How To Replace Tubes in a Mesa Boogie Amplifier and Do They Sound Better?

Today we look at how to replace all 12 tubes in a Mesa Boogie Dual Rectifier Roadster amplifier.
Also there is an A/B audio comparison of the old and new tubes.
Intro 00:00:00
Thanks! 00:00:07
Amp Backstory 00:00:31
The process 00:01:43
Replacing the tubes 00:02:35
Old vs new tubes 00:09:02
My thoughts 00:11:26
DISCLAIMER:
Be careful replacing tubes, they can be hot if the amp was just on, there is also high voltage in the amp circuitry.

[@PaulDumasy-bz6hr]

Thanks for sharing. I’ve learned a lot🙏

[@BrianJensen]

Very useful, thanks for sharing!

[@MusicAndWood]

Thanks for the watch and comment! Glad it was helpful !

[@Levelity]

The sleeving on the tube helps with preventing microphonic tubes.

[@laurentduca4788]

Great, thank you !

[@MusicAndWood]

Very welcome, glad it helped!

[@damiankacprzak6211]

HI, are you using your 4 x 12 cabinet with 4 Jensen Vintage Ceramic C12K speakers ??

[@MusicAndWood]

Hello thanks for the watch and comment ! Yes I am! It is very very heavy but, sounds totally awesome! All of my bigger 100+ watt heads really get the speakers moving.

[@damiankacprzak6211]

@@MusicAndWood consider making a full video about this cab after you get to that sweet spot of broken in speakers. There are no videos of a mesa (roadster) into a 4x12 (or even a 2x12) with C12K speakers.

[@daviegarden2624]

Hi, just seen this video. My roadster combo has started to sound quieter and broken up then eventually dies and kicks in again after maybe 15 / 20 seconds. The tubes that are in it are around 3/4 years old, do you think replacing ‘all’ of them, preamp tubes and power tubes might solve the problem ? TIA 👍

[@MusicAndWood]

Hello, it is sure worth a try. If it happens on all channels make sure the effects loop and reverb are disabled and switch to the diode rectifier instead of the tube rectifier circuit with the switch in the back on some channel. If it cleans up enable reverb, then enable effects loop to test them. If I recall both of those also use a tube preamp. If it is one channel only likely just that preamp tube has an issue. If it is all channels and switching to diode rectifier did not clear it up it is likely the power tubes. There could be other issue as well. The last suggestion is to only use Mesa Boogie tubes. I would suggest against using other manufacturers tubes in there, they may work but to be safe I suggest against other tubes. You can always try re tubing but there may be just one or two bad power tubes or something. You can get a tube tester to test all the tubes isolated. If you can't find a bad tube I would suggest to take it to a tech as it will need deeper diagnosis. If one power tube is bad make sure to replace the pair with a matched set. Good luck!

[@daviegarden2624]

@@MusicAndWood Thanks for the quick advice, I’ll follow your suggestions, I have two new Mesa power tubes I’ll use if I have to, thanks again. 👍👍👍

[@SweeetJohnny]

Had the same experience unfortunately on the gig. After my Roadster kicks again after half of the song, sound was decayed and after some 30 seconds died. Fuse was blown and I have to switch to backup amp. Tomorrow after inspection one power tube was gone (white colored). I dismantled amp section (I have combo 1x12) and found 3.75 Ohms resistor totally desoldered flying around 😢 Heat of the burned tube was high to that level that resistor felt down from the PCB. That is when I realized that Mesa really fu***d up engineering process with this combos. In Roadster heads your tubes are up and PCBs down but at combos tubes are upside down, heating PCBs all the time. Tube sockets are soldered to PCBs so heat transfer is huge and soldering on PCBs are horrible (I decided to resolder lot of things). Finally, (that) one 6L6 power tube was gone as well as one rectifier tube 5U4GB. I need to get some tubes now but here in Croatia (Europe) that is little complicated.

[@TheAnalyticalObservers]

Do I replace them in pairs? How are they laid out?

[@MusicAndWood]

I would always suggest to replace the power tubes using matched pairs. Pages 36 and 37 of the manual show the paired layout. mesa-boogie.imgix.net/media/User%20Manuals/Roadster_130613.pdf

[@SweeetJohnny]

Power tubes are matched: 2 outer and 2 inner (or first and forth; second and third from any side)

[@SweeetJohnny]

Preamp tubes no need to be mached but power tubes have. You can buy two pairs of tubes, same or different color (on the 01:22 of above video you can see that he bought two pairs of different colors: RED and GRN). That doesn't matter if you use same color tubes (one pair) on positions 1 and 4 and other pair (color) on positions 2 and 3.