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Mesa 400/400+

they are different amps

different pre sections and different power sections

most notably the 400 uses 6x6550's (Can also use 6L6's i think, but that only gives half the power of the 6550's)

the 400+ uses 12 6L6's in the power section

either way, they are both about 300 watts output ( the 400 is only about 150 watt output with 6L6's instead of 6550's )

even at 300 watts they are still loud beasts, as most 300 watt tube heads are
 
The two are in the same general ballpark, tone-wise. In addition to the power section differences, the graphic EQ on the 400 is a six band, while the 400+ boasts a seven band. Other than that, though, I think the preamp section is quite similar. Nevertheless, the 400 which I recently picked up does sound a bit different (and somewhat better, IMHO) than the 400+'s that I have tried. I am running six 6L6's, but I am thinking about adding bias trim pots and switching to 6550's.

Tom.
 
tombowlus said:
The two are in the same general ballpark, tone-wise. In addition to the power section differences, the graphic EQ on the 400 is a six band, while the 400+ boasts a seven band. Other than that, though, I think the preamp section is quite similar. Nevertheless, the 400 which I recently picked up does sound a bit different (and somewhat better, IMHO) than the 400+'s that I have tried. I am running six 6L6's, but I am thinking about adding bias trim pots and switching to 6550's.

Tom.

Mesa told me that I could use either 6L6 or 6550 tubes without rebiasing the amp. 6L6's produce about 190 watts, and 6550's produce 240. Also, early 400+ amps have 6 band graphinc eq's just like the 400 does. I have an '86 400 and it sounds very close to the '95 400+ I used to have.
 

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