Stereo sub out to mono, is it safe?

Well, before tha manufacturer could get back to me the amp arrived and had a problem right out of the box so it is going back to the distributor. I will keep all of this info for the future and hopefully it will help the next person who is wondering. Thanks everyone

I had the same issue.I just got a new Music Hall a70.2 integrated amp and Martin Logan Vista speakers.My MH integrated has pre outs that the manual says can be use to hook up a sub.I had a old paradigm sub that only has one line level input.So I used a y adapter to combine both Right Left into the sub.It worked but made my main speakers mono.So I just use the right preout into the sub.This sounds decent but not perfect.I am waiting on a new HSU sub with right left inputs to do it right.So for me using the y adapter made my new integrated mono.

Thanks, Loomis. I've answered in your other thread.

Best regards,
-- Al