Help changing tubes in Mark V 25...

[elvis]

I am swapping tubes in my Mark V 25 and they are impossible to get to. I think a previous post mentioned that you would have to pull the chassis. I did that, and it's much easier that way.

Any other suggestions?

 

[gitaryzt1985]

Firstly, what's prompting the change? What tubes are you going with and why? I haven't even thought about this yet. I've heard that Mesa tubes are the least worrisome as far as matching bias go, and that some people even go back to Mesa tubes in the long run. Did you just have one die on you?

I'm not trying to be a Debbie Downer here, just curious as I'm a big tube roller myself.

 

[elvis]

Possible bad tube. Also just practicing for when I need to change a tube.

This is what I have found:

Step 1. Pull V4. Difficult.
Step 2. Put V4 back in. REALLY difficult.
Step 3. Pull V1. Impossible.
Step 4. Try to pull grille. Impossible.
Step 5. Pull chassis. No problem.
Step 6. Pull and replace tubes. No problem.
Step 7. Replace chassis. Oops, need to pull grille first.
Step 8. Pull grille. No problem with chassis out.
Step 9. Replace chassis. No problem.
Step 10. Replace grille. Haven't done this yet.

 

[ryjan]

Step 11.
Modify chassis shell to make grill removable from front with either screws or velcro for easy tube swaps in the future. 8)

That's what I did on my Roadster so I could swap out the preamp tubes without having to take any power tubes out or burning myself.

 

[elvis]

The grille fits very tightly in the space, so it will have to be sanded down a bit so it can be pulled without pulling the chassis. It also screws into a solid front piece that will have to be cut to allow access to the tubes. Pretty well over-built.

 

[ryjan]

It's a bit of a pain but 20-30 minutes with some sandpaper and a little saw now saves a ton of time later.

 

[Dreamtheaterrules]

LOL. I got my Tweaker a few years back and was just loving how small it was and how cool it looked. After lots of tube rolling/testing in my old Classic 30, I remember the first time I decided to roll a few preamp tubes through it. (The Tweaker) :shock:

I really think the V25 will be good enough that I won't do a lot of tube rolling (more playing, less messing around! LOL) but having to remove the chassis to change tubes... well, this amp should be worth it.

Good luck Elvis.

 

[gitaryzt1985]

LOL. I got my Tweaker a few years back and was just loving how small it was and how cool it looked. After lots of tube rolling/testing in my old Classic 30, I remember the first time I decided to roll a few preamp tubes through it. :shock:

I really think the V25 will be good enough that I won't do a lot of tube rolling (more playing, less messing around! LOL) but having to remove the chassis to change tubes... well, this amp should be worth it.

Good luck Elvis.

That's my take FWIW, but I just hope the Mesa EL84s are more reliable that most I've owned, or this could get cumbersome.

Heck, we get a decently priced Mark that weighs under 20 lbs, looks FANTASTIC, and sounds even better and we are STILL complaining about something haha :lol:

 

[elvis]

The power tubes should be easy enough to get to. It's the preamp tubes. Sheesh...

I'm not a big tube-roller, but I will need to replace one once in a while. I think the ryjan method is probably the way to go, though it may not actually be any easier, as you still have to reach into a tiny space, and it's not much more effort to pull the chassis. More dangerous maybe...

 

[psychodave]

Never mind, I figured out the tubes shields are simple twist until it pops up.

 

[MBJunkie]

The power amp tubes are easily accessible.
The preamp tube covers with the MV25 are push and twist (just like all other Mesas I own). Replacement of the preamp tubes on the MV25 pretty much requires the removal of the chassis.
That said, I have had incredible reliability with stock mesa tubes in all of my amps, and have no reason to expect anything different from my MV25. Besides that, it sounds great stock IMO.
My .02

 

[ryjan]

I have an SPAX7 that I bought just for my Mark V:25 when it arrived but whatever is in there sounds so good I can't bring myself to waste time removing the chassis that I could spend playing.

 

[elvis]

I have an SPAX7 that I bought just for my Mark V:25 when it arrived but whatever is in there sounds so good I can't bring myself to waste time removing the chassis that I could spend playing.

Yeah, with stock tubes and gain on 1,000,000, I don't get enough noise to want to change tubes.

Where's your review? Have you recovered from the withdrawal yet?

 

[ryjan]

I have an SPAX7 that I bought just for my Mark V:25 when it arrived but whatever is in there sounds so good I can't bring myself to waste time removing the chassis that I could spend playing.

Yeah, with stock tubes and gain on 1,000,000, I don't get enough noise to want to change tubes.

Where's your review? Have you recovered from the withdrawal yet?

Oh yeah, I'm better now. 8)
I still have no idea how to discuss my opinion of this amp without sounding like a teenage girl with One Direction tickets.

 

[8d2studios]

I am swapping tubes in my Mark V 25 and they are impossible to get to. I think a previous post mentioned that you would have to pull the chassis. I did that, and it's much easier that way.

Any other suggestions?

Why would you hassle that much if its only a matter of 4 screws to get the chassis out? Its so easy to do.

 

[Steve2014]

Possible bad tube. Also just practicing for when I need to change a tube.

This is what I have found:

Step 1. Pull V4. Difficult.
Step 2. Put V4 back in. REALLY difficult.
Step 3. Pull V1. Impossible.
Step 4. Try to pull grille. Impossible.
Step 5. Pull chassis. No problem.
Step 6. Pull and replace tubes. No problem.
Step 7. Replace chassis. Oops, need to pull grille first.
Step 8. Pull grille. No problem with chassis out.
Step 9. Replace chassis. No problem.
Step 10. Replace grille. Haven't done this yet.

Hi,

I was wondering about this, sorry if I am being stupid here (wouldn't be the first time but what is the actual step by step process for pulling the chassis?
Unscrew the four screws on the top of the head? But to me it looks as if the chassis is only kept in place by those four screws is not supported inside the head and is not resting on lip? So as you lose the screws the chassis starts to drop down if not supported?

So is the process:

1) Turn the head upside down.
2) Unscrew the four screws on top of the head while the head is upside down.
3) Slide out the chassis.
4) Remove the four screws holding the grille and remove grille.
5) Slide chassis back in and replace four screws on top of the head while head is still upside down.
6) Replace grille and four screws.

Confirmation of this would great! Or am I totally off track?

Thanks

Steve

 

[2 Boogie]

I took the chassi out when I changed tubes in my amp, this is much easier to get access to the tubes, unless you have very smal and long hands.

2B