Dodd preamp battery plays 40 minutes

I have spoken with Gary of Dodd Audio, and he adds to what some of you have helpfully posted here. According to Gary, he now realizes the trouble is not with faulty batteries (though he has replaced many for customers) but with the way such batteries work and the way they are often used.

Gary says the batteries lose about 2% of their charge a day without use, and ideally should be played every day. This is partly because of the "memory" of such batteries, about which there seems to be some disagreement. Gary thinks they do have it, and that it is therefore important to use them regularly for near their maximum play time. If you only play them 2-3 hours a day, especially when new (if I understood this correctly), then they will be able to play only something like that time span, so Gary, but actually they can play 10-12 hours at a time if they're used that way to begin with. If you'r away or can't play the preamp for an extended period, it's better to keep it plugged in, so Gary, but it will degrade the life of the battery.

While the manual that came with the preamp says that one should ideally not play the preamp till the beeping starts, Gary says it's better to play it till the batteries are nearly empty, even till the beeping starts, so long as you then turn it off/charge the batteries. The preamp can play another two hours or so after the beeping starts without damaging the batteries, per Gary.

Vinnie, I take it some of this has not been your experience? Also, what brand of battery do you find works better? Gary recommended Powersonic, but said others work fine too.

Finally, Gary said he can sell you (me) new batteries, but it's better for the user (me) to go out and get them locally, because to get a decent price he needs to order several cases of the batteries--and then they sit around and degrade to the tune of 2% a day.

Vinnie is certainly right about SLA batteries. To extend useful life, a 12V SLA needs to be topped off with charge as much as possible, and discharge below 10.5V (even for deep cycle models) will permanently weaken them. It has nothing to do with memory effects. One way to avoid problems is to install a cheap signal-powered digital panel voltmeter across the terminals to keep a close eye on them during operation and charge cycle. Lasker makes a nice $25 model. Enersys probably makes the best SLAs in a wide range of sizes, but no SLA will survive repeated deep discharge.

I have not heard the RWA, but owned the Dodd. There is no question that the Dodd is a great sounding preamp. But there seems to be a need for some way to relieve the user of the battery maintenace issue. It should not require that much thought to use your preamp. I'm not sure if Vinnie's preamp works differently.

I am getting 3.5 hrs. of playing time on my 6 month old batteries.

I run it till it beeps.

A real PITA.

BTW, Ibex makes an inexpensive industrial-quality 1.5A 12V frame charger with a battery protection circuit that disconnects the battery from the load in the event that voltage falls below 10.5V. I would consider this type of feature mandatory for use with low amp-hour batteries like the Dodd. Another approach would be to buy a larger battery and cable to it externally-- which would give you a whole weekend of use. The low-impedance large SLA batteries also sound better.