Battery Powered Preamps

IME batteries sound fantasic powering noise-sensitive CDP, transport, DAC, and other line-level SS & op amp devices. Batteries work really well with low-current applications, but are infeasible in all but the most minimalistic of tube designs. However, not all batteries are strong in the area of dynamics & bass control. Large SLA batteries with lots of filtering capacitance perform well in this regard, but are impractical for most manufacturers due to weight and ROHS lead issues. Other battery types are compromised to one degree or another.

I have not heard Dodd, and am not suggesting that a minimalistic design can't sound great. Only that battery power restricts the designer in terms of number of tubes and type of tube used.

BBAM has only several active devices inside(low current op amps) which sound good on stock NiMH batteries, but much better on large SLA, both in terms of supple grainlessness across treble & mid and more dynamic scale and bass authority, owing to lower internal resistance and lower noise of SLA. Generally speaking the larger the SLA, the lower its impedance. In this case size matters in terms of transient response, independent of amp-hour capacity.

With lesser battery setups in my system I've heard a detailed & smooth treble & quiet black background, but pale/soft dynamic contrasts and lack of ultimate slam. If this is characteristic of Dodd, it could likely be improved with additional filtering capacitance and/or larger/faster batteries. Anybody at RMAF, please check out the new Roland battery pre and report as to whether strong or weak on these points. The Roland uses std D cell batteries.

Guido, I don't know if Reference Audio Mods is at the show, but if so, consider stopping by to hear an all battery-powered system that Kyle of RAM & Serge of Audio Consulting in Switzerland have been developing for some time. Like Rowland, they are also doing some impressive things with the latest generation of op amps and batteries.

Pubul57, in low-current source and LS components the new SS monolithic op amps and buffers are particularly good, and if powered correctly may even surpass tubes in terms of transparency & musicality. However, IME op amps don't get to this high level of performance without batteries, whereas tubes can sound great both on AC regulated power or on batteries. The gating factor is finding tube designs that operate within the limited current reserves of batteries.

Another advantage is that monolithic op amps *should* reduce complexity and costs-- though this does not appear to be true of the $18K Rowland pre.

Anyway, my gut is that op amps on batteries aspire to SOTA, whereas(as noted in the 6moons review of RWA Isabella) a tubed pre on batteries is more about high performance in the context of value.

BTW, what I've found is that though an unregulated SLA battery supply can surpass a more complex AC PS, the battery sounds better yet with gobs of capacitance and discrete DC voltage regulation circuits. These features are not inexpensive to implement.