#1
Hey guys, I'm kind of a newbie to tube amps...I've had a Mesa Boogie Triple Rectifier amp for about 5 years. I'm now getting to the point where I am more serious about my playing...so my question deals with the tubes...in the back I have 6 6L6 tubes and 3 5U4GB tubes...all of the 6L6 tubes glow, some brighter than others...and none of the 5U4GB tubes glow at all...

After reading the Mesa manual, I can't figure out what is normal and what is blown or dying...can someone enlighten me on this topic? Especially the 5U4GB tubes...they don't glow at all and I have no idea if they are good or not...I can't crank the volume due to the apartment I am in, so I can't really tell if there's a bad distorted sound. On the rare occasion I due play loud, it sounds fine...there's a little bit of a hum...but even if it sounds good, I still want to know the situation with regards to the tubes...thanks so much for reading this!
#2
Glow is not a reliable indicator of whether a tube is working or not. Some tubes glow more than others. If the rectifier tubes were blown the amp wouldn't work at all.

It's less usual for a good quad of power tubes to glow at different level though so it may be time for new power tubes. There's no good way of determining when a power tube is dying besides the sound in most cases. In some cases a totally dead tube will be cold when the amp is on, but not always and usually you'd notice the amp sounding weird or not working at all if a tube failed that badly.
#3
Where's the "rectifier" switch, diodes or tubes?

These tubes that are not glowing are the ones that are supposed to transform the incoming current from the AC mains from alternate to direct, and I suppose you just have the rectifier switch on diodes, so you have diodes doing that instead of tubes.
Name's Luca.

Quote by OliOsbourne
I don't know anything about this topic, but I just clicked on this thread because of your username :O
Quote by Cajundaddy
Clue: amplifiers amplify so don't turn it on if you need quiet.
Quote by chrismendiola
I guess spambots are now capable of reading minds.
#4
Those are the Rectifier tubes. I haven't used a Mesa, but I bet those tubes aren't used unless the Rectifier switch is set to tubes and not diodes. Just my guess.
Ibanez Prestige RG852MPB
Ibanez Prestige RG652KFX
ESP E-II M-1
LTD AW-7
Schecter Loomis NT
EVH 5150 III 50
PRS 212 DB
Line 6 POD HD500X
Deadhorse OD/Boss HM-2
#5
Nope. The heater is connected regardless of what mode the amp is in. The heater current is what causes the glow.
#6
Quote by Spambot_2
Where's the "rectifier" switch, diodes or tubes?

These tubes that are not glowing are the ones that are supposed to transform the incoming current from the AC mains from alternate to direct, and I suppose you just have the rectifier switch on diodes, so you have diodes doing that instead of tubes.


The switch is set to "Tube", not "Silicone Diode"...if that helps any...so let me see if I understand correctly...the 6 6L6 tubes all glow, but with different intensities...so maybe I should get some newer tubes...and the 3 5U4GB's do not glow at all, but if they were blown then the amp wouldn't work at all...is that correct?

I took it to Guitar Center and the guy just kind of blew it off and was trying to sell me tubes without even plugging it in...
#7
Quote by Roc8995
Glow is not a reliable indicator of whether a tube is working or not. Some tubes glow more than others. If the rectifier tubes were blown the amp wouldn't work at all.

It's less usual for a good quad of power tubes to glow at different level though so it may be time for new power tubes. There's no good way of determining when a power tube is dying besides the sound in most cases. In some cases a totally dead tube will be cold when the amp is on, but not always and usually you'd notice the amp sounding weird or not working at all if a tube failed that badly.


Thanks for the input...any suggestions on power amp tubes that won't break the bank?
#8
You're right, if the rectifier tubes were blown the amp would make no sound when switched to tube rectification.

As for power tubes. Throw some JJ 6L6GC's in it.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#9
For forget, you have more tubes in that amp (called the preamp tubes) they may not be easily visible but they are in there. If you haven't noticed a degradation in sound I wouldn't worry about the preamps so much, just good to know they are there.
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
#11
Its completely normal for the filaments of the rectifier tubes to be dimmer than the 6L6s.

We recommend changing power tubes every 1.5 - 2 years of normal use. Keep in mind of you aren't using MESA tubes, you need to use a power tubes that is rated correctly for the fixed bias setting found in MESA amps - this is a mid-current draw rating (such as 4-6 on the Groove Tubes scale) Thanks!