PJB (Phil Jones Bass)

X4 Nanobass Multi-Instrument Combo Amp

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We ship worldwide! (Read this)

To the Continental USA
  • X4 Nanobass Multi-Instrument Combo Amp, top 3/4 view Black
  • X4 Nanobass Multi-Instrument Combo Amp, top 3/4 view RED
  • X4 Nanobass Multi-Instrument Combo Amp, side 3/4 view WHITE
  • X4 Nanobass Multi-Instrument Combo Amp, front view BLACK
  • X4 Nanobass Multi-Instrument Combo Amp, top view BLACK
  • X4 Nanobass Multi-Instrument Combo Amp, top 3/4 view RED
  • X4 Nanobass Multi-Instrument Combo Amp, back view BLACK
  • X4 Nanobass Multi-Instrument Combo Amp, front view WHITE
Our Low Price: $359.99

Price shown may adjust with options selected below (if applicable)


We were among the very first dealers to bring Phil Jones amps to the US market, and we've brought them back on board!

I'll be updating the specs on this amp with my personal descriptions very soon. In the meantime, here's the information as provided by PJB.


Lightest Portable Tone-To-Go, A Mini Marvel

Nanotechnology breaks the sound barrier with the X4 Nanobass Multi Instrument Combo Amplifier, which is the most compact and portable combo amplifier ever designed by Phil Jones Bass for desktop and practice applications. It is a highly efficient mini engineering marvel that redefines transportability and “Tone To Go”.  It is a 35 Watt amplifier with a 4” speaker and 3 Band EQ that not only rocks with bass; it will also provide dazzling tone for other instruments including guitar, ukulele, violin, and electronic drums.

The practical and versatile design includes an auxiliary input compatible with iPads, iPods and drum machines, and is Bluetooth equipped for music listening enjoyment and other applications.  PJB’s proprietary NeoPower 4-inch speaker delivers full frequency range that achieves ultimate tonal clarity and transparency for instruments as well as high-fidelity sound to any source fed into the auxiliary and Bluetooth inputs.

The X4 weighs just over 5 lbs and is small enough to fit in a backpack. It is available in Black, Red, and White colors. As with all products in the PJB family it is constructed from the highest quality materials and built to provide years of enjoyment and “Tone To Go” anywhere in the world with its built in worldwide AC voltage input.



  • PJB N52 Neo-Power 4 inch speaker driver
  • 35 watts Digital Amp with DSP-based active crossover and dynamic range control
  • PJB 3 Band EQ.
  • Stereo Aux input for Drum machine or iPod/Smart phone player.
  • Bluetooth5.0 (aptX HD)
  • Worldwide AC voltage Input. (100~240V)
Model X-4
Amplifier Digital with DSP
Power Output  35 Watts
Speaker 1 x N52 Neo-Power 4inch speaker driver
Frequency Response  72Hz – 15KHz

3 Band EQ, Bass shelf 100Hz, +/-15dB; Mid 1KHz Bandwidth 120Hz-10Kz, +/-15dB; Treble shelf 10KHz, +/-15dB

Input AUX-Input Jack, Bluetooth5.0 (aptX HD)
Output Headphone-Out
Input Levels Instrument:240 mV – 2 V; AUX:300mV(MAX); Bluetooth:500mFFS
Power AC 100-240V/50-60Hz,6 ft Angle Plug AC Power Cord
(W x D x H)
6.3 x 7.9 x 7.8 inch
Weight 5.3 lbs

Product Manual

Need to figure out some of the more in-depth features of this product? Here's a copy of the manual, in PDF format, here.

You may wish to visit the manufacturer's website to see if a more recent version is available.


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Warranty Information

Warranty Information
PJB amplifiers carry a 2 years limited warranty on parts and labor.

Products must be purchased from an authorized PJB dealer.

Buyer must complete and return the enclosed warranty card within 15 days of purchase, or register online.

This warranty covers defect in materials or workmanship that occurs in normal use. Within warranty period PJB or its local distributor will repair or replace the defect unit free of labor and parts charge. It is the buyer’s responsibility to use the unit strictly according to instructions written in the owner’s manual.

This warranty is not transferable; it is provided to original owner only.

Damage/defects caused by the following conditions are not covered by this warranty:
  • Improper handling, neglect or failure to operate the unit in compliance with the instructions given in user manual;
  • Connection or operation in any way that does not comply with the technical or safely regulations applicable in the country where the product is used;
  • Repairs or modifications by anyone other than authorized PJB service agent;
  • Speakers are not covered for damages caused by incorrect connection, or when powered beyond the limit described in the user manual.
  • Manufacturing defects are typically detected during early usage.

    In all warranty issues your first line of communication should be to the retailer you purchased from, even if you have purchased product from an online source.

    When a local distributor is available, customer who prefers to purchase across country online may be required to pay shipping charges to retailer in order to obtain service.

    Warranty term/condition might be different depending on the country you are in. Please contact your local distributor for details.

    Further questions, please contact PJB by email, or call (855) 227-7510.
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1 Review

  • 4

    Great for certain applications

    Posted by Jonathan Dreyer on Jun 19th 2024

    I bought this for two reasons: First, to use as a monitor because I can't usually hear the highs when standing in front of my cab, and second, as a practice amp with my EUB when traveling. It works very well for those situations. It might also work when you need just a little help in a very small venue with a small, quiet band, but I haven't tried that. The main issue of course is that it's completely missing most of the lowest octave of the bass, but for monitoring and practicing, those aren't big issues. It's also not very loud, even at its loudest. Why did I not get the even smaller PJB Ear Box instead? One reason is that it's just a speaker, not an amp, so it wouldn't work as a practice amp. The other is because the Ear Box is not really that portable because you seem to really need a mic stand for it. With the NanoBass, I have rigged up a little stand that angles it up at 45° that I just sit atop my amp+cab. Maybe that would work with an Ear Box but they say you have to get really close to it.

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