Mesa 400 vs. Mesa 400+

[eyeballkid]

so i searched for this but couldnt find the thread that I saw before that explained this..

Whats the real differences?
Ive heard some say that one breaks up better than the other or has better overdrive but dont remember which?

I remember some thread where folks were saying definately get one over the other if you can..

Ive seem to ALWAYS see these (either one) being played with the lowest freq. of the EQ really bumped... do they have a lacking low end otherwise?

reliability?
tone?
in general, what do you all think of em?
basically I like a roaring amp but one that still has a full bodied beautiful clean tone. My board is a tuner, a reverb, and 6-8 fuzzes and overdrive pedals.

discuss.
and thanks.

[Chef]

Well...
the original 400 had 6 tube, that I believe were not 6L6...but were, later, switched to 6L6.
the 400+ has 12 6L6, and later ones had one more band on the graphic eq, I believe.

I've had both, and found the 400 a tad warmer and cleaner, but, this could easily have been due to power or pre tube types and quality, and/or bias/setup.

I did not find either to be "thin," however, I did not find enough clean headroom in either, and moved on.

[BBQV]

In my opinion, the 400 is close to perfect. It's not as powerful as the 400+ (somewhere around 200W), which means you can push it into distortion without disintegrating the room...
The 400+ is slightly meaner soundwise, sharper somehow. It cuts through everything and packs some serious punch. I've never came across a louder amp!
Which one's the better amp depends on your needs and preferences. I'd go with the 400 because of the sligtly softer sound qualities, but if it's power you want you should get a 400+.

[rekesbass]

both amps produce 300 watts(I think it's closer to 280). the 400 had 6 6550's(aprox.50w\tube). the 400+ had 12 6l6's(aprox.25w\tube) and an extra band on the graphic e.q...any 400 with 6l6's is not running at full power although it does work..

[anderbass]

Originally Posted by rekesbass

both amps produce 300 watts(I think it's closer to 280).

My very knowledgeable amp tech proved the 400 (non+) power transformer limits a really good set of 6550's to only 180 watt max clean output. It would probably have a 300 watt peak rating, compared to the 400+ peak output of near 500 watt.

(quoted thread)
Mesa 400...6550/KT88?

Originally Posted by timv

I have a couple responses to this questions floating around here somewhere but I will explain what I have found and tested....

I've tried this experiment on an old 400, a d-180 and an old m-190 power amp. These 3 amps all show 6550's in the original catalogs but were eventually running 6L6's. I added adjustable bias to all 3 and tried a few sets of tubes and measured full clean power out. This is all based on measurements and electronics formulas, not sound, but gives you an idea of what I tested.

I ran a nice set of GE 6550's, which are now in my 400ps, a set of EH6550's, some jj 6L6's and a few others.

The GE's topped out the power output at about 180 watts before the first sign of distortion on my oscilloscope.

The JJ's were next at about 170 watts so the 6550's only put out about 10 more watts.

I did run a nice set of sylvania str 415 6L6's which were around the 160-170 watt range.

The other tubes were all around the 160-170 mark.

I think I ran some sovtek 5881's too and got around 150.

These are just test numbers. I think 6550's or KT88's would run a bit cleaner and probably have a little more low end than 6L6's.
I say try both types, might want adjustable bias to make sure you are getting the most out of the tubes, and listen to what your ears like the most.

Have fun......

[NecroticImbecil]

I won't claim to be an expert, my opinions are just that and based solely on my own hearing and tastes. My qualification:



I did not have a bias mod performed on any of these amps. Common wisdom is that it should be done whichever one you own. With JJ KT88s, my 400 sounded very similar to my 400+, probably impossible to tell the difference in a band setting. My 400+ was very clean, but had a "flavored" or "colored" sound which was great for rock. All these amps, and even the Mpulse head I tried out have something of this flavor. My 400+ did not noticeably break up in normal use, with the Master at 3-5, CH1 at 4 and CH 2 at 2-3. Cranking the preamp volumes produced some pretty bad sounding distortion.

With 6L6s, the 400 sounded less full than the 400+ or the 400 with Kt88s. Not thin, but thinner. Still good though. It broke up much earlier, becoming tough to keep clean at loud volumes. Sounded awesome though, mean roaring distortion. For this reason I preferred it to the 400+, even though it only goes down to 4 Ohms where the + goes to 2. I have heard reports though that it is safe to run a 400 at 2 Ohms, but I never did it for an extended time. Worked fine for the hour I tried it though.

Regarding the low end comment, I was not happy with the performance of the 400+ with my 5 string, which is tuned down a step to a low A. I can't say for sure how much was the amp and how much was the speakers, since I changed the whole rig once I got into 5 string playing. I'd been using Ampeg and Mesa 15"s which sounded great with the 400+ for 4 string playing, awesome midrange and bite, but didn't convey the lows very well. I switched to something more powerful and clear sounding. For a while I used a solid state amp for the lows, which worked well but made for a complicated setup.