Hey, I bought one of these amps just over a year ago 2nd hand from a local music store for £400, seemed like a deal at the time.

Apart from a tea stain on the front speaker cover, this amp has been perfect up until recently.

Firstly (after the amp has been warmed up on standby ofc) when I turn it on there's a huge crackling noise that lasts for a few seconds before going away, it's a bit worrying lol, after that though the amp works normally.

Secondly the drive funtion on the amp doesn't even work at all, when i activate it there's just a loud buzzing noise and no guitar can be heard.

Thirdly, the knob that controls the volume ontop of the amp seems to be lose and can turn around past 0 which is a bit strange, the volume seems to work normally though.

Apart from those problems the amp seems fine, would anyone know what may be causing the crackling / buzzing problem and how much it'd cost to get one of these fixed?

PS: I'm going to look into replacing the tubes soon while I'm getting it fixed, can anyone recommend the right type of tubes to go for?

Jumping on dat gear sig train.
PRS Hollowbody II / BKP Warpigs
Strandberg OS6T / BKP Aftermath
Strandberg OS7 / Lace Poopsticks
Skervesen Raptor 7FF / BKP Warpigs
Skervesen Raptor 6 NTB / BKP Juggernauts
Hapas Sludge 7 FF / Hapas Leviathan
Anderson Baritom / Motorcity Nuke BKP Sinner Anderson H2+
Warmoth Baritone / BKP Piledriver
Ibanez Rg2120x / BKP Nailbomb

Blackstar ID:Core Beam
You want to put in the same kind of tubes that you had in it before. You can really fluck up your amp by switching types of tubes that you use. If you want to switch types of tubes, then take it to a guitar shop and have it biased for the kind of tubes you are getting.
Epi Elitist LP Plus
Marshall Class 5
Vox AC30 CC2

"A person is a success if they get up in the morning and gets to bed at night and in between does what he wants to do."
You need to take it to a tech

The problem with the rattle when you 1st turn it on probably means your standby switch needs replaced.

The no drive on the drive channel says that something is probably wrong with the overdrive circuit which is a solid stat circuit so simply swapping tubes want fix that either.

The "stop" inside your volume pot that makes it so you cant turn it past 10 is probably broken so that pot should probably be replaced.

These are just guesses based on your description but regardless, it's a good amp and shouldn't be a hard fix so it's worth doing. A retube wouldn't hurt either if you haven't done one for a while.