Tube swap question....

[mailmann1971]

Ok, Just got in this Mark III head. guy I bought it from said it was due for a Tube change.
I played it and it sounded awesome. Should I swap the tubes out or keep playing and how will I know when they need changing? Stupid question I know. I been playing for a long time and the only time I have replaced tubes was to get a slight different tone Like from EL-34s to KT-88's.....
I mean I know fresh tubes will sound better but is there a way to know if it needs it or not?
What you guys think?

Dan

 

[dodger916]

Preamp tubes will get noisey (static, swooshing or microphonics). Power tubes will lose volume and definition, and can get noisey too.

 

[stephen sawall]

You do not regardless of what others say want KT88 or any other tubes that are not recommended by MESA in the amp. I have played on a few. None were a improvement at all.

A pair of EL34 and 6L6 was by far my favorite combination in that amp. I run tubes till they have problems or the tone goes very flat and dull. Preamp tubes in most cases well last longer than any of us well live.

For the better part if you ask me .... most of this tube crap is just about people selling tubes making money. I have over $5000 dollars worth of tubes in my collection and some power tubes are good for dozens of years well others are good for less than a year. Just like tires on a car ..... some are better than others.

A lot of new tubes are not very good ..... there is a good chance new tubes well not sound as good as the ones you have. But till you try how would anyone know ?

 

[mailmann1971]

Thats so true. The tubes are Mesa's in it now. Not sure if they are original or what. Maybe the guy that sold it to me just said that to 'CYA" type thing. The amp sounds good but just wasnt sure if there was a way to tell if they are weak or not.
Guess worse case.....get a new set and it they sound the same as what I have in it now.....just set them aside until the old ones take a crap. :lol:

There is a machine or sorts that will let you test the 'strength' of tubes right?
I remember when I was a kid the local drug store had such a machine that you brang tubes in to check them.

 

[stephen sawall]

Those machines a lot of times just let you know if they worked or not .... and not much more.

Eurotubes well test and rate them for a dollar a tube. I have never bothered and he is not far from me. As far as I know he is the only person in the world that is doing this.

 

[mailmann1971]

I am going to get a full set of Power and Preamp tubes for the amp.
Keep the old for spares.
going to keep it the mix thats there now.
Pair of EL34's on the outside and 6L6's in the middle.
I think this is the best combo....
Ordering tomorrow!

 

[Restless Rocks]

Most Power tube sets are sold as matched, meaning they have an almost identical current draw under the same plate voltage and bias parameters. As the power tubes start to age their current draw will start to drift apart from each other and when they are more than 5 ma apart I take that as an indicator for new tubes. Yes great pre tubes can last a very long time but power tubes will eventually reach a point where they are no longer reliable and can short and cause you bigger problems. Whenever I am playing a tube amp I will have a spare set of tubes and even a spare 12AX7 even if the tubes in the amp are brand new.

 

[stephen sawall]

I have seen "matched sets" from some people that were more than 5 ma apart at the start. Some claim 15 ma is close enough. You could not be more right about a power tube going and taking something else with it. I have seen it happen more than once.