[Ken Maltby]

Like most devices that use SD cards, the JBL works fine with most SD cards, but you
can find some makes and models that the device will have issues with. Under that rare
situation, a re-format of the card is usually all that is required for it to work.

The JBL reads ebook files off the SD card directly, in fact that is where I keep almost all
my ebook library. I copied the supplied files and folders of the JBL's internal memory into
a folder on my PC, and keep very little in the internal memory (a "Books" folder and a
"Pictures" folder are required in the root of the internal memory, but they can be empty,
and mine are almost so.)

The JBL will throw up a "Too Big" error message for some files, but that has more to do
with the construction of some components of the file than its actual size overall. You
should be able to produce .pdf files that present no problems to the JBL.

As to large documents; I use HTML as my format of choice for large manuals, but only if
a conversion to .epub using Calibre results in a file that the JBL has problems with.

I have a 23MB Manual on my JBL, so size is not likely to be the problem all by itself.

I would start with a 4GB SDHC for your JBL and see how much room that gives you.
You can find 4GB class 6 SD cards on sale at <$10.

Luck;
Ken