Guitar-related terms

Could you please tell me how to pronounce the word Bigsby (it's a kind of tremolo bar used in electric guitar)? Does it rhyme with by? I don't pronounce the diphthong, but I don't know whether I should.

Also, how is the word Gretsch pronounced? (That's a brand of guitars.) Do you pronounce all the consonants? And what's the sound of the vowel like?

Thanks!

Thanks a lot. I see I was pronouncing Bigsby well, and that Gretsch is less of a tongue twister than I thought :-)