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Availability:
In Stock.
Arrives
Thursday, Oct 29
At a glance
- Condition
- New
- Model
- M81
- Dimensions
- 2.5"D x 5.5"W x 4.5"H
- Weight
- 0.5 lb
- Output Wattage
- 15 Watts
- Batteries
- 1 9V batteries required.
- Connector Type
- 6.35mm Jack
- Works with
- Double Bass
Features 4
- Separate INPUT & OUTPUT level controls
- 3-band EQ section with sweep able midrange
- Studio-quality Direct Out
- Model Number: M81
Description
The MXR Bass Preamp combines a pristine bass preamp with a studio-quality Direct Out in a Phase 90-sized box, providing clear tone without hogging precious pedalboard space. Use it to add a new voice to an old passive bass, sweeten up any amp, or put some special sauce on a particular song. Dial it in just the way you want it and send it straight to the house—pre or post-EQ—with the built-in Direct Out. The Bass Preamp features separate Input and Output level controls and a 3-band EQ section with sweepable midrange—from 250hz to 1khz—for extensive tonal flexibility. It's all delivered super clean with high headroom thanks to our own Constant Headroom Technology™, and you can use the PRE/POST EQ switch to set whether or not your Direct Out signal is affected by the Bass Preamp's EQ section. And of course, the Bass Preamp features a GROUND LIFT switch in case you encounter ground loop hum. The Bass Preamp is factory preset to operate in ¼" out buffered bypass and Direct Out active. For players who only want to use the ¼" out, there are two internal switches that disable the Direct Out and ¼" out buffered bypass for true ¼" out bypass mode.
Specs 11
| Brand | MXR |
|---|---|
| Output Wattage | 15 Watts |
| Product Dimensions | 2.5"D x 5.5"W x 4.5"H |
| Item Weight | 0.5 Pounds |
| Item model number | M81 |
| Batteries | 1 9V batteries required. |
| Connector Type | 6.35mm Jack |
| Hardware Interface | HP-HSC |
| Signal Format | Analog |
| Power Source | Corded Electric |
| Voltage | 9 Volts (DC) |
No specs match.
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Thursday, Oct 29
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Fantastic Bass Preamp Pedal
I tried a lot of preamps. The MXR M81 has all these features that made me buy and keep it. - Sounds great and doesn't change the character of my bass of amp. - Can run on battery, phantom power or standard A/C adapter. - DI on board with pre/post switch and ground lift. - Plenty of headroom. I can run direct into a power amp if needed. - Small form factor (like a Phase 90). To me this sounds a lot like a Sadowsky preamp. The MXR M81 is smaller than the Sadowsky SBP-1 but has sweepable mids and more headroom. It's more feature rich than the smaller Sadowsky SBP-2 having the advantage of a DI with phantom power and can run on a 9V battery or A/C adapter. Finally the MXR M81 is cheaper than both Sadowsky preamps. Great preamp!
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Reviewed in the United States on June 11, 2020 by J. D. Wyatt
Perfect for when no amp is required. 5 stars
Fantastic perfect for my bass
Reviewed in the United States on February 4, 2026 by Amazon Customer
Does The Job
Great preamp with nice DI out signal. I swapped out my Mighty Mite soapbar pickups for EMG's and though they have active circuitry they have a passive feel. So the preamp boosts the signal well and the onboard eq allows for decent tone shaping. Takes some "playing around" to get the sound you want. Would recommend.
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Reviewed in the United States on January 18, 2025 by YulJ
MXR M81: Great for Acoustic Guitars too.
Although this is marketed as a bass preamp I acquired it for my Maton 225 acoustic-electric guitar to play into a Fender 65 Deluxe tube amp. There are dedicated acoustic preamps out there but all I wanted was something rugged, basic and versatile. The MXR M81 has a very high impedance input, good selection of tone controls, and outputs for either a guitar amp or a balanced output for a PA. The mid control is especially useful as you can select the frequency and boost or cut it. Fender blackface style amps have a big dip in the guitar's mid frequencies (or a boost in the bass and high frequencies if you look at it another way) so I've been able to dial in a tone setup that compensates for this. It also worked well as a clean boost for a Strat. Alternatively it could be used as a buffer at the start of a pedalboard; like the MXR Six Band EQ and the MXR Dyna-Comp I think it is a really very useful piece of kit. Bought off Amazon direct and got very good service from the seller.
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Reviewed in the United States on September 4, 2015 by Jimmy Rowe
A very high-performance bass preamp in a smallish package
This is a very well-featured, very high-performance, and fairly small pedal (for a DI/XLR output pedal with EQ and more, specifically made for bass guitar). It sounds great. It is true bypass, and I have no hiss from this or any other pedal (on a board with 6 total). I enjoy the way it handles the midrange EQ control, and I also love the two volume controls (one for incoming, one for outgoing). I play through the in-house PA system in a venue that seats 300 or so (at capacity). It's a church venue. I love being able to control my on-stage volume independent of the in-house PA volume. Would definitely buy again. If I lost all my pedals for whatever reason, but could only replace three, this would definitely be on the list.
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Reviewed in the United States on October 18, 2014 by Vince F
Good Sound, Bad Quality
Great sounding pedal, but it fried on my pedal board after 4 months.
Reviewed in the United States on February 20, 2026 by Zme
Gives me a very satisfying amount of control of my bass tone
I got this for playing a few different bass guitars direct and with headphones, so I can't speak to what this device can do for playing live, but I absolutely love it. I have an Ibanez Mikro bass (extra short scale) that I improved by adding Seymour Duncan pickups, but it still sounded a bit thin to my ears. This preamp completely kicks it up to a level of power and versatility that vindicates my sticking with this somewhat silly little bass. I can boost the low and low-midrange without losing crispness and clarity. And I don't have to use the tone controls on the bass, which always strike me as unsatisfactory. I'd previously tried a "bass boost" pedal that was basically equivalent to overusing the tone control and then amplifying that low but dead sound to dubious effect. Another of my basses is an entry level fretless with stock pickups that I haven't upgraded yet. This pedal does greatly improve the sound, but the effect does seem to be dependent on starting with quality pickups for the best result, so it doesn't magically fix an inherently poor tone. My third bass is an old 60s era Japanese EB-2 clone, with one of those lovely mudbucker pickups. That pickup is a force of nature. It basically turns you into a god of thunder, but it sure is muddy. I've always wanted to find the right way to enhance the high end a bit to give the sound a bit more definition or something. This pedal enables me to do that very nicely. Moral of story: if you keep your bass's tone control all the way open, you can use this pedal to shape the sound without losing anything, as long as your pickups are providing a good enough starting point. There is a slight learning curve, such as using the dip switches hidden behind the battery cover, learning whether to use the direct output or not, but it's not difficult. The only problem is that the pedal does not come with a proper manual that explains any of this, so you've got to search online for the manual.
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Reviewed in the United States on December 31, 2023 by Amazon Customer
Good item
Sounds good. A little bit of hiss but if you keep the output down and push the input, then you get a clean, strong signal
Reviewed in the United States on January 31, 2025 by allen