I couldn't get much out of this trumpet at all.
Recently I got custom Stork mpc after lots of help from Phyllis Stork.
It worked well with my B flat, which is all I had used it with until today.
I stuck it into this 'c' trumpet this afternoon, and wow - an instrument that had been a struggle suddenly sprang to life.
I'd been going to sell it and try again, but no more. Dodgy valve? Well, no longer.
I guess I also have an answer to my favourite mpc as well!