Interesting mix-up.

[jaslan]

I have a Mark V head and separate speaker cabinet with a Cab Clone. I have had good success recording into Cubase with this setup but decided I wanted to do some "silent" recording and monitor via the audio interface so I unplugged the speaker cable from the back of the Cab Clone labeled "thru to speaker". Now, no signal was getting to the audio interface at all. I scratched my head for a minute and thought, "could I have the speaker cables in the back of the Cab Clone backwards?" For example, the speaker connected to the amp input on the back of the Clone and the amp output connected to the live speaker output/through jack of the Clone. I had been getting sound before unplugging anything. I traced the cables and, sure enough, I had them backwards. I guess those two jacks could be a common terminal where the Clone can draw the signal from and it doesn't really matter which jack the amp output and speaker are connected to. What do you think? (Just curious...)

Anyway, here is really my point in posting...
So I have been using my amp this way for at least several weeks since the last time I moved anything. Obviously, I was getting (normal) sound out of the speaker and the Clone was connected so the amp had a load, right? It seems simple to me but I admit I had a nagging concern with what I have read about what playing the amp without a proper load connected can do to it. Besides, I haven't noticed any difference at all with the amp or the Cab Clone as everything seems perfect.

So, the real question is, could I have done some damage that I haven't realized yet?

 

[Jeronimo]

I also made a mistake with connecting the cab clone, and and had the amp without a load for a short period. I wanted to play through headphones but I did not hear anything so I increased the volume till I realized I messed up and did not connect one of the cables...

Apparently Mesa build quality allows for user errors! On other amps you will damage your output transformer or other components.

Anyway, my amp still sounds the same so I think nobdamage was done

 

[jaslan]

I tried that too. I increased the volume trying to hear a signal then plugged headphones into the Clone before I realized my mistake. That was a relatively short time (1-2 min) but I am more concerned about the period of several weeks (at least) with the Clone hooked up wrong.

 

[Jeronimo]

As long as you had the speaker connected so you had a load you should be ok.

 

[bandit2013]

If your amp is dead with load required, the obvious answer is yes. If you plug the amp into the thru out jack, you are turning off the internal load. Not a good idea. Manual indicates the thru out jack is a switch type and will disconnect internal load resistor when a 1/4 plug is inserted. If you have a speaker connected on the other input may be okay but if you want to go silent, not a good practice.

What could happen in the event of no load (such as unplugging the speaker when playing though the amp) will generate high voltage transients that potentially will damage the high side components. Tube or screen resistors may fail, or something else may get damaged. The accidental turn on and finding out there is no speaker connected may not cause any major damage but the potential is there.