Cigar box style Quicksand

[Karl5150]

As I admitted in the Gallery post I can't claim I'm the first to think of using an 18V power tool battery, but it does work well. 
There were two main things to consider: cutting the top plate (1/4" Alder) and mounting the battery receiver securely, they have a pretty positive engagement.
I lucked out with the dead Ryobi sander that was the donor. It has stiffeners along the sides and, unlike the flashlight or drill, the battery mount is attached front and rear. Once amputated from the rest, the receiver had a total of 5 screws holding the two halves together (overkill).
I realized on the first attempt that cutting a perfect, or even an acceptable hole of such an odd shape in the top plate was beyond me. I cut a second with a smaller hole and using the stiffeners as guides employed a Dremel to notch a small step around the receiver. This allowed for a reasonably flush mount without visible gaps.
To fasten the receiver I first wanted to just hold it in place, so a bead of silicone around the underside seamed the call. By the time I had trimmed back the applicator tip of an open tube far enough to extract the plug of dried silicone I could have just as well trowelled it on.
Once my sea of silicone had dried I removed 2 of the screws (1 front, 1 rear) from the receiver and carefully drilled through holes. I slid an old worn drill bit (Reuse, Recycle, Redesign) through each and propped them up with wood supports glued to the underside of the top plate. Very sturdy, pretty ugly.
Were I to do it again, while fitting the receiver to the top plate would probably remain the same (but I would use WAY less silicone) I think I would make the whole thing smaller (I bet a 5 x 8 would work).   
Karl

[4krow]

 Now, this is exactly what I like. I didn't get it at first, then it all came together. I applaud the use of items that still have life in one way or another. To that extent, I even used an old exercise machine (parts of it) to make an outfeed sort of table for my table saw. Works like a champ, and even looks like it was made for the part. You have done the very same thing here, and to me, that is a feat in and of itself.

[Karl5150]

After reading the reply here and on the Gallery post and looking at my other 18V tools I realized that a dead one is a rarity and that each one would be unique if it were the one that had suffered the untimely demise.
My set of 6 inexpensive 18Vs are close to 15 years old and the sander was abused on projects better suited to a corded model.
The trick would be using just the battery. The batteries are heavy enough, and this is not a portable amp so the weight would hold it in place. Looking at Black & Decker and DeWalt models battery terminals it seems like either a suitable fixed or snap on ring type connector with flexible stranded primary wire would work.
I ran the amp for about 5 hours Saturday on an unknown charge level driving a pair of DIY bookshelf 2 ways (6.5" (sub)woofers and heavily padded Fostex FE126s) at a reasonable level in my condo 26 x 12 living/dining room.
With a full charge used it 2 hours at home on Sunday and the amp is at work now driving some inefficient padded NHTs backed up by even less efficient passive 8" subs crossed at about 150Hz.
1 o'clock on the volume is fine for office listening.
I'll post a follow-up on battery life later.

[4krow]

Hmmmm, now where did I put that old 14.4 volt batt?

[WK3K]

Wow, been away from the forums too long - LOVE this idea!

[4krow]

 As time goes on, I consider powering as much equipment by battery as possible. Of course, there are more situations that just wouldn't be practical.

[Grainger49]

My Ack! dAck! is battery powered.  I consider that one of the secrets of how good it sounds.  The BHDAC is getting a battery powered upgrade kit.  I'm betting it is well worth the price of admission.  But the price has not been announced yet.

[4krow]

Grainger,

  That would be a good candidate for battery power, since it will better isolated from causing any noise on down the line, and so many power supplies these days are the switching type. If Edison had his way, things might different. Like we would have a power station on every block supplying DC!

[Karl5150]

As promised (threatened?) impressions on sound, battery life, etc.
First, this little amp sounds great. I have been using just the SuperZeros and I am very happy, there is enough bass for casual listening in the near-field. Most of the time I listen to Sirius streaming through the old, converted car receiver. As expected the sound really benefits from a better, higher gain source. Fed by my NuForce DAC it all comes together very well.
I am using the small lithium battery from Ryobi and getting about 30 to 35 hours on a charge. As always YMMV. If I wasn't so entrenched in Sirius (or at least streamed it from the web where I could enjoy a higher gain signal) and invested in some more efficient speakers I bet I could just bring in a freshly charged battery on Mondays.

[Karl5150]

After enjoying my Quicksand at work since mid May, it developed a problem yesterday. I first noticed a little scratchiness under the music in the left channel then a while later the left side went quiet. Swapped cables, still the left channel out of the amp was silent. Swapped batteries, no help
I took it home and touched up all the solder joints from the board out to both input and output. 
It worked fine at home for about 1/2 hour and for about 3 hours back here at work this morning, then the same symptoms and result.
Time to remove the board and heat up those joints?
Thanks for any suggestions.

[Paul Birkeland]

Time to remove the board and heat up those joints?
Thanks for any suggestions.

Change the batteries.

[Karl5150]

Paul, thanks for the quick reply.
With the batteries (18V tool batteries, 1 fresh off the charger) I'm using, I get 18+V at the board with the amp on.
Previously when the battery dropped below 9V I would get a clicking sound in both channels, experienced at least 3 times while trying to ascertain battery life.
Again, this problem has been isolated to the left channel.
After sitting unplugged for over an hour both channels are playing fine now with no unwanted noise or imbalance.