Battery Powered Preamps

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 :).

I don't know enough to fully understand Dgarretson's technical explanation, nor whether Gary Dodd might answer "yes, generally true, but...." I do know the Dodd seems to be a pretty effective implementation of battery power and a whole lot simpler than complex power regulation and power supply I've seen in some of the preamps I've owned before. Since there haven't been many battery powered preamps before, I suspect that either battery technology has improved, or new thinking has found a way to deal with some of the issues Dgarretson raised. If that is the case, it would seem battery power holds a lot of promise compared with our traditonal way of designing preamps.

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.