Soultone is made by Masterworks. Masterworks also produces TRX, HEARTBEAT and Orion (which may now be defunct), and several other Turk boutique cymbals. If Masterworks has any connection, it is with Bosphorus. They both share the same foundry, and though never validated, I would say the same cymbal smiths.
I know this because I was planning on being a Masterwork USA dealer, but decided against it for personal reasons.
Masterworks offers a good product. I have used Bosphorus for years and compared both together finding very few differences.
I would not think of them as a 'smaller Turkish brand'. They are very popular in Europe, as is Aegan Cymbals (very good as well), as well as Russia and Asia. They lack a USA distributor, and were never marketed to the USA/North American as they should be