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In theory, yes. We had an array in our lab that we tried to add solid-state drives (SSDs) to, and of course, they weren't the right brand. Vendors have to qualify and test all of these drives, so not every drive will be compatible with every array.
If you have compatible drives for your array, you can definitely add SSDs to an array and see performance benefits.
There are a number of issues that you should consider with the DIY route. This approach may be appealing because shops can use existing technology. However, the lack of automated data migration between SSD and HDD tiers and performance limitations of storage controllers are drawbacks when compared with arrays designed around SSDs.