how to buy an used tube amp

[Massili]

Hi,
Im considering on buying an 5150/6505 head and got some business going on.
I'm not an expert about tube amps and i'd like to know some tips on how to buy a good condition used amp.
I read something that best way is playing it and see/hear if that is sounding good. Of course, i believe, it's not the only thing to do and i don't know what to do/ask/check to buy a good piece of equipament without giving me headaches later.
So, what do u advice me to ask/check/test with the seller about the amp and keep myself smart enough if he's trying to overreach me instead of being true and sincere?

 

[ahjteam]

play it for 15 mins. If it turns out sounding healthy and the price is right, grab it.

 

[El_Gato]

You can go to a music store with your guitr and ask for the amp to try some hours before meeting the seller if you're not used to the tone.

grab your guit and test the used one if it turns out good as expected.

Or you can borrow one from a friend and go there and compare them at the same time. I did this when I bought my Musicman Bass as I'm not a proper bass player so I verified it was ok.

 

[Loren Littlejohn]

Yeah I say play for at least 15 mins, even if it's with a piece of shit cab (when I bought my 5150 the seller only had a piece of shit marshall mg cab) if it doesn't make any goofy noises you have yourself a good deal.

Also: I wouldn't say this is a deal breaker, but I would go ahead and turn all the knobs a bit and see if they crackle at all. If they do like I said, it's not a deal breaker but maybe you could heckle him .

Also: I would (if you can) bring a pedal and see if the loop is ok.


If you don't play guitar, have the seller play for 15 mins

 

[Massili]

Shouldn't I ask the seller what's the year of the amp? When was the last re-tube, bias adjustments? What are the tubes brand/model currently equipped in the amp?
I thought i should ask that and depending of the answers wouldn't be a good deal.
Is an old amp still realiable?