Battery Powered Preamps

It would be interesting to hear from some designers on the issue, like Ralph Karsten of Atma-sphere and others. Since I know nothing at all about electronics I may be blind to something critical that makes getting on the grid worth the effort. But I do wonder why so much money and expense in preamplfiers center around the power supply, in some lines (e.g. First Sound)the difference in cost, sometimes significant, is almost exclusively centered around the power supply. If the "grid" is such a problem, that needs so much engineering - why not avoid it in the first place -- other than the fact that you have to recharge the batteries evey 6-12 hours (not a problem for me)? Id rather have improved S/N, no power cord issues, no conditioning required. Seems like an elegant solution; and I can attest that the Dodd sounds darn good. I also notice that the BAM on my Merlin Speakers sound better in battery mode than AC mode.

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.

Dgarretson, do you know if the Dodd is a minimalist tube design? It seems to work well on batteries (4 12volt 5 amp SLA batteries - pretty heavy). Not as strong in the bass as the CAT Sl1 but it does seem very balanced. I wonder if Gary Dodd has overcome the inherent problems you describe through good circuit design or not. On my Merlins which only go to 28hz, the bass seems very good and dynamics seem very strong as well (not to the level of the CAT perhaps which is the most dynamic preamp I have heard)but pretty darn good.

In my opinion, you are right on. I'm headed to the Rocky Mountain Audio Festival this week-end specifically to listen to the Red Wine Audio SLA battery components. Aside from the Signature amps, they've just released the Isabella preamp - which includes a battery powered DAC (the other component super sensitive to power current issues).

I've been thinking of getting a Sutherland as my phono stage anyway, so if I like what I hear in the Red Wine components, I'll have a lot of expensive power cords and power conditioning to sell. ;)

Shazam
While in the RWA room, do not pass on the opportunity to listen to Vinnie' new phono stage.
Here are some information forwarded by Vinnie:

- MC / MM input with HI/LOW gain settings
- Adjustable standard load settings, plus a "custom" position for a custom installed load resistor
- Discrete, class-A, zero-feedback gain stage (similar to what we use for the Isabellina dac's output stage), followed by the same tubed output stage as the Isabella (1 pair of 6922/6DJ8s).
- SLA battery operation with SMART module and rapid charger
- Similar enclosure as the Isabella, with sliding glass window on top for easy tube rolling.

I do believe that
*lowering the floor noise
*eliminating any associated problems with power lines
*having the key components of the grid (phono,preamp,dac or cdp)
- are all important, beneficial and ....IMO and experience, sound excellent.

RWA Isabella with DAC is great.
Without trying to sound like a salesperson let me just say that Dodd as well as Isabella/Isabellina dac are one of the easiest recommendations. In fact, I am not aware of a single soul who regrat buying any of the above mentioned preamps.
My next purchase is ......you guessed it - RWA phono (however, I'm not counting out Dodd's phono yet).
I should have it in my home by the end of the year as a part of another shoot out. This time it is all about analog.

Three modified turntables (DIY Red Devil, MMF7 in bamboo double plinth and Lenco l75 replinthed and tweaked)two to three amps (Consonance modified Cyber 800, Melody 300b monos or I2A3 integrated, possibly Manley Stingray integrated, two single driver speakers based on Fostex drivers, carts, arms and phonos line-up will be announced before the actual event.

Should be fan.

Mariusz

While I'm not an engineer, i believe you can call the Dodd a minimalist tube design in that it only employees two 6922 variety tubes and, in fact, only one of the twin triodes in each tube is employed at a time. In other words, you could burn the tubes for say 10,000 hours and then swap their positions and go another 10,000 hours. Certainly, this is a cool benefit given the cost of NOS tubes. (Please don't ask me how this works, I'm just referencing what I've read in reviews :).