The KT 120s are the power tubes. The 6SN7s, 12AU7s and 12AX7s are small signal dual triode preamp tubes, even though the 6SN7s look quite a bit different from the 12XX7 tubes. There are differences between the 12XX7 tubes even though they look the same. Don’t change tube type without checking with the manufacturer first. They’re not interchangeable. Sometimes there are variants (say of a 12AU7) that can be substituted.
Millercarbon likes to make pronouncements from on high rather than relate his experience as just that, his experience. He thinks that what works for him is the only correct thing for anyone else to do. Don’t let him throw you.
I’ve never heard your amp so I can’t really advise you on what to do next, but I can say that changing all the tubes could make a serious difference in the sound you’re getting, if you get the right tubes. You may also get the sound you want from only changing some of the tubes. Listen to your amp for a while to allow it to burn in and for you to decide what changes in the sound you would like to hear, although it sounds like you’ve already done some of that.
The place to start would be the manufacturer or his US distributor. Manufacturers generally use current production preamp tubes because they can’t get enough quality vintage tubes to fill their needs. Vintage tubes usually cost a lot more too. Everyone uses new production power tubes. There are different power tubes to try, though. Most people involved with tube gear try vintage preamp tubes in their amps, though, and are willing to share what they’ve learned with their customers. So if other Line Magnetic owners don’t chime in, give the US distributor a call.
There are a number of tube sellers who may be able to advise you. I’ll list a few, just google the names. They'll talk to you for free. Don't buy a bunch of tubes till you've got at least a couple opinions.
Vintage Tube Services
Jim McShane
Brent Jessee
Upscale Audio
Good luck, enjoy!
Millercarbon likes to make pronouncements from on high rather than relate his experience as just that, his experience. He thinks that what works for him is the only correct thing for anyone else to do. Don’t let him throw you.
I’ve never heard your amp so I can’t really advise you on what to do next, but I can say that changing all the tubes could make a serious difference in the sound you’re getting, if you get the right tubes. You may also get the sound you want from only changing some of the tubes. Listen to your amp for a while to allow it to burn in and for you to decide what changes in the sound you would like to hear, although it sounds like you’ve already done some of that.
The place to start would be the manufacturer or his US distributor. Manufacturers generally use current production preamp tubes because they can’t get enough quality vintage tubes to fill their needs. Vintage tubes usually cost a lot more too. Everyone uses new production power tubes. There are different power tubes to try, though. Most people involved with tube gear try vintage preamp tubes in their amps, though, and are willing to share what they’ve learned with their customers. So if other Line Magnetic owners don’t chime in, give the US distributor a call.
There are a number of tube sellers who may be able to advise you. I’ll list a few, just google the names. They'll talk to you for free. Don't buy a bunch of tubes till you've got at least a couple opinions.
Vintage Tube Services
Jim McShane
Brent Jessee
Upscale Audio
Good luck, enjoy!