I have a Dodd battery operated preamp. It sounds very good, but the batteries (four square units well seated in their alloted places) do not play more than about 40 minutes. At that time, the preamp starts beeping to be recharged. It recharges, but then again will not play through a whole CD. Any suggestions?
The Dodd has a switch on the front to select between two sets of batteries, but I understand that this is a holdover from an earlier design and that in fact the preamp automatically uses all the batteries before it asks for a recharge. Changing the switch position to the other set of batteries does not change things. The preamp is plugged in via its adaptor, and is supposed to disconnect the wall power when it is turned on, and then to reconnect to wall power for recharging when turned off. I realize the batteries may be faulty, but it's a new preamp and it seems unlikely. Any guidance is appreciated.
I also have a dodd preamp and phono stage. the batteries in the phono stage were faulty. If I were you I would give Gary a call. He sent me a new set of batteries for phono stage. The origanal batteries in phono stage would only last about 30 to 40 minutes
The batteries are bad. I went throught he same thing when I bought mine last year. Gary has been having some issues with battery suppliers and has gotten some bad ones from time to time. Call Gary, he's very responsive.
The same thing happened to me with a new Dodd preamp. As was mentioned by several others, it was faulty batteries. Call Gary, he's a great guy to deal with and he will ship you some new batteries that are made by a different manufacturer that are very reliable and work great.
my dodds been flawless except when I accidentally left it on too long got the beeps, recharged and good to go
FYI, if you leave it on too long after the beeping starts, it will damage the batteries to the point that they cannot be fully recharged. I have - twice - accidently left mine on overnight. They will recharge, but each succssive use will result in a shorter live until you have to replace the batteries after 4-5 listening sessions. I am much more careful now :)
Also, as an FYI, I have found a battery sold by the franchise store, BatteriesPlus. It's their Werker brand. It's pricey (they will discount if you buy four), but it works very well and it fits into the pre much better than the Powersonic brand Gary last sent to me. Plus they are sold with a one year warranty.
The pre uses 4 batteries an should cost $80 or so. I think the issue with the batteries is if you run them and they don't fully discharge, let's say you operate them 2-3 hours and then you keep'em charging and then play them the next day for 2-3 hours eventually the "memory" of the battery starts working as if a full charge cycle is 2-3 hours so that eventually a full charge is 2-3 hours. I think you need a battery engineer to explain this phenomenon. Managing the batteries properly to ensure 12-15 hours of continuos operation per cycle requires some thought, that can be managed. The preamp sounds incredibly good, so I think it is worth it, but it is not a simple plug and play approach. I wonder if the Red Wine preamp has the same battery cycling issue.
Yes, it's $80 from Gary for a new set (4) of batteries or you can find them from multiple online sources for that price. It cost me $100 to buy a set at my local Batteriesplus store, so it just depends on how desparately you need them. They should last a year or more with normal use. Again, my mistake in killing the batteries was leaving the pre on long AFTER the warning beep went off. My normal listening sessions are less than 5 hours and, in that case, the warning beep never goes off. After a recharge of an hour or so they're ready to go again. I'm confident I could get a least 7-8 hours of continuous use before the batteries need to be recharged under normal conditions. It's really care free, just remember to turn it off when you're done :)
The "memory effect" is not true for the sealed-lead acid batteries (we use SLA batteries, and so does Dodd). In general, SLA batteries want to always be in the fully-charged state, so it is best to turn OFF and charge as soon as you are finished playing (even if you only play for 30 minutes). They don't have memory effect like NiCads.
What is most important is that you never want to deep-cycle SLA batteries, or you can kill them. This is why we designed our SMART module. It continuously monitors the battery voltage and if it falls below the set threshold, it safely shuts off the unit and automatically begins the charge process. So if you forget to shut off, the unit will shut off and charge for you when the battery voltage gets low enough (but not in the "deep cycle" territory).
Regarding the original post, I have to admit that we have also had a few cases of defective batteries that did not last as long as they should have. We are now using a new make/model of SLA battery that is much more reliable and this has solved the issue.
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.
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.
>>"Gary says the batteries lose about 2% of their charge a day without use, and ideally should be played every day."
This is not correct with SLA batteries. Stored at room temperature, the self-discharge rate of SLA batteries is around 3% per month. SLAs degrade from deep cycling and they have a finite number of charge/recharge cycles. The deeper they are discharged, the shorter the overall lifespan of the batteries. This will all be clear when you look at the datasheet of an SLA battery. For example, the Power Sonic 12V, 5Ah SLA datasheet: http://www.power-sonic.com/site/doc/prod/86.pdf
SLA batteries do NOT suffer from "memory effect." However, they DO suffer from being deep-cycled (especially if you do not fully recharge right after use). They ALWAYS like to be in the charged state, so they should be charged as soon as you are finished using them. Even if you play for a few minutes, you should turn off the unit and begin charging. If you are not using the unit for a while, just keep it plugged into the charger and this will "float-charge" the batteries and this will keep the batteries from self-discharging over time. Again, there is NO memory effect with SLAs.
>>"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 cannot speak for the Dodd preamp - I can only speak for RWA products. They feature our Red Wine Audio SMART module (SLA Monitoring and Auto Recharge circuiT)that continuously monitors the battery voltage - and if it falls below 11.5V, we the unit will automatically shut off and being charging. This way, you cannot accidentally deep cycle the unit by leaving it ON and forgetting to turn off. Ealier RWA products (the original Signature 30 and 70s) did not feature this, but the current product range (Sig 30.2, 70.2, Isabella, Isabellina) all feature the SMART module and all our future battery-powered products will feature this. It is an important feature.
The Power Sonic and Enersys SLAs are very good, but we still use a battery analyzer to carefully test and match them for each unit. We learned how important this is because we were hearing from customers whose batteries were not lasting as long as they should. It turns out we were getting some batches of batteries that were inferior (from a different manufacturer) and proved this under load testing and are still trying to get refunded - uggh! So now we make sure they are top-quality before installation.
Vinnie, a local retailer where I bought by last set of batteries suggested that these batteries will suffer reduced life if the batteries are not used and/or recharged while in the upright position, i.e. with terminals on top. I don't recall the exact technical explanation, but they suggested that using or recharging the battery positioned on its side was not optimal due to the way the liquid was contained in the battery. Do have an opinion on this and how do you position the battery in your products?
I'm not sure how the Smart Module works, but it does seem to me that battery powered gear does need built-in "intelligence" to take care of the battery for the customer. I really don't want to think about the battery, I just want to turn on the preamp when I want to listen to music and turn it off when I'm done, and not worry about it. I don't mind replacing the batteries every year or two, but in between, I want to forget all about them. The Smart Module seems to me essential to the design.
This would only be true if the battery was a "wet cell" or "flooded lead acid" type (i.e., most automotive batteries). If you pick up the battery and shake it and can hear liquid sloshing around inside, they you have such a battery.
However, SLA batteries do not fall into this category, as they are AGM (absorbent glass mat) or "gel cell," and they are also valve-regulated , so they do not need to be stored or charged in the upright position. Any position is fine and it makes no difference.