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Fender Blues Jr III vs IV (The ULTIMATE Guitar Amp Shootout)

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When it comes to guitar amplifiers, there are many brands in the market. But not many brands are as good as Fender. 

Fender, over the years, has built a reputation as not just a top-class maker of guitars but also a maker of guitar accessories like amplifiers for both bass and electric guitars. Truth be told, Fender amps and cabinets are just plain awesome. 

Over the years, amps like the Blues Junior have achieved what we can rightly describe as cult-like followings. In this article, we will compare the legendary Fender Blues Junior iii with the iv version. 

It doesn’t matter if you already own either of these two or contemplating a purchase, this article is for you, regardless. 

Fender Blues Junior III

The Blues Junior is a tube guitar amplifier introduced in 1995 and belongs to the Fender Musical Instruments Corporation.

Fender’s Blues Junior amp was designed to imitate the tone of the company’s 1950s amp. 

Manufactured in Mexico, Fender launched the Fender Blues Junior III in 2010, updating their hot rod model amps series and adding various physical changes to the regular black tolex model.

The Fender Hot Rod line of guitar amplifiers has developed a cult-like reputation recently, with the adored Blues Junior being the most widely respected amp. It weighs only 30 pounds, but it packs a powerful punch.

The amp has long been a favorite among amp modders, and Fender has opted to include some of the most well-liked modifications in the amp right out of the box. Let’s explore Fender’s Junior III, a fantastic amplifier.

Fender Junior III specs:

  •  Fender Blues Junior III is a 15-watt tube amplifier.
  •  It has an Eminence 12-inch speaker.
  • Three 12AX7 tubes power the preamp, while two EL84 tubes power the amp. The Fender Blues Junior III  exists in a solid state.
  • It has a single-channel amplifier with settings for volume (gain), bass, midrange, treble,  master volume, reverb, and a FAT boost switch.
  • The amp weighs roughly 30 pounds and has the original Fender blackface grill cloth and black vinyl covers.

Design Manufacture

  • Cabinet Material: 7-Ply 3/4″ Birch/Maple Plywood
  • Amplifier Covering: Tweed Textured Vinyl
  • Handle: Moulded Rubber “Dog Bone” Style
  • Control Knobs: Chicken-Head Style Pointer – Tweed
  • Front Panel: Tweed
  • Footswitch: 1-Button (“Fat” ON/Off)
  • Dimensions: 12″D x 20″W x 18.5″H
  • Weight: 31lbs (14.06kg)

Fender Blues Junior IV

From the 1950s and 1960s, Fender has made some of the most famous electric guitars and amplifiers, like the tweed and blackface amps. 

In 1993, Fender released the Blues series amps, and in 2018, they released version IV of the Blues series amp. 

Being an upgrade from the previous Blue Junior III, the new preamp circuitry gives the sound more fullness, clarity, and definition. The built-in spring echo has been smoothed out, so you can get a rich, shimmering sound no matter how much reverb you use.

Below are some of this great amp’s specs:

Junior IV Specs:

  • Power: 15W (tube)
  • Three 12AX7 tubes (preamp) and two EL84 tubes (power amp).
  •  effects: Reverb
  • Single input
  • 1×12 Celestion A-Type Speaker
  • Controls: Fat Switch, Volume, Master, Middle, Bass, Treble, and Middle

Design Manufacture

  • Cabinet Material: 3/4″ Particle Board Amplifier Grille
  • Cover: Textured black vinyl grille Silver
  • handle; Molded plastic strap with nickel-plated ends 
  • Knobs: Ivory Chicken-Head Pointer
  • control panel; black 
  • Footswitch:  one-button 
  • Dimensions: 16 x 18 x 9.18 (40.6 x 45.72 x 23.31 cm)
  • Weight: 31.5 lbs. (14.3 kg)

The Fender Blue Junior IV is one of the most reliable gig amps on the market.

Fender Blues Junior III vs. IV Review

It’s no secret that Fender blues junior amps are among the most popular guitar amps. 

Additionally, Guitarists frequently inquire how the Fender Blues Junior III and Fender Blues Junior IV differ or are the same. So, let’s examine the two amplifiers more closely.

Technical Comparison   

A 10″ Celestion V10 speaker provides sound for Junior III’s 15 watts of power. It contains an 8-ohm speaker output, a single volume knob, and a three-way tone switch. The preamp and power tubes are both 12AX7s as well.

Alternatively, the Junior IV is a 20-watt amp with a 12-inch Celestion V12 speaker.

The output to the speaker is 8 ohms, and there are volume and tone controls. Two 12AX7 tubes are the preamp, while two 6L6s provide the power (EL84s).

The Junior IV’s EL84 power tubes and 12″ speaker give it a slightly different tonal quality, offering more tonal possibilities and a somewhat more powerful output than the Junior III. But both amps feature a clean, simplistic construction with classic Fender aesthetics. 

Frequency Response

The Fender Blues Junior III and IV have an almost similar frequency response. Both amps focus on mid-range frequencies to make the sound clearer and give a warm tone, with a small difference in the bass frequencies.

The III has a frequency response of 80 Hz, whereas the Fender Blues Junior IV has a response of 100 Hz, thus indicating that the Junior IV has the highest range of frequencies of the two. 


Many blues players, rockers, country pickers, or jazz guitarists rely greatly on the Fender Blues Junior amp because of its incredible tone and build.

Fender Blues Junior III is ideal for small shows and recording sessions, and it is also a popular option for use and practice at home.

Fender Blues Junior IV delivers a truly musical crunch. It will cover many various types of blues. The reverb makes your sound more three-dimensional and dumped when you ramp up the heat.


When using distortion, IV has a stronger, rounder, and clearer bass. This difference stands out at first when you listen and compare the two.


Since III’s reverb is a little washed out, IV reconfigured the reverb in a different area of the circuit, producing a more warm-sounding reverb.


IV has a more powerful and louder gain, and the IV sounds fuller when you side-by-side compare the two.


With the IV, using the pedals is even simpler, and it’s an effort to improve versatility.


IV employs the Celestion A-Type speaker, while III employs the “lightning bolt” speaker.

Fender Blues Junior III Pros and Cons

  • The Fender Blues Junior III is well-liked by guitarists and music fans. Many users commend the amp for its classic Fender sound, small size, and low price.
  • Some guitarists like its versatility since it can handle various musical styles and may be used for home practice and live performances.
  • On the other hand, some users have complained about its lack of functionality compared to more advanced amplifiers in the market.


  • Clear tones
  • Compact size and portability
  • Affordable price
  • Very dynamic
  • It can be used for practicing at home or playing live


  • Limited features compared to more advanced amplifiers
  • Weak reverb
  • Very loud
  • Lack of tone customization options.

Fender Blues Junior IV Pros and Cons

  • The Fender Blues Junior IV is a wonderful alternative for individuals looking for an amp with new features and enhancements over the previous model, Fender Blues Junior.
  • Customers have given it positive feedback, pointing out its classic Fender tone, compact size, and fair price cost. 
  • However, some customers have stated that more improved features may be required to warrant the higher price than its previous version. 


  • Classic Fender tone
  • Compact size
  • Easy portability
  • Improved reverb and onboard effects
  • Great amplifier sound


  • Expensive than the previous version
  • Limited tone customization options
  • Build quality issues (non-removable cord)
  • Improved features may not justify the higher price for some users.

An Overview of Fender Blues Junior IV

The loudness and richness of the tones produced by the Fender Blues Junior III will make you overlook its inadequacies in building quality and value for money. 

Carrying your gear to and from performances in a single trip is a practical benefit, as is using the full 15 watts of power to get the power amp valves sizzling.

The Blues Junior III’s simplicity is welcoming, with the FAT switch and speaker allowing future expansion options. It’s an amp that will allow you to develop as a player. It’s a skillfully made, great-sounding guitar amplifier from the industry’s top name.

An Overview of Fender Blues Junior IV

Fender’s devotion to quality extends to every product bearing the name and sporting the famous logo, from guitars to amps to accessories. Blues Junior was improved for its fourth version in 2018.

The Fender Blues Junior IV is a modified preamp for a tone and volume of sound that defies the amplifier’s modest size, an enhanced Celestion A-type 12″ speaker, smoother-sounding reverb, and trendy aesthetics are among the enhancements.

Although cheap, lightweight, compact, and easy to transport, others argue its price does not correspond to its worth. However, based on the benefits of using the above amplifier, one can be bold in recommending its use.

Frequently Asked Questions 

Why Is the Fender Blues Junior So Popular?

The Fender Blues Junior has become one of the most popular amps on the market, and for a good reason: it looks and sounds great, it’s not too expensive for what you get, can be used for different genres.

What Is the Difference Between Fender Blues Junior III and IV?

Fender Blues Junior III came out in the year 2010. The most recent one is Blues Junior IV, which came out in 2018.

It has a slightly deeper, rounder, and fuller tone than Blues Junior III. It can also handle a lot more gain. Not only can it make things sound more distorted, but it can also keep things from sounding too muddy.

How Many Watts is a Fender Blues Junior III?

The Blues Junior III is a well-known 15-watt favorite with a warm tone perfect for the go-anywhere guitarist who has to enter the stage or studio, with superb quality and adaptable features.


The Fender Blues Jr. IV is an upgrade over the III, which has a more classic tone. Comparing the two sounds, we can see that IV’s overall sound is unquestionably fuller.

The Fender community may be divided by certain basic changes, though. The Fender fans who appreciate the classic tone might still favor III, and the IV offers more bass for those who want it and want more playing style variety.

It is incredible how many sounds can be produced from these combos, given their limited reverb, middle, master volume, bass, and treble adjustment options. 

Guitarists can understand from the simplicity of their design that the most beautiful sounds do not demand the typical overkill of guitar amp functions. 

We sincerely hope that this article has aided in considering the differences between these amplifiers and which would suit you most.