#1
Okay I have had my Mesa Single Rectifier for over a year now. It has never *ever* given me a problem. I had traded my cab away for something, so the head was only being used for (2) shows. It worked perfectly fine. I got a cab finally (an Orange PPC-112CB). I went to go try it out when it came in, and i got no sound output from the cab at all. I changed guitar cable, speaker cable... everything. Still no output. So i thought that maybe the power tubes were not good, because when you play it seems as if there is a very very light buzzing sound following what your playing (that appears to be coming from the power tubes). Ontop of that the tubes had a blueish tint that I had never noticed before. I changed to a set of Groove Tubes 6L6 tubes, and still the same thing (even the bluish tint). Im honestly stumped. Anyone?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#2
Is your impedance matched?
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#3
I am plugging a 16ohm cab into the 8ohm output? Thats fine no?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#4
It would be less stress on the system if the ohms matched exactly. Maybe try plugging the head into an 8 ohm cab and see if it works?
#5
Quote by laneylespaul
I am plugging a 16ohm cab into the 8ohm output? Thats fine no?

Technically it's ok. I feel more comfortable knowing the impedance is the same though. Does your mesa have a 16 ohm out?

EDIT: Googled it, no 16 ohm out. I'm not sure what the issue is,

The blue glow from the tubes is just trace amounts of oxygen, nothing to worry about, most powertubes I've seen do it.
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Last edited by robertito696 at Aug 8, 2011,
#6
i mean, my old cab was a marshall 1960a 4x12 that presented a 16ohm load to the amp so i dont see how that can be an issue, regardless of the stress level wouldn't it still make sound?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#7
no it does not, it has 8ohm out or stereo 4 ohm out but i have been using it like that since i got it, and its been used like that its whole life.
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#8
Hmm, IF there is an impedance matching issue.. Output Transformer would be the issue, no? And a blueish glow from tubes is perfectly normal. Gonna quote this from a site I reference from time to time.

Glass tubes have visible glow inside them. Most audio types use oxide-coated cathodes, which glow a cheery warm orange color. Some newcomers to the tube-audio world have also noticed that some of their tubes emit a bluish-colored glow. There are TWO causes for this glow in audio power tubes; one of them is normal and harmless, the other occurs only in a bad audio tube.

1) Most glass power tubes show FLUORESCENCE GLOW. This is a very deep blue color. It can appear wherever the electrons from the cathode can strike a solid object. It is caused by minor impurities, such as cobalt, in the object. The fast-moving electrons strike the impurity molecules, excite them, and produce photons of light of a characteristic color. This is usually observed on the interior of the plate, on the surface of the mica spacers, or on the inside of the glass envelope. THIS GLOW IS HARMLESS. It is normal and does not indicate a tube failure. Enjoy it. Many people feel it improves the appearance of the tube while in operation.

2) Occasionally a tube will develop a small leak. When air gets into the tube, AND when the high plate voltage is applied, the air molecules can ionize. The glow of ionized air is quite different from the fluorescence glow above--ionized air is a strong purple color, almost pink. This color usually appears INSIDE the plate of the tube (though not always). It does not cling to surfaces, like fluorescence, but appears in the spaces BETWEEN elements. A tube showing this glow should be replaced right away, since the gas can cause the plate current to run away and (possibly) damage the amplifier.
PLEASE NOTE: some older hi-fi and guitar amplifiers, and a very few modern amplifiers, use special tubes that DEPEND on ionized gas for their normal operation.

-Some amps use mercury vapor rectifiers, such as types 83, 816, 866 or 872. These tubes glow a strong blue-purple color in normal use. They turn AC power into DC to run the other tubes.

-And occasionally, vintage and modern amplifiers use gas-discharge regulator tubes, such as types 0A2, 0B2, 0C2, 0A3, 0B3, 0C3 or 0D3.
These tubes rely on ionized gas to control a voltage tightly, and normally glow either blue-purple or pink when in normal operation. If you are unsure if these special tubes are used in your amplifier, consult with an experienced technican before replacing them.
#9
I am having a hard time understanding that last post? But if it was a problem with the output transformer, the amp would still power up? Just not make sound?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#11
Besides replacing the output transformer, is there any way to tell if that is what is deffinately causing my issue? If so how hard is changing the transformer, I am good with wiring and a soldering gun, and where can I get the part from?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#12
The output transformer is just a thought.. If you can wait till tomorrow, I can talk to my buddy, he repairs tube amps and he's a Mesa guru.. Quick question.. Will your amp turn on when you power it up, with the standby off? or do you blow the fuse?
#13
Please do, thank you. i will be in upstate new york with no cellphone reception or internet connection until Thursday, but whenever I am in town with cell reception I will be checking the forum. I am not blowing fuses, my amp is staying perfectly powered on. I did lend my amp to someone, they probably mismatched the impedance (like the wrong way, like plugging 4 ohm cab into 8ohm output) and ****ed the output transformer. *sigh*

Thanks for all the help, you have no idea how much it kills me to have a brand new cab just sitting there, without a head to play through it.
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
#14
Well, that would eliminate a bad Power Tube or Rectifier tube then, because you'd be blowing fuses.. Are you in solid state rectifier or tube rectifier mode?

EDIT: I'd think a bad solid state rectifier would result in a blown fuse as well too, though. And the more I think about it, the Mesa Transformers are pretty durable.. I'm gonna have to research it a bit more for you and see what I come up with.
Last edited by ryantombasco at Aug 8, 2011,
#15
Information BUMP
Now that I think about it.. A pre-amp tube causes hiss and noise when one is bad. Depending on the position of the tube, it's possible that it's one of the pre-amp tubes that would affect the whole amp itself, rather than one of the channels.

V1 controls both channels.
V2 and V3 control channel 2.
V4 is the effects loop
V5 is the phase inverter.

V1 would be the problem if it's a pre-amp tube. If you max out volume on the channel and your master volume, can you still faintly hear the guitar? You may or may not be able to, but that may be a possible problem to consider.

EDIT: And the more I look into it, I'm not sure if the amp would power on if it was a Transformer.. I would think that it would break the fuse but I could be wrong.
Last edited by ryantombasco at Aug 8, 2011,
#16
I had a similar problem with my MkV, although it was not hissing or humming. There was just no sound what-so-ever. What happened was that I cracked the V1 preamp tube. It may not be the same problem, but I just thought I share my experience.
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#17
Another Information BUMP:
Also, if the impedance wasn't matched correctly, you may want to have a tech. look over the caps in the amp.. That's another possibility.
#18
Hey guys, back from Upstate NY and back into WiFi. Thank you for all of the updates when I was gone,

To me it sorta makes sense for it to be the V1 tube. Do you guys think I should run to guitar center pick up a 12xa7 and change the V1 tube just to see?

I have a show friday, and if i changed the V1 tube and this thing fired back up, i would be absolutely delighted not to have to borrow a head for the show.

Also, just so you guys know I have a single rectifier so there arent actually any rectifier tubes. I did see a post from someone asking what selection my rectifier was on, just figured id let ya know that I do not have any such selection as i do not have rectifier tubes in my head.

What do you guys think? Change the 12ax7 and see what happens, or take it to an amp tech?

EDIT: Couldnt I just grab the tube that controls channel 1 and put it in the v1 spot, and then check and see if the amp is working (when on channel 2 obviously). Wouldn't that work?.. Like obviously channel one wouldn't work if that was the case, but at least I would know thats the problem?

Edit 2: Swapped the V1 tube with the V2 tube, still no sound ouput. Can we rule out the preamp tubes yet?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12
Last edited by laneylespaul at Aug 11, 2011,
#19
Bump

Anything guys?
Fender Custom Shop Telecaster
Fender Tom DeLonge Signature
Gibson ES-339
Mesa/Boogie Single Rectifier
Marshall JCM900 1960a Lead 4x12