a typical voltage input and loading options.
The BMC is essentially a turbo charged Aqvox built to higher standards and designed by the same guy, who now runs BMC. The BMC may well be better but I still like the Aqvox's ability for fully variable gain adjustment within its range. I think Candeias should have implemented that into the BMC.
Below are links to Fremer's reviews on both the BMC and the MR Labs, which might give you a bit more technical insight into the designs; most of it goes right over my head ;)
http://https//www.stereophile.com/content/bmc-phono-mcci-phono-preamplifier
http://https//www.analogplanet.com/content/current-affair-intriguing-mr-labs-vera-20-mc-phono-preamplifier
My understanding is that you are not really dealing with load with these phono preamps; essentially the preamp is designed with a very low internal impedance current driven input (I believe both the Aqvox and the BMC are around 2-3 ohms-others may be different) which essentially acts as a short circuit to the cartridge and eliminates or greatly reduces noise and ringing that might be associated with a typical voltage input and loading options.
The BMC is essentially a turbo charged Aqvox built to higher standards and designed by the same guy, who now runs BMC. The BMC may well be better but I still like the Aqvox's ability for fully variable gain adjustment within its range. I think Candeias should have implemented that into the BMC.
Below are links to Fremer's reviews on both the BMC and the MR Labs, which might give you a bit more technical insight into the designs; most of it goes right over my head ;)
http://https//www.stereophile.com/content/bmc-phono-mcci-phono-preamplifier
http://https//www.analogplanet.com/content/current-affair-intriguing-mr-labs-vera-20-mc-phono-preamplifier