Organ, St Brelade's Church, Jersey, c.1910 - Postcard
https://www.ebid.net/uk/for-sale/organ-st-brelade-s-church-jersey-c-1910-postcard-231504306.htm
Being a computer person, I tend to favour a wide definition of what counts as a computer, remembering that the narrow definition is what usually comes of (perhaps unknowingly) adding the constraints 'general-purpose', 'personal', and 'digital'.
But an analogue synthesizer is a tricky one. One can argue that there are mathematical principles underlying the operation of the circuitry. But the hard part is arguing that it is 'computing' something.
There are inputs, and there is output. But it does feel like it opens the door to every church pipe organ being a computer. (-:
Organ, St Brelade's Church, Jersey, c.1910 - Postcard
https://www.ebid.net/uk/for-sale/organ-st-brelade-s-church-jersey-c-1910-postcard-231504306.htm