1.75*4 is way less than 8.75, so yes you could stack them, however 2-3in of space above the amp is recommended for proper air flow, so you would be pushing it in that re:. i dont know enough about that stand to say anything about it. just make sure it can support all that weight, and if you "add" shelves make sure that they are solid and secure to the rest of the structure.

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