Mesa M-Pulse 600

[drbassman]

I'm glad you finally found a combination that works for you.

Yeah, it was probably harder than it needed to be, but I had the wrong speakers for awhile and a wrong amp or two.  So, it took me some time to sort it out.  If I had stayed with the Scout and my old speakers, I would have been just fine!  My mistake was changing speakers and amps at the same time and neither one really was what I wanted to hear.  Live and learn!

[drbassman]

Played a gig with the Mesa MP 600 and Scout cabs.  It was wonderful!  I loved everything I heard from the rig.  A drummer from another local band was there and came up to me afterward to tell how great the rig sounded.  I was happy to hear it from a unbiased listener.

[georgestrings]

That's cool - I've long considered my M-p 600 to be a keeper...


   - georgestrings

[drbassman]

That's cool - I've long considered my M-p 600 to be a keeper...


   - georgestrings

Besides the abundance of EQ and other adjustments, the built in compression is fantastic.  A great amp that they should still be making IMHO.

[drbassman]

Well, I've had my M-Pulse 600 since September, 6 months, and I'm still in love with it.  I know it's a shock, but I won't be flipping it.  In fact, I'm thinking of acquiring another one as a back up since they don't make them any more.  It just a great sounding amp!

[Psycho Bass Guy]

It never ceases to amaze me how Mesa can make such great sounding bass amps with transistor output sections, and then slap a bad sounding guitar tube power section in their tube bass amps.

[drbassman]

It never ceases to amaze me how Mesa can make such great sounding bass amps with transistor output sections, and then slap a bad sounding guitar tube power section in their tube bass amps.

You are so right. After months of struggling with the Prodigy, it took me less than a week to dial in a fantastic sound from the M-Pulse.  My little Scout has a similar ease of operation and tone quality, but I feel the built-in compression makes the M-Pulse a total winner and best all around amp for my needs and taste.  I just couldn't get the Prodigy to perform properly.

[Dave W]

It never ceases to amaze me how Mesa can make such great sounding bass amps with transistor output sections, and then slap a bad sounding guitar tube power section in their tube bass amps.

You know circuits and I don't, but when I gigged with my Bass 400+ I got nothing but compliments from other bassists.

[Psycho Bass Guy]

You can sorta get around the voicing if you boost the lows on the graphic EQ enough, which is active and post-preamp tone stack, about 6-8db, but the inherent "flat" response of the power amp, no tone controls at all, signal injected post preamp is a steep low end rolloff starting at 80 Hz. It's a function of the stage coupling caps they use and a relatively high primary impedance output transformer. Most folks never miss true lows, but it is what separates their sound from everyone else. It's also a HUGE tube life saver and a sneaky way to make sure that tube imbalances that would be blowing fuses in other tube bass amps are much harder to cause. The lower the frequencies the output section has to pass, the greater their current output, and high current is what stresses all amps tube or s/s. It has a nice tone, but it's literally the Showman tone stack with some frequency shifting in the pull knobs being fed into a narrow bandwidth power amp.

[Dave W]

Thanks for the explanation. Sounds like it was intentionally designed to operate this way.

At least I know what a Showman tone stack is.

[Psycho Bass Guy]

It's wholly intentional, of the bean-counter intent; Mesa set it up this way for the same reason it ships ALL its tube amps with the tubes biased VERY cold, to minimize warranty claims both on the tubes and the amps.  You could pull half the tubes from a 400+ and if the amp were set up for full power and easily get the same amount of power (about 180 watts) that one with a full tube complement factory stock puts out. They're good amps, but people should be aware of their characteristics, which Mesa doesn't like to trumpet. If you read Bass Gear magazine, all you need to do is look at the frequency response plot published in the latest issue of the Prodigy and Strategy amps to see that they also have this inherent low end rolloff.  Fender didn't do it in the designs that ALL of Mesa's amps come from, but Fender also had a much better supply of power tubes of higher quality.

It's not a "tube amp thing" either. I have seen few self proclaimed experts chiming in on TB that low end rolloff is part of using an output transformer ...except low frequencies are the easiest thing for them to pass until you get below 10Hz, and no speaker is going to be hitting that, nor any instrument putting it out anyway. (Highs above about 2-5kHz require complex interleaving of the OT windings so that the transformer's own inductance doesn't muffle and roll them off, but that's another topic).

My current go-to amp is my Mesa 400+ and while it isn't quite the monster that some of my others are, I feel that I've finally got it to sound and perform the way I like, so I'm not dogging Mesa. I love that little bugger and it's a nice living room compromise between my B-15 and SVT and bigger tube amps. I just have to keep that 40Hz slider on the graphic EQ pretty much near full boost just to make the amp be honest about what it puts out. I do love the odd midrange character the amp has, and it's not hard to hear Cliff Burton's tone (what was audible anyway) in the 400+, which was the second generation of the amps he played in Metallica, early D-180's and Bass 400's. That low end rolloff may have been what inspired him to put that mudbucker in the neck position of his Rick 4001.

[drbassman]

Crap, the last thing I want in a bass amp is low end roll off!  Geez!!!!   

[Psycho Bass Guy]

Starting at around 100 Hz, but actually "cornered" at 80 Hz, Mesa tube bass (and guitar) amps have a 12dB per octave rolloff. That's steeper than some crossovers.

[drbassman]

Starting at around 100 Hz, but actually "cornered" at 80 Hz, Mesa tube bass (and guitar) amps have a 12dB per octave rolloff. That's steeper than some crossovers.

Makes no sense to me.   

[Psycho Bass Guy]

My guess is money and tradition. It really does make the amps WAY more stable. Lows are harder to have with tube amps that may or may not have decent output tubes. Since nobody has complained over the years (mainly because most bass cabs can't do much that low anyway and even fewer bass players could tell if they did) and even Bass Gear raved about the amps' sound, I figure Mesa sees no reason to change it.  The filter is set up in the stage coupling. It's not in the preamp, so any direct out recordings made off the amp will have the lows that are there present. It's only the power amp itself where they are missing, which is why their tube/ss amps sound so different from their all tube amps. Since Mesa considers that part of their tube amp sonic signature, I doubt it will ever change. It's a shame, but Randall clearly has had the Kool Aid that says fundamental frequencies aren't important to electric bassists or even if they are, will cause more problems onstage than their tone is worth, which is also BS; most bass feedback is in the lower midrange (100-400Hz) and bleed will happen from PA subwoofers just as easily as it will stage backline. Lots of guitar-centric amp designers treat bass amps that way and then wonder why everyone still prefers the old SVT for tube bass sound.