400+ Tube layout

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softcover
Bottle Rocket
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Joined: Thu Oct 21, 2010 9:22 am

400+ Tube layout

Post by softcover » Thu Oct 21, 2010 9:44 am

Hello everybody!

It is time to retube my bass 400+ head. I already got new MESA tubes (preamp and power) and a few questions come to me before replacing them.

1.- I have read that the preamp tubes must be placed in a certain order (less noisy to most noisy) so the preamp noise is minimized.
2.- The power amp tubes come packed in matched pairs but I can not find (i have looked through this forum and internet, I promise) how they are laid out in the amp. There are 2 "rows" of 6 tubes and common sense tells me that each "column" is a pair, but I could not check this anywhere. (As i do not live in America, calling Mesa Boogie can cost me more than the tubes themselves, so it is not an option).

I asked the guy I bought the tubes from and he told me that all mesa tubes come previously checked and that there is no problem in placing them in any order (preamp or power amp). I trust him but I would like to make sure if possible.

So: Do I have to worry about tube order / pair placement...? If so, where can I find the layout so i can identify the "pairs"?

Thank you all in advance.

Cheers!!

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seventhsunbass
Bottle Rocket
Posts: 6
Joined: Sun Jan 24, 2010 8:29 am
Location: Maryland

Re: 400+ Tube layout

Post by seventhsunbass » Wed Nov 03, 2010 3:11 am

If you read the back of the 6l6 box, you see the layout should be ordered by color alternating.
Mesa Boogie 400+ (#1)
Mesa Boogie 400+ (#2)
Mesa Diesel 1-15"
Mesa Diesel 1-15"
Mesa Roadready 1516BE
Meas Roadready 2-10"
Mesa Roadready 1-15"
up next.......Buster!

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cho
Mark III
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Joined: Thu Sep 25, 2008 2:55 pm

Re: 400+ Tube layout

Post by cho » Sat Jul 02, 2011 2:29 pm

bump. I have the same question: Which are the pairs on a Boogie 400+?

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cho
Mark III
Posts: 247
Joined: Thu Sep 25, 2008 2:55 pm

Re: 400+ Tube layout

Post by cho » Sat Jul 02, 2011 11:07 pm

For those who are interested, I called Boogie and found the answer:

Tube pairs are the front and back tube in each position. There are 6 tubes in the front, 6 in back, each front/back combination being the pair.

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