Did i damage my amp?

[slacker190]

I went to a friends house with my TSL head, plugged into his cab, and the volume was insanely low. Long story short, it turns out his speaker cable has a short between the two wires inside, while still allowing the cab to work (quietly). After returning home, I plugged it into my cab with a good cable, and the volume seems normal, but the amp seems to have slightly less gain and more bass.

Does anyone know what could have happened or what I could test?
Thanks in advance

[Amp Kat]

it turns out his speaker cable has a short between the two wires inside, Does anyone know what could have happened or what I could test?
Thanks in advance

Short or open ? A short won't hurt anything but an open could have caused damage to the OT but you would have known as it wouldn't play at all. I can't think of anything it would have done to change the sound.

[slacker190]

The tip and ring (- and +) of the jack have continuity between them when tested with a multimeter.

[Enzo]

You are measuring the resistance of the output transformer. It is OK.

[slacker190]

After playing the amp today, it turns out one preamp tube was going south on me, which equates to the change in tone. After replacing the preamp tube, the amp is back to normal again.

Thanks for your help.