12 VDC trigger cable

I would like to control On/Off power to my Krell monoblocks using the 12 VDC trigger from my Benchmark DAC2. The Krell has 5 pins midi input/output connectors and Benchmark is using a 3.5 mm female connector. On the Krell side, it looks like I will have to purchase midi cables to interconect the 2 amps. What about the cable between the Benchmark and the Krell? Any idea on cable adaptor? It seems that I would need a 3.5 mm male to midi adaptor but have not found anything on the web.Any clues where I could find these?
I am sure that one of the many cable makers would do a custom piece for a price. There are so many that I hesitate to suggest one, but check with Cullen Circuits for example.
When I went to hookup my KCT preamp to my FPB amp I had to order a special 12v adapter from Krell. It shouldnt be that way but it is. The KCT also has a couple std 12v trigger input/outputs I believe, if that is your pre amp. It has been so long since I saw the adapter I forgot what it looks like. I could not find a picture of it on Google images. I would call Krell and see what they say. Maybe they have one already for this situation.
Good luck, John
Thank you all for the good advice. Krell does sell a 12 VDC trigger cylinder that I have purchased. I just need to purchase 2 Midi cables + male/male mono trigger cable and all done!