Tube Replacement Help

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MCreel

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I've never changed tubes before, but my amp needs em.

So, I'm wondering what you guys suggest I get. I've got a Mesa Nomad 55 single.

Thanks for your thoughts.
 
What's your question...which tubes to get or how to change them?

Also...how do you know your amp needs a tube change?

Keep one thing in mind...Mesa amps have their bias set based on specific power tube tolerances...and they don't have a bias pot for you to adjust for other power tube tolerances.
What that means is...you will be better off buying your power tubes from Mesa for your specific amp.

Many other amps allow the end-user to set the bias as needed for a given power tube...but Mesa does it differently. :rolleyes:
On the preamp tubes...you can try what you like, but maybe you might be better off just buying them all from Mesa...and then follow your manual for changing.
 
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Sorry, I guess the question wasn't as clear as I thought it would read. When I asked what I should get I meant what kind of tubes.

There's a ton of hissing coming from the amp so I asked a friend who knows a lot about these things and he walked me through inspecting them. The back ones are still on, but the front ones are really loose and when you jiggle them it crates a lot of static.

He suggested I just get a whole new set. I knew I could just hop on Mesa's site (and have looked at them already) and get the same ones that are in there, but I didn't know if someone here would give a preference for one kind of tube over another.

BTW - sick studio Miroslav. Maybe someday I'll find myself able to come to your place and do a track.
 
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miroslav said:
On the preamp tubes...you can try what you like, but maybe you might be better off just buying them all from Mesa...and then follow your manual for changing.
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Just to clarify - whatever bias strategy Mesa uses, it doesn't affect the preamp tubes, and balancing is not an issue, either. Experiment.
 
ggunn said:
Just to clarify - whatever bias strategy Mesa uses, it doesn't affect the preamp tubes, and balancing is not an issue, either. Experiment.
Click to expand...

Right.

I just meant that if he's going to get the power tubes from Mesa...he could also get the others too.
They do have a 12AX7 phase inverter in V5(?)...which needs to be balanced.

MCreel said:
I knew I could just hop on Mesa's site (and have looked at them already) and get the same ones that are in there, but I didn't know if someone here would give a preference for one kind of tube over another.

BTW - sick studio Miroslav. Maybe someday I'll find myself able to come to your place and do a track.
Click to expand...

Again...if you want your amp's power tubes to be spot-on...you should get them from Mesa since their amps have bias set according to a specific tolerance. If you get other brands of power tubes...it will be hit-or-miss since you will have no way to adjust the bias to accommodate them if needed.

On the preamp tubes…experiment, just make sure the phase inverter tube is balanced.
 
before you go to the expense of retubing here's something to try... especialy as you commented on being able to jiggle the tubes...power down and let the power supply filters drain... an unpopular way that i see no trouble with is to play a big fat chord and hit the power switch (not the standby) that will get most all the juice down... then you can take a wire and short the rest out... any how the thing you want to do is make sure all the little gripper things inside the socket are getting a good firm hold of all the pins of the tube... i use a dental pick for this but small (jewlers) screw drivers work well... just close up any that look too open...i've seen this solve all kindsa problems in and of itself... bad connections can have a capacitive effect... as to what tubes to get??? preamp tubes experiment all ya want... on a boogie though it realy is easier to get the boogie tubes and be done with it... can you rebias for other tubes... sure.. but it aint alotta fun...
 
Chances are that the tube making the noise is in the preamp section. If you turn your amp on and (using a chopstick or pencil) tap the preamp tubes you may well be able to hear which tube is causing a problem,You don't necessarily have to do the whole set. If you don't keep your amp cranked all the time your tubes can last a long time. I have every reason to believe the tubes in the 1965 amp I usually use are original to the amp.

I've read the Aspen Pittman book. He was in the business of selling his tested tubes. In my experience, unless the PI tube is way out it will be fine.

If you crank your amp alot you should have a spare set anyway.
 
With Mesa, I tend to agree to just stick with Mesa's tubes. Normally I'm an advocate for trying all sorts of brands of tubes but when it comes to Mesa, I usually advise to stick with their branded tubes. They're not bad tubes by any means and at least you know you're getting a consistent setup every time you stick a new tube into the socket.
 
dementedchord said:
an unpopular way that i see no trouble with is to play a big fat chord and hit the power switch (not the standby) that will get most all the juice down...
Click to expand...

It's unpopular because it doesn't actually do anything except let you know audibly when the tubes have run out. I mean, it's not going to hurt anything, but the tubes are going to discharge themselves regardless of whether or not you smack your guitar. After that, just unplug the amp and you should be good to go.

As far as buying from Mesa goes... I mean, I'm no expert, but I'm pretty sure there's nothing that sets the bias in the actual tube, it's only set in the amp, so you should be fine with any set of tubes you buy as long as they're the right kind. A lot of Fender amps are fixed bias, but you don't have to buy tubes from Fender to make them work right...

Having said all that, I agree that a good place to start is by just retensioning the tube sockets. Here's some reading on that to get you started. You may also just want to try cleaning the sockets. You can get some contact cleaner from RadioShack (NOT the lubricating kind) and spray that on the prongs of the tube and just work it in and out of the socket a couple times. When I swapped tubes on my amp, it didn't work at all at first until I retensioned and cleaned the sockets.
 
miroslav said:
Yes.

Here are some comments from Aspen Pitman, founder of Groove Tubes:

Balanced Phase Inverter Tube
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Written by someone who sells balanced phase inverter tubes, innit? I'd say he has a vested interest in promoting the idea that the two sides of a preamp tube can be unbalanced and that it is a bad thing. Can you cite anything from someone impartial?
 
thebigcheese said:
It's unpopular because it doesn't actually do anything except let you know audibly when the tubes have run out. I mean, it's not going to hurt anything, but the tubes are going to discharge themselves regardless of whether or not you smack your guitar. After that, just unplug the amp and you should be good to go.
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not true... if you dont play through it the filters can retain a charge for quite some time...
 
MCreel said:
I've got a Mesa Nomad 55 single.
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Sick amp, I owned and loved a Nomad-45 2x12 for many ears before joining the dark side and grabbing a Recto. I still think that's one of the most versatile amps Mesa has ever made.

Changing tubes is easy. I used to use Eurotubes sets of JJ pre and power tubes in my old Nomad with good luck - if you go from a tube vendor and tell them what kind of amp you're playing, they can generally make sure you get what you need - a duet of 6L6s that draw current about where you want it for a Mesa, a balanced phase inverter, and normal 12AX7s for the rest of the positions.

Changing tubes on a Mesa is easy - turn it off (if it's on), let the tubes cool off, and then simply pull out the old ones and put the new ones in. Mesas are fixed bias, and unless you're digging around in the chassis (which you really shouldn't have to for a tube swap on a fixed bias amp) there's no need to worry about charges.
 
dementedchord said:
not true... if you dont play through it the filters can retain a charge for quite some time...
Click to expand...
When I did some mods to my amp, the instructions that came with it specifically state:
"You can hear the sound fade away if you leave your guitar plugged in. It is not necessary to play; it's just a way to know that the caps are empty."
The tubes discharge themselves through the capacitors, so you playing doesn't really have any impact on that. If anything, I would think it would make them take longer to discharge since you are putting more current into the tubes by playing, but I'm not experienced enough to be able to actually say that.

Either way, having done the mods and not bothered even having a guitar plugged in when I went to discharge the tubes, I can tell you that it is absolutely, completely unnecessary.
 
ggunn said:
Written by someone who sells balanced phase inverter tubes, innit? I'd say he has a vested interest in promoting the idea that the two sides of a preamp tube can be unbalanced and that it is a bad thing. Can you cite anything from someone impartial?
Click to expand...

Well...he's no longer in that business (he sold it to Fender)...but most tube resellers offer balanced and matched tubes...not just Groove Tubes.

True, a phase inverter circuit is not going to be 100% balanced by the nature of it's design...but I guess using a balanced tubes keeps the favorable imbalance limited to the circuit's intended design...and doesn't introduce additional imbalance.
I mean..it doesn't need to be an absolute 100% balanced tube...but without a curve tracer...you have NO idea just how balanced or imbalanced any random tube is going to be.
Buying balanced tubes removes some of the guesswork.
Of course...you can also just try out a bunch of tubes in the PI position and pick the one that makes the amp sound the best. :)
Most guys don't have dozens and dozens of tubes to try out...so for the OP...buying a nice, matched/balanced set would be the sure thing.

I like to try out various tubes and have a few of cases of NOS/used/new tubes of all types, preamp and power tubes, for my amps...along with a high-end tube tester, and bias tools/testers...etc....so I'm never "stuck" with just one set, but I certainly have come across many that just sound crappy, so I mark 'em and toss 'em back in the box.
 
Ruby

Without a doubt I would try a set of Ruby 6L6s. They are my favorite currently produced 6L6 and when I had a Mesa I swapped out the stock tubes for Rubys and there was a substantial difference. Increased frequency range, more impact, and it adds a pleasing sparkle on the top end. Plus, they're pretty reliable.
 
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