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Fractal Audio AMP models: USA Bass 400 (MESA Bass 400)

yek

Moderator
Moderator
* EDIT: Up-to-date information is available in Yek's Guide to the Fractal Audio Amplifier Models *

USA BASS 400: based on MESA Bass 400



MESA, the famous guitar amp manufacturer, also builds bass amps. The Bass 400 and 400+ models are tube-based rack amps. There's sparse information about the 400 model and the differences between the 400 and 400+. The information below is mainly based on the 400+ model.

MESA:

“Artists often call to rave about the Bass 400+ after switching from bi- or tri- amped rigs of up to a thousand watts—exclaiming the joy of stepping forward in the mix, even to the point of leading the band. String definition so articulate that the rhythm section locks together to become one machine of unstoppable momentum.​

Traditional style rotary tone controls, which shape the Bass 400’s all-tube character are fed from dual Inputs, one for modern active basses and the other for classic passive instruments. Each of these has its own separate tube input stage and volume control. A seven-band Graphic Equalizer further details the amp’s inherent musicality, making subtle or radical tonal changes possible and footswitchable.​

No less than twelve fan-cooled 6L6 output tubes deliver 500 watts of transient power peaks with cool reliability. And this is no dirty dozen: this is a four-rack, twelve-pack of pure mean punch. You’ll be happy to know that tube life is commonly reported to range from three to five years, and often longer.”​

This amp has separate inputs for passive and active instruments and two channels.

Manual:

“CHANNEL ONE: Input 1 and Volume 1 offer a high-headroom preamp that you might find preferable for active type basses. The gain is slightly lower than Channel 2 and the tonal personality is slightly different. The Pull Bright switch built into Volume 1 can be great for funk bass, as it accentuates the harmonics above the Treble control region.​

CHANNEL TWO: Input 2 and Volume 2 recreate the classic sounds of the D-180, predecessor to your Bass 400. The gain is slightly higher and may be better suited for traditional basses than Channel One.”​

Controls on the original amp: Volume (pull: Bright, on channel 1), Master, Bass (pull: Shift) , Middle, Treble (pull: Shift), 7-band GEQ.

Manual:

“The Bass 400 Plus uses traditional type tone controls which have been especially tailored for bass, and whose ranges can be extended by use of the “Pull Shift” switches.​

The Treble control, when set high, becomes the most powerful of the three. At settings of 7 and above it will minimize the effect of the Bass and Middle, but they will become the stronger controls when the Treble is below 5. Most players find a “sweet spot” between 2 and 5 where the tonal balance is just right for them. Pulling out the Treble Shift alters its frequency center-point downward, toward the upper mid-range. (And since there is more musical energy at these frequencies, your amp will seem to get a little louder as well.) Using either Bright switch injects an extra dose of high treble.​

The Bass control is wide-ranging and using the Pull Shift can boost its power. Your Bass 400 Plus (especially when used with our speaker cabinets) can produce more true fundamental tone than just about anything else. Its bottom-end response is truly "profound" and yet it avoids boominess and muddiness.​

The Middle control is the subtlest of the three. Its purpose is filling the gap between the treble and bass frequencies.”​

We have two models of this bass amp. Model "1" has Bass Shift disabled, model "2" has Bass Shift engaged.

We have no MESA bass cabinets among our stock cabs. Find another one here.


 
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faulknier

Inspired
This has been my go to bass amp since I got the AFX. I couple it with the 4x10 Aluminum cab (Factory #67), sometimes adding a 1x15 or 8x10. I can tweak this setup to sound good in any mix.
 

stm113

Experienced
This has been my go to bass amp since I got the AFX. I couple it with the 4x10 Aluminum cab (Factory #67), sometimes adding a 1x15 or 8x10. I can tweak this setup to sound good in any mix.

Do you have any presets or tips/tricks on getting a good bass tone? I get some decent ones but always looking for something better.
 

faulknier

Inspired
Do you have any presets or tips/tricks on getting a good bass tone? I get some decent ones but always looking for something better.
Here's one preset I used for a song demo. It's dialed in for my Lakland 55-01, mostly set on the bridge pu, w/ onboard EQ flat. Scene 2 is set up with a Friedman BE that I reamped the track through for some grit and high end.

As for tips, good bass tone is "all about that midrange." Concentrate less on the sub 150hz range, and pay attention to the 150-1khz range. I've found 800hz to give my bass a "barky" sound that comes forward really well. When I used to play out live, that approach made me cut through two Marshall 100w half stacks and a LOUD drummer, w/ a less than 250w amp and one 4x10 cab.
 

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Lionheart

Guest
Concentrate less on the sub 150hz range, and pay attention to the 150-1khz range. I've found 800hz to give my bass a "barky" sound that comes forward really well.
I unfortunately have to disagree. The 140Hz to 500Hz usually needs to be heavily subdued. 500Hz to 900Hz is the famous cardboard zone. If your bass is sounding flat, then cut that zone. 80Hz to 140Hz is where the bass lives in the mix. That's the area that is very important to get right.

Sorry to completely go against your advice.
 
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Lionheart

Guest
Do you have any presets or tips/tricks on getting a good bass tone? I get some decent ones but always looking for something better.
I think that I have a generic patch using this amp. It didn’t make it on record, but I think I saved it. If I have some time tomorrow in the studio, I'll share it here.
 

faulknier

Inspired
I unfortunately have to disagree. The 140Hz to 500Hz usually needs to be heavily subdued. 500Hz to 900Hz is the famous cardboard zone. If your bass is sounding flat, then cut that zone. 80Hz to 140Hz is where the bass lives in the mix. That's the area that is very important to get right.

Sorry to completely go against your advice.
No problem here.
 
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Lionheart

Guest
Alright. So, I found the preset. A couple of notes, first. This will sound different for different players and their basses, so expect to tweak according to your gear. This was for a pop/rock song, so it probably won't work for any heavy genres. This was a "scratch" track. If I ended up using this, I would have still ran it through a couple of compressors, some EQ tweaks to fit the song, and some limiting. So, like I said in my previous post, this is a generic pop/rock preset. Use it as a foundation to build off of or if you hate it, then don't use it. :cool:
 

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