[AndrewH]

I've had the Sensation M901 since it was new. Now that it's been several years, the sealed lead acid batteries in the Dodd battery kit for the M901 aren't holding a charge anymore. Without the charger attached, they only play for a couple seconds before the amp shut down. Also, I might have been hearing more grain in the high frequencies - perhaps from the charger?

So I bought two of these Yuasa brand 7 amp-hour sealed lead acid batteries for $19 each with free shipping ($38 total):
http://www.amazon.com/gp/product/B002MA6FYG/ref=oh_details_o03_s00_i00?ie=UTF8&psc=1

Their specs claim an internal resistance of 25 milliohms, half that of the PowerSonic batteries that came stock with the Dodd kit (50 milliohms). Note they have the same F1 terminals as the Dodd kit so the existing wires/connectors are plug and play. I put the batteries end-to-end with the terminal sides facing each other. Just make sure to connect things in the same order (short cable connecting red terminal to black terminal, longer cable keeping the red/black color of the wire consistent with the terminal).

It may be my imagination, but the sound with the new batteries might have more bass and be a bit smoother. Not sure if it's the lower internal resistance or the freshness of the batteries, or both. But for $38 total plus 5 minutes installation I'm a happy camper! Another bonus is 7 amp-hours of capacity, versus the original PowerSonics with just 5 amp-hours.

If your Dodd battery kit is more than a couple years old and you use your amp regularly, I recommend trying some fresh new Yuasa batteries.

[wsturner]

Thanks for sharing this info!

We will all have to replace our batteries - eventually.

Scott

[bardamu]

Hello, Just did order 2 big batteries and a ctek charger. I hope tomorrow the parcel will be on my doorstep and beforevthe weekend i will have it working. Have to take care that there will not be any short circuit. It could be easy but i want to construct it in such a way that it will work a decade or more.
Using big AH batteries and find the best way to charge it to achieve long life time.
Will post some pics and tell how it is working.
Sincere greetings, Edward

[rollo]

  Two batteries ? Please explain further. One for ? the other ? Thanks.


charles

[bardamu]

Hello,
You need 2 12 volts batteries to get 24 volts. I just did get mail that they have been send so will receive them tomorrow. Will put some photos soon. Greetings, Edward

[Tarzan]

Hello,
You need 2 12 volts batteries to get 24 volts. I just did get mail that they have been send so will receive them tomorrow. Will put some photos soon. Greetings, Edward

Good work Edward,looking forward to the pictures.

[bardamu]

Hello Tarzan and the others,
The batteries did arrive and are mounted on an aluminium plate. One + and the - from the other batterie have been connected by a copper bar. Now i need to unstall an amphenal style connector next to the connectors on the batteries and take care of 2 cables for charging. Then raise the level of my oppo so thye batteries can be placed right under the oppo next to the sensation. The rack is stainless steel dont wanna short circuit the batteries while sliding them onto the level that is mounted under the oppo level.
Next week will make a front plate with a stainless steel handle. Maybe have a nice digital meter on the front to indicate the charge?
Probably will have it working this weekend.
Sincere greetings, Edward

[bardamu]

Hello,
Just did connect the batteries to the sensation. The original power switch on the sensation was removed when i did need a bigger hole for 24 volts strsin relief. BUT my  choke input power supply had a power switch. So now i dont have a power switch so it was a bit trickybto connect the big power plug.
Maybe will put a power switch on the ctek charger. I will have to see if i can just leave it connected and just switch off the chsrger during serious listening. Right now the charger indicates the battery is ready for use but it isnt fully charged yet.
Would it be necesarry to install a switch between the battery and the sensation because the original power switch st the back has been removed?
Past midnight here so cannot play music. But will do that tomorrow.
Sincere





greetings,Edward

[bardamu]

Hello,
The battery is fully charged. Now a led on the charger shows it is in float mode ( maintaining the voltage at maximum level by providing a constant voltage charge) or pulse mode( maintaining the capacity at 95-100% by monitoring the voltage and giving a pulse when necessary)
For serious listening it would better to switch off the charger. There is no low grade switch to get toasted on my virtue anymore. In standby mode there is only 300 ma current drawing so then the charger will have an easy life. So far when using the choke input i never use the stand by mode.
Now the keep the batteries healthy i wanna give it a try. They are high grade, with 30% discharge they will have more than 1600 times to be able to get charged. If you lower the discharge rate it will be even more. As you can see my batteries are BIG. Some might say to big. I did buy the biggest pair that would fit right next to my sensation. If the sensation would have been bigger then the batteries would have been on the floor where there is more space. I would have gone even bigger. The ones i bought where the equivalent of 150 $ each for 50$ more i would have got allmost double the capacity. If i ever go virtue with my other set up i might do that.
The French who did start using batteries decades ago once did say if you want to have a detailed sound you did a massive power supply. They did compare it to
a scale. If you wanna check the weight of the average american fast food consumer you can use the cheapest scale money can buy but if you wanna weigh an insect you need a very very heavy scale. Of course i did modify the comparison a bit but the idea is the same.
Crazy using this big? Waiting years for a new virtue baby to arrive can be called crazy too.
Sincere greetings, Edward

[virtue]

Wow, that's cool. 

If the battery has an off-switch, you're good.  The switch on the back is right inline with the power input.

Let me know how it sounds!

Seth

[bardamu]

Hello Seth,
There is no switch at the output of the batteries. When i did switch of my choke input i did use the stand by button on the virtue and after that the swictch on my power supply. When connect the batteries i just did connect the big plug you see on the photo. There is no switch to get toasted maybe some copper tracks on the print will get more or less defibrillated. Maybe just solder the wires from the cable that pops inside the amp directly to the big panasonic cap?????
The charger is connected to the mains by just using the power plug. There is no on off switch. Maybe i will put one. There is little connector at the end of the output cable that will let you switch from a short 30cm cable with big connectors( the ones used for cars) to small ones. Would be easy to have a switch there as well. Maybe cables could function as an aerial?
Normally the big connector that is used now will be only be disconnected when doing things like changing input or caps( still did not use the russian caps LOL)
The sound?  Well it sounds great. In my tv video set up it is used for frequencies above 80 hertz( see my other posts).
The first thing i noticed it sounds more at ease. Voices sound very articulate. ( i had to do loads of phonetic writing when studying French language) I even notice this watching British materchef cooking show. Less need to glimpse at the english subtitles for the impaired hearing.
The sound stage did grow larger. Don't have to sit down right between the speakers to have a nice '' view '' When somebody sings it more feels like someone is there. If you are familiar with the looks of the artist sometimes images pop up in your brain. ( no it is 10 in the morning did not smoke pot i never do)
One of my favorite '' test blue ray for my set up is the incredibles (from pixar studios) Even though the virtue starts at 80 hertz the ability to impress with big loads of energy did improve a lot. Normally the protection led would blink a few times and i would have the idea that the sound is about to desintegrate . Of course my new power supply can supply peaks of 400A during 5 seconds. The led only blinks for one second max. There is just no reason anymore for the sensation to kind of fall apart.
Right now the charger is still connected so after installing the switch it might be even better. Maybe because the big AH rating at the quality of the charger the differences could be more subtle than when using low grade chargers.
Yes the Russian caps both teflon and paper in oil are in stock are waiting too.
Sincere greetings, edward

[virtue]

So cool, Edward!

Now please put those things by a window or something.  I don't want you to die in your sleep due to a batter leak of some kind.  Those things look awesome but scary to me

Very best,

Seth

[bardamu]

Hello seth,
These batteries are sealed so you really have to abuse them to make something evaporate. Using a very low grade battery charger combined with the cheapest batteries money can buy could get you into trounle. At work i did see a battery go down but thwt was one which was severely abused.
Never put a battery in an airtight container or in a woodenbox.
Still enjoying my batteries.
Sincere greetings, Edward

[virtue]

Thank you for helping me understand, Edward!

[vonpod]

Hey!  My Dodd battery pack (for same Sensation M901) seems to not be holding a charge.  When I unplug the Soneil charger from power source, the amp clicks off and lights on front of amp go dim.  I purchased these units together from a great Virtue owner in Berkley but I don't know how long he owned them prior to my purchase.  Does this mean I need new batteries?  They're at least two years old if not longer.  I'm not a tech whiz... will I be able to find batteries that fit in the Dodd black metal box and hook up just the same?  Thanks for you help.  John

[vonpod]

Thanks Andrew.  Talked to Seth at Virtue and I think I'm picking up the batteries you listed the link for. I'll let you know what happens.