Hi There,
I am new on this site and found it while searching for persival trumpets. This because this was the brand of my grandfather HJ Kop after whom I was named. On the site I found several trumpets. In several descriptions I saw that there is some doubt. My grandfather is indeed the person behind Persival. He builded the instruments himself in his own factory. 

Kind Regards,
Rik (HJ) Kop

Hi,
I recently saw your question. My grandfather used to have a factory producing all types of horns, handmade. It was a business going on for some time in the family. In fact our last name "Kop" comes from the name of the profession of creating cupper based objects called "Koperslager" in Dutch. My father and uncles worked at that factory, but it was closed 50 years ago.

The instruments go under the name "Persival" but also under his own name H.J. Kop. When I was young he was well known also internationally. Many popular Jazz trumpet musicians attended him when visiting Amsterdam (were the factory was based). Goal of these visits were to experiment with the nozzle. Due to that I have been sitting on the lap of Chet Baker and many more famous jazz trumpet musicians.

That is all I can tell about it. Maybe I can answer more specific questions in case you have any. Let me know.

Kind Regards,
Rik Kop