5150 Retubing

[Requiemofashes]

So in February I bought an old block letter 5150 (I was in the air with a couple of amps but once I found out that the bulk of my favorite albums, sneap or otherwise got their tone from that I went and snagged it up), now I'm not sure if it was ever retubed or serviced since it's initial. But after having some strange sounds coming from it when I'd turn it on I was told that it's most likely a failing pre or power amp tube so I figured I might as well just retube the entire thing.

So now I'm wondering what recommendations people would have for tubes and also, since I was wondering because I've read that since its a fixed bias amp, I'd be able to just open it up and put in new tubes as long as they're the same type, but then I've also heard the complete opposite so figured I'd find that out too.

 

[Wolfeman]

Throw some 6L6 winged c's in the power section, and whatever you prefer in the pre. You will be good to go.

 

[villeh]

and svetlana c winged ax7 on pre and SOVTEK AX7LPS on phase shifter
that sovtek made a massive chance to my mesa boogie

 

[Requiemofashes]

Alright so today I popped off the back grate and found out I've got Groove Tube 6l6's in the power amp (didn't pull out the chassis to check the preamp ones because I'm a bit paranoid to do that), what type of a difference could I expect switching from the groove to the winged c's? And any other combinations you people recommend?

 

[Notuern]

I cant say what type of difference.. but i'll tell you right now that it doesnt make a huge difference in sound(Even if it is an improvement.).
So what ever you do, dont expect it to sound like a new amp.. it will probably just sound a little bit tighter/articulate then before.

 

[Wolfeman]

Actually, if he has old as hell tubes in there that have drifted bad, a new retube will make a pretty big difference.

 

[Requiemofashes]

I cant say what type of difference.. but i'll tell you right now that it doesnt make a huge difference in sound(Even if it is an improvement.).
So what ever you do, dont expect it to sound like a new amp.. it will probably just sound a little bit tighter/articulate then before.

Yeah I'm not expecting to change the amps overall sound (nor would I want to) I'm just seeing what new tubes with shape what aspects differently.

As for the tubes themselves I'll admit that I don't know how to tell the life on them but after turning on the amp just now when I looked in the back I saw that they were glowing a very dark and dim orange where I could only really see when the lights were off. (so hate being uninformed but if anyone would be so kind as to help explain to me what the deal with tube colors is it'd be appreciated)

 

[Wolfeman]

Yeah I'm not expecting to change the amps overall sound (nor would I want to) I'm just seeing what new tubes with shape what aspects differently.

As for the tubes themselves I'll admit that I don't know how to tell the life on them but after turning on the amp just now when I looked in the back I saw that they were glowing a very dark and dim orange where I could only really see when the lights were off. (so hate being uninformed but if anyone would be so kind as to help explain to me what the deal with tube colors is it'd be appreciated)

Don't get caught up in the look of tubes, some look and glow different than others.

It's always a good idea to retube a used amp as soon as you get, that way you know what kind of life you will get out of them. Do a retube and go from there. Keep the old ones as backups, as they are probably still usable.

 

[Force666]

Not sure if the 5150s differ from the 6505 in this regard, but you don't have to pull out the chassis to get at the preamp tubes. They are located behind a plate on the bottom right side.

 

[villeh]

replacing preamp tubes is super easy and it makes huge difference if old ones are bad. you cant broke your amp

replacing power amps tubes isnt your job, because bias settings
but you can check if they broken:

plug guitar and speaker to amp, switch your amp on, raise some volume (not on guitar) like you were just going to play something. ok, take a pencil and carefully snap every power tube.

if you hear noise from your speaker the tube is quite gone.

99% of sound problems in tube amps are caused by tubes

 

[Force666]

power amp tubes on a 5150 are not adjustable bias. So changing them with a matched quad is fine.

Tapping on any preamp tubes will make a noise. It's only if it's excessive that it has become microphonic.

 

[MetalJonesy]

I started a thread about a week ago on this topic for my 6505 in the equipment section.

Anywhoo, i got some JJs for the power section in mine, they come with JJs stock in the pre section these days and Rubys in the power. They sound awesome, and it is just pull em out and put the new ones in! easy!

 

[GuitarHack]

As mentioned, not a huge difference unless the current tubes are screwed. I have tried JJ, EH, Shuguang, Ruby, Sovtek........ Much of a muchness. Preferred JJ, not any real BIG reason for both Pre and Poweramp. Bigger and tighter bottom than some others is the biggest difference. Although a change of a dial on the amp makes a bigger difference.

"If they aint broke, don't expect such a difference" in my experience. Whatever that may mean.