should I buy this tube amp?


There is a Unison research simply 845 for sale at a crazy good price, but it has been in storage for the last 2 years. It was hardly used after purchase and has been in temperature controlled storage since. The amp works but there is a distinct hum from the transformer and crackling/ popping sound from one of the channels. Switching the tubes from left to right will change the crackling sound to the other side as well. I assume changing out the tubes will take care of the problem. Other  Questions: 

Does prolonged storage (2-4 years) cause any kind of damage to capacitors? Perhaps cause them to dry out? 
Can any other components be affected by prolonged storage? 
what other important information do I need to ask about a tube amp prior to purchase? 
ei001h
By all accounts I’m aware of this is said to be a very good sounding 845 amplifier. Natural tonal richness, transparent and open sonic presentation. If you have a speaker that will do its 24 watts justice I’d give it a try. Seems to be a well implemented and constructed SET integrated amplifier from a respected Italian manufacturer. 
Charles
I would think for a crazy good price, it would be worth purchasing new tubes and incidental repairs....
Is it possible to have seller test the tubes? If it's near my house, Plainfield, NJ, I'll test them for you.
I always examine the negative to achieve the positive, i.e. think what could go or be wrong first???

do you know any more history, how old those tubes might be? old enough, enough hours played to be problematic? tubes last a LLLLLOOOOOONNNNGGGG time.

very likely transformer hummed before it was put in storage. Perhaps too heavy to ship for repair, no original boxes to ship in, they are from Italy, who might fix them? Remain beautiful after local fix?

Personally, I wouldn’t mess with them, but, if you love them, if you can buy and spend some money for all new tubes, get lucky, or spend more money fixing ___?

Has anyone ever personally heard them, or another integrated Amp from that company?
Amazing sounding guarda they have us repair


Dave and troy audiontellet nj ucunisondealers
The crackling is just tubes. If the transformer itself is physically humming that is probably DC offset and will go away with a clean power source (no DC offset). Dry room temp storage not only does no damage, its the on/off temperature cycles that cause the most wear so storage is better than daily use as far as that goes. 

I buy to get good sound, never to get a good deal. So you just have to ask enough questions to decide if it will be worth living with even if the hum remains.