Smoke on my power amp


I was listening the music with the right speaker wire detached to listen to the left speaker alone. The speaker wire was still attached at the amp side. My preamp does not have the balance knob.
After 20 secs or so, there was a smoke on my power amp.
I quickly turn off the amp.
Once smoke comes, would it be safe to turn it on again? I wonder whether it is permanently damaged.
Is it not safe to listen to the music with the speaker wire detached from one speaker but still attached on the amp side?
My amp is Plinius SA 102.
Any comment?
thx


128x128ihcho
I think what itsjustme said wasexactly what had happened. Feel so dumb.
 I am in Michigan, two hour north of Detroit. About a year ago I had it serviced in Chicago, drove five hours.
I may try there again, or I might it send to Galbo Design. 
It would be $300 both way of shipping and maybe at least $500 for service? I wonder whether it is worth while to fix it. Used price of this amp is around $1500.
Thanks for all your replies.
why....why.....why.....would you even do this is beyond me.

for someone that has been in this hobby for a while, you should know better

now you have to pay to ship the amp both ways ( or drive ) and get it serviced.

you just had this thread recently.....

https://forum.audiogon.com/discussions/should-the-power-be-off-every-time-changing-cables


All I know is that the vast majority of amps I own or have owned have a huge warning in the owner's manual that states not to operate the amp without speakers being hooked up. And I think you now know why. It is NOT safe to operate so don't even think about it...
Most amplifiers have a protection circuit that should prevent damage when the speaker wires are shorted. My Vincent and McIntosh amps both shut off immediately when that happens...Don't ask me how I know....   
Well, I feel so stupid about what I had done.
Anyway, I was trying different preamps, different IC cables, different speaker cables, and different sources (CD/SACD players and phono cartridges). While I was playing around, I got a bit sloppy.
I would still like to have the amp with a built in protection mechanism to prevent such case. It is so harmful to the power amp, but having no built in protection mechanism for $5K amp a decade ago does not sound right.
I cannot find any clear damage from these two inside photos. Any of you see burnt components or circuits? Thanks much.
https://photos.google.com/photo/AF1QipPSt_CM_-03crVgXYW6NBwEgfAXc3eNWuPSAlBJ
https://photos.google.com/photo/AF1QipNIz2uuUz90t-qmUl15mIkIjsxDoqVbj8YsuPLa