THRESHOLD S300

I've found s300e's that have balanced inputs but most don't. Anybody know if the XLR was a later addition to the s300e? I notice the used prices jump up for those as well. Or if there are any recommendations in the same price range (either older or newer) that had balanced inputs, any advice would be greatly appreciated!

any THRESHOLD is a present!
 Enjoy.

 Years back, my friend worked for roadrunner records, 
 went in studio, threshold maps and B&t monitors.

 Threshold is superior to most”

Hello, everyone! Im pretty late to the party but I just purchased my first Theshold amp. Iv been wanting one for 30 plus years after first hearing one on a pair of B&W 801s! I bought a S300 bit it does say optical bias on the tag! Anyway Im going playing fore while and then see about doing a recap on it! Its black which i herd is harder to find? Im located in SC i was wandering if anyone could give me a heads up were to take to or send to for a recap?? Im so glad I found this thread.

Thank you!

@onlyanalog,
this has been my first choice for Threshold maintenance:

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