MXR M81 Bass Preamp Pedal Reviews

I use this whenever I need a silent sound stage (e.g., church, small bars, pit orchestra, etc.) and it has just taken a licking and kept on ticking. I have it on pedal board now, but for a long time, the phantom power feature was so incredibly nice.

The MXR M81 does exactly what I want it to do! I mostly play in a church worship team these days. We all play directly into the house system. My bass is a 5 string Ibanez with Aguilar pickups. Though I have a pedalboard with a number of affects, there is no need bring it in to use just the preamp and tuner. However, I felt like something was missing plugging into a DI and making tone adjustments on the instrument. So after reading a few reviews, I got this MXR preamp that sits alone between my bass and the house DI. I turned off my bass' active preamp switch and let the M81 do it's job. I wanted a way to boost the low frequency without losing a distinct attack. The M81 did it for me. That's it. That's all I wanted and that's all it does. Very simple and very effective!

Most of my basses have high-end onboard preamps, but a couple do not have any preamp at all. I bought this pedal to "level the playing field" from a volume standpoint, as well as give my fully passive basses the same tonal flexibility as their preamp-equipped brethren. This pedal hits it out of the park, and then some.
First off, like all MXR pedals, this beast is built like a tank. The knobs are nice and sturdy, and the pots are firm.
Secondly, with all knobs at 12 o'clock, everything is perfectly flat (versus your original signal) as it should be. Your natural sound is not "colored" at all, until you start tweaking outside 12 o'clock.
Third, the EQ is both effective without any spikes, and CLEAN, free of distortion.
Fourth, I love me a good sweepable midrange.
Fifth, the ability to plug in an XLR cable and use this to drive your tone directly to a PA or recording interface is beautiful. Basically, you got yourself a clean SansAmp here, if you want it.
Finally, the price is hard to beat.
All in all, if you are in the market for an off-board preamp, this is what you want.

I play a Fender American Pro Jazz Bass. The bass sounds great but I noticed on the silent stage at our church did not have strong output. To compensate, I bought the M81. Problem solved! Additionally, it is built like a tank and records well. Be aware it will not color your tone like a Tech 21 or Darkglass pedal but if you like the sound of your instrument, you can't go wrong with this pedal.

I originally bought this preamp simply because I love mxr pedals. I know that sounds shallow but I'm sure I am not the only gear head thats ever done that. I did not know much about it. I did not do much research on it, as I typicaly do with all my gear, especially pedals because I have so many of them. I needed a preamp for my new pedalboard so I chose this one. It turned out to be an excellent investment. As a preamp it is very effective at giving my signal that extra humph but I mainly used it to help shape my passive "PJ" bass tone before it hits the rest of the effects pedals. I especially like the "line out" knob which gives the tone some guts. I have it after the mxr bass compressor and before everything else.
This is such a good preamp that I want to buy an extra one just in case I lose the one I have or it gets stolen.
My advise is, dont even bother looking somewhere else for a bass preamp. This is a killer preamp at this price point and in this tiny footprint. MXR makes the best pedals out there.

OK, I've been out of the gigging loop for many years... I did get a light GK bass amp... But I'm still lugging alot of stuff around... After some research I pulled the trigger on this gizmo... First night at practice I brought my amp, but left it in my Jeep... I wasn't sure what to expect... I hooked up the DI into our board... Amazing!! It worked as I never thought it would! The band mates were also happy! We could here the bass through the PA! I've still some tweaking to dial in my sound... I'm very content with this product.. Thank you Sweetwater for having many of these types of items to compare!
Todd

I’ve always been an active preamp type of player. I was gifted an amazing passive Fender Jazz Bass, and fell in love with the natural tone of the bass. The only thing I wanted was just a slight boost of lows and a slight boost of signal, considering I was used to the active preamps. After searching for a pedal, I took a leap and purchased this one. All the reviews said it was one of the most transparent bass preamp pedals with the built in DI.
When I first opened the box, I noticed it was a fairly small pedal. That’s important to me because all the other ones I considered were huge, and I’m not trying to be the bass player with a guitarists’ pedalboard. I use 3 pedals, including the M81, and I think my pedalboard is complete, and it can fit in a toiletry bag.
I plugged it up in my studio first, dialed everything to 12 o’clock, engaged the pedal, strummed my bass, and heard absolutely no difference in sound. I played a low Eb (I tune down a half step), and switched the pedal on and off, and heard no difference. That by itself made the pedal worth it. I then proceed to boost the lows to about 1 o’clock, and the output and input to a little less than 1 o’clock, and my tone was literally complete. I then plugged it into my interface to check it out on my DAW. The result was super clean, with a boost in gain, a boost in lows, and I trimmed the highs just a bit. Glorious.
I did the same thing at my gig that night where I play 6 sets a night 5 nights a week. I use in ears as well as an amp (as a sub pretty much), and the tone is just....I wish I could describe it. With the M81, I’ve been able to slightly shape the natural tone of my bass and have enjoyed playing it much more than ever before. Because of the clean DI function, I can better shape the tone I give to the FOH engineer, and we can all be happy, verses going through a different DI with no EQ or tone shaping, and have a different bass tone going through the house than what I’m trying to put out. If you like the tone of your bass, and want to shape it to how you like verses getting a bass with an active preamp that sounds more like the preamp than the bass. I could’ve saved a lot of money had I purchased this preamp a long time ago...

Impressive piece. Lets me increase the low and mids without distorting the sound in any way. Practice rig is Hartke HA3500 & Eden xlt 4x12. And I gig with a Peavy Mini max 500watt @ 4ohm and a Hartke 2x10 HYdrive cab. I highly recommend this pedal for a non bank breaking Preamp.

The MXR M81 is a must for anyone with a home studio. It will make a difference to any bass track recording, plus it has a balanced XLR output! I ve used to record bass using the recording out on a roland cube bass amp. I notice that that sometimes I just didnt get the clear bass tone I wanted. Then, I recorded bass using a bass drum mic and a passive radial DI box( which it made a diference). Im always looking for ways to improve my recordings. Then I decide to get the MXR M81 bass pre amp. Right away I liked the way it cuts thru my recordings. You will hear the difference.

Great preamp in a small package. I use this on my pedal board mainly to control tone,and not as a DI, so I can't comment on that. It's clean, quiet, and provides a wide variety of tones. I like to scoop the mids a bit, and this does that by simply setting both the bass & treble at 3;00 and leaving the mids flat or slightly boosted at 800K. It's a little pricey, but it gives me the sound I want and seems to be well made,

this bass preamp gives a get selection of tonality to make any bass you play sound their best.

What a great sounding pre-amp/E.Q. this thing is! The mid-range control, being semi-parametric, is great for finding that sweet spot in your tone, be it boost OR cut (in my case, a -7-10db cut around 600hz). The bass and treble controls a shelving types, so they offer quite a warmth and sparkle to your tone as well. Do they add thunder or snap? Not really in my application, which is as a "real" pre-amp, but they are quite usable and offer a very wide range of boost or cut.

As I've said, I'm using the M81 as a true pre-amp; that is to EQ the instrument and get the gain up enough to drive a power amp, rather than just change tones around and then plug into an amp- First, it is one of the two real EQ sections I have in my rig (the second being an EMG EXB ("smiley face EQ) built into a stomp box case and selectable rather than hacking apart my instrument. the other "real" pre-amp duty this thing offers is output level. It is great for D.I.'ing into the board (for either recording or live). Output level is quite amazing- I use it to drive my power amp (and SWR Stereo-800) which in turn drives an Ampeg SVT810E speaker. I have run the input and output controls full up, and this thing doesn't clip! The idea of MXR's "constant headroom technology" is something that adds a great amount of value to this pedal. Get one!!!

This is a fabulous pedal. It holds a very wide range of tone shaping capability, and it does very little to color your bass' tone. The mid sweep is a wonderful feature, and the separate input/output levels really help dial in the right sound. I even use the M81 as a sort of boost pedal when I'm playing through my M89 overdrive; the it really brings out the crunch when I raise the mids and/or treble. I play an active Ibanez.

I received this in early June and have already used it on three gigs with my Fender P-bass (passive). I've been searching for a small pedal preamp that I can mount on my pedal board. Most of the ones out in the market and large in size. The other larger ones I own are great but they're too large in size for my pedal board. I really like how the EQ on this pedal is voiced, and its very quiet. Don't hesitate. Get one. You will not be disappointed. MXR, you hit one out of the park with this one. Bravo!

I've had this MXR M-81 Bass Preamp a few years now and all I can say is…. WOW!!! I doesn't color your sound, but what it does is amazing! The EQ is perfect! With its sweepable mid's and the clarity of the bass and treble there's no room or recording session it can't handle! I never leave home without it! You never know when something might happen to your amp or that promised back line amp is a real POS. With it power options (especially the phantom power) it's amazing!

This really did the trick for the bass player I jam with to get good direct sounds. Works well with recording or live. Much more reasonably priced than a lot of similar devices. Another MXR winner.

For years the only D.I. I would even consider plugging into has been the Tech 21 SansAmp Bass Driver, that's what's in the studios, they sound great and they're bulletproof in terms of durability. I wanted to what else was out there and MXR's pedals have been awesome lately so I figured this was a safe bet.

It's not as good as the Tech 21 but it's definitely a close 2nd. As far as just a straight d.i. It's rock solid the sound is great but just not as nuanced as the Tech 21...the MXR just sounds a little flatter.

It's a solid pedal all around and I am just more accustomed to the Tech 21 but for the money and with the sound it's great.

Let me start by saying that my amp set up is a GK 1001RB with a 4X10 & 1-15 Neo cab system, playing Fender J & P basses. I also play keyboard bass through this same system. It sounds great, but I always felt like just something was missing in my sound..... it was this MXR bass preamp, what a wonderful piece of equipment for any bassist. I also use it with my GK MB series amp, where it does indeed do wonders there too. If you are looking for a great bass preamp for a good price along with durability & function, this has worked just fantastic for me!

MXR really nailed it with this. Great DI, pre/post switch is perfect for matching different line level requirements. I tried the MXR M80 and Mooer DI, but couldn't get a good signal going line in to audio interface. EQ is great too, it replaced my parametric. I also love the compact size. I love this pedal!

I needed a good Bass Preamp to add to the end of my pedal chain on my pedal board, to boost the signal when playing metal and hard rock. I've seen boost pedals and even the Darkglass Electronics Microtubes B7K. I love that one, but that's a little too rich for my blood. Then I discovered the MXR M81. I love the EQ features. It definitely gives me the tone I was looking for when I need it.
I highly recommend it :)