Any experience with Tandberg Amps?

Probably just a bad cap in the power supply, but you could have caused more damage on power up (the Variac takes it up gradually, and you can sometimes "reform" older capacitors). Very likely, your circuit protectors did their job, and there is little to worry. Just bring it to a qualified tech (see if you can find schematics online) and have it checked out. Your probably looking at $150 to $200. You will still be way ahead so don't fret.

I was using it with my polk SDA 1A.........I powered it on and the clipping light blinked and then I saw a spark. It still turns on, but the relay doesn't click on. I always heard people on the polk forum talk about "common ground" amplifiers with SDA's, but they never really said what that means. I took the cover off and I couldn't see any visible signs of damage. What happened?

Also the reason I had to get the fuse in the first place was because I turned the amp on without any speakers hooked up to it, which I guess is a no no.

I was using with my Carver reciever, which I have been using to power the SDA's. The receiver has a pre out and a "main in" with jumpers connected between them. I left the main in section empty and took the pre-out into the Tandberg. There wasn't even any sound, just a big spark.

Before you hook it up and turn it on, you may want to bring it to a qualified tech to power it up on a Variac and check/replace any capacitors that may have dried out over time (they last 10-15 years or so). Just my 2 cents worth. Happy Listening on a great find.

You got a great deal assuming it works.

What speakers and pre-amp will you use it with?

Clean Tandbergs in working order are collectibles. You might even sell it for a profit if desired. They are particularly sought after in their home country of Norway, I have found. I sold my tandberg to a gentleman there a while back.

I had a Tandberg tr-2080 receiver that I used just for the amp section from time to time. It had a very clean, warm and inviting sound, especially for a SS amp. I particularly liked it with my Dynaudio Contour 1.3 mk II speaks.

Not at all bad, I have had a 3026A for close to 20 years and am still using it as a bass amp. Very well built.

It's a pretty good amp, not great. I have seen them in good condition go for well over $500. And depending on how old it is was probably between $1k-1500 new. So to answer your question, the quality is good, as to the sound, that is subjective, you are going to have to check it out.

Regardless, unless it is fried, you've found a bargain.