advice needed, best sound in a small space?

I'm designing a board to fit a small case, roughlt the size of my touch and 19mm thick. Of the dozens of amp circuits out there I have settled on one that i hope will give the best performance, it is basically a 3 channell active ground opamp(voltage gain) to a buffer(current gain), with the buffer being all descrete components.

I'm trying to minimize board space so that a large enough battery (14.8v lipo) can be used to get at least 10 hours, possibly 20+ of use.

So far i can get everything to fit, at least on paper, but it is proving to be quite a challenge, both trying to use quality aluminum caps (vishay or nichicon) and large metal foil resistors, and keeping a good ground plane around all the traces and pads.

Two things i have been considering:

First, using some 0805 sized resistors would make things a lot easier, there is enough room to stack them, basically making a larger wattage resistor out of 2 0805's in parrellel. as I have read that the larger (wattage) the resistor the better. So, outside of the $15 bulk metal film resistors, is there a good 0805 substitute for the large through hole metal film resistors used in most desktop amps? If not, I have found some Vishay metal film resistors in a MELF that are not much larger than a 1206, would these be a good candidate?

Second, there are no caps in the signal path, just a large cap ro the main V+/- power rails, and two smaller caps for the opamp V+/-, And I know no body seems to like tant caps due to the possibillity of shorting, but outside of that would there be a down side? The caps I am interested in are  the MUSE F95 http://nichicon-us.com/english/products/pdf/e-muse_f95.pdf , they are listed as "audio", and would be a huge benifit as far as board area is concerned, has anyone ever tried them?

The more SMD i can use, the better i can lay everything out to get good ground plane isolation of every component, so if there are suitable SMD components, that wont hamper the performance, the better.

The other option is th go with all the big stuff that are tried and true, but use a much smaller battery and live with ~4-6 hours of play time. personally i would take a hit in SQ ( provided it was a very small hit....) to get a more usable amp.

Any help and advice is greatly apriciated!

Joe

Thanks,

As for the battery, Yes, I know about the charging and discharging considerations. I have 4 500ma (tenergy) batteries on order, along with a small PCB to handle the charging and discharging.  Tenergy also offers slightly larger 900mah batteries that i wold prefer to use, but i need to verify he actual size.

Still wondering what type of resistor wold be best, metal film? tant film?, I will have 3 or 6 boards, so its possible I could make a few versions to see which one sounds best.

As far as signal path length, on this design has very, very short trace lengths. Still have a fair amount of layout work to do, but so far its looing promising.

I wil have to see what kind of DC ofset it wil have, it is similar topology to a mini3, and the few of those I have built didn't have much if and DC offset.

Joe

Thanks, I have read a few places that an oversised (wattage) resistor tends to "sound" better, I am not sure that could be verified, ut if i had to find a reason that it would be that way, i would guess that the closer an amp pushed a resistor to its max rating, the more pronounced the resistors audio "faults" would become. This is purely conjecture, i have no idea if it has merit or not, but i do see a lot of the higher end amps using much larger resistors than the circuit would need. Unless I use some very expensive resistors, it would be very easy to stack a couple of SMD resistors to up the wattage, and still have a small footprint, so i figure why not?

Those panasonics do look very good on paper, and the 0805 size is perfect. I will have to order up a bunch. thanks.

Joe