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NAD: Mesa Boogie Bass 400+ score!

Tonegasm

Tonegasm

Fast cars and vintage guitars.
Mar 22, 2010
2,988
914
NJ
#1
Scored this Mesa Boogie Bass 400+ locally. It's not functioning due to a blown fuse, so I took a gamble on it. Brought it home, popped it open and the first thing I noticed was that one power tube had a hairline crack in the glass and the glass was milky. Went to remove it and it shattered. That was probably the culprit that blew the fuse. Gotta admit - these things are built like tanks!

I'll give it a thorough in-depth inspection and cleaning, install the new 6L6 tube, new fuse, and lube the pots tomorrow. Should be good to go to give up thick, rich, tubey goodness.

Anyone know how to date these things? Can't find any signs of a handwritten date on the inside, only the serial number on the label.

Photos:

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#6
azwhofan said:
man oh man, that looks real clean!! congrats on what promises to be a stellar score!
Click to expand...
Thanks! It's got a bit of wear underneath. The previous owner never had it in a rack. I used a permanent black marker and colored in what I could. Looks great. Thinking about picking up a used 4U rack to protect it from here on forward.

Can't wait to fire it up tomorrow.
 
#7
Lublin said:
I'll give it a thorough in-depth inspection and cleaning, install the new 6L6 tube, new fuse, and lube the pots tomorrow. ]
Click to expand...

It's seldom as simple as you make out. The new tube has to work with all the others. If it's characteristic are off from the others you could end up with another blown tube or perhaps a whole bank. Do you have experience working with a live tube chassis?
 
#9
What tubes are in it now? Are they all Mesa branded? According to Mesa you can swap out tubes as you need as long as they are Mesa tubes without biasing. Assuming the rest are Mesa branded as well...

Anywho, I love my 400+. It's a really sweet amp! I can't wait to gig it this weekend.
 
#13
the tubes need to match front to back. each pair needs to match. the mesa tubes are color coded. if they say yellow you need another mesa yellow. if they say blue then blue. red/red. so on and so forth. would prolly be best to just order 2 new tubes and replace both. they come in packs paired together. you can even find used ones on ebay. they should all be the same color code already. if so just buy a pack of the same color code and you will have a spare tube leftover.
 
#14
Excellent info - thank you. I do think I have a matched pair of either EH's or JJ's at home. I'll replace the bad tube and the one in front of it in the 400+ and report back tonight.
kilgoja said:
the tubes need to match front to back. each pair needs to match. the mesa tubes are color coded. if they say yellow you need another mesa yellow. if they say blue then blue. red/red. so on and so forth. would prolly be best to just order 2 new tubes and replace both. they come in packs paired together. you can even find used ones on ebay. they should all be the same color code already. if so just buy a pack of the same color code and you will have a spare tube leftover.
Click to expand...
 
#15
Lublin said:
...

Anyone know how to date these things? Can't find any signs of a handwritten date on the inside, only the serial number on the label.

...
Click to expand...

Look for date codes on the transformers and electrolytic capacitors (or post close-up photos of the markings on them for us to ponder). That would get you on the ballpark.

Also, if you call Mesa and give them the serial number, they might be able to tell you.
 
#16
BillyB_from_LZ said:
Look for date codes on the transformers and electrolytic capacitors (or post close-up photos of the markings on them for us to ponder). That would get you on the ballpark.

Also, if you call Mesa and give them the serial number, they might be able to tell you.
Click to expand...
I emailed Mesa. - no response yet (it was late at night).

I'll take a look at the component codes before I re-tube/re-fuse and give it a go tonight.
 

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