Depending on how many channels you want to control, a basic 4-channel dimmer pack might be sufficient. My preference is the https://www.amazon.com/Leviton-D4DMX-MD5-Programmable-Integrating-Stand-Alone/dp/B0049MO3QC because it has actual 5-pin DMX jacks, 10 amps per channel, and breakers instead of fuses.

Thanks for your replies. I thought about using these dimmer packs and just use 6 of them as 15 A is plenty for old lights. What are your thoughts? The protocol box is fine but I really can't find a good cheap one. The cheapest I found was around 750 dollars. And for 150 dollars more I'm sure the board won't mind getting brand new dimmers.