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KT77 vs. KT88 Tube Shoot Out! (Do We Have a Clear WINNER?)

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Are you fond of guitars, amplifiers, and their components? Do you want to know more about what element you are using for each of your audio instruments? Among these components, an essential part is the vacuum tube.

They allow the flow of current through the wires, enabling the instrument to perform maximally.

A vacuum tube is also an electron tube, tube, or just a valve. It mainly controls the current flow inside a high vacuum between electrodes. Vacuum tubes were initially used in model radios, amplifiers, and television sets.

The cathode heats up so that it emits electrons, allowing sufficient current to pass through. Among the most popular vacuum tubes are the KT 77 and KT 88.

If you are planning to invest in good guitars and are confused about whether you should go for KT 77 vs. KT 88, or if you want to know more about KT 66 vs. KT 77 vs. KT 88, this guide is for you.

KT 77- An Overall Review

Genalex Gold Lion KT77, Matched Quad (4 tubes)
  • Tight, dynamic bass, with a great mid-range and extended highs
  • Matched for both plate current and transconductance
  • Matched quad (4 tubes)

The KT 77 is often used interchangeably with EL 34. The latter offers midrange frequencies and also helps produce a classic Marshall tone, while the KT 77 tube will result in a deeper and more open frequency with a clean, high-end.

The tweeter used in the KT 77 came from the famous Jensen G-610 Triaxial 15-inches driver, requiring a significant number of negotiations with Jensen.

The Klipschorn acquired the three-way horns not until 1952 since a two-way 12 kHz frequency was sufficient during that time.

The KT 77 is a newer version of EL 34. It has more outstanding durability and reliability and is sonically beautiful. It provides a smooth and incredible bass, airy highs, a fantastic 3D presence, and a great frequency.

The KT 77 tube is an absolute treat for the audiophiles since it creates as well as reproduces music in the loveliest manner when combined with an amplifier or guitar.

It is a drop replacement of EL 34 or 6CA7. The sound, however, is not typical of these models but a hybrid. It offers a more pleasant sound than you would expect of an EL 34, but the top-end is bright and open.

The overall look of the KT 77 tube is similar to that of 6CA7 or 6L6, but the bias adjustment is better. It has a full but still a somewhat tight, dynamic low.

The excellent clarity in the midrange is quite noticeable, along with the extended highs. Several users of the Winged “C”/ SED EL 34 tubes have shared that the KT 77 tubes are better.

KT 88- An Overall Review

Genalex Gold Lion KT88 Power Vacuum Tube, Platinum Matched Quad, Pack of 4
  • Gold plated grid wire, carbonized screen grids, and a tri-alloy clad plate structure for exceptional performance and sound quality.
  • “King of Power Tubes”, became the heart and soul of such classics as the Dynaco Mark III, McIntosh MC275, and Marshall Major
  • Platinum quad (4 tubes), computer-matched by manufacturer on proprietary equipment
  • 6550 equivalent

The KT 88 tubes are also excellent options for vacuum tubes. It is considered to be among the best-sounding power tubes, especially for hi-fi audio amplifiers.

The KT 88 tubes generally have a midrange comparable to the smaller EL 34 tube. The extremes, however, are low and high and reach further.

KT 88 tubes were invented by Marconi Osram Vale Co. and quickly gained widespread popularity. They were tough competition for the USA-made 6550 tube.

Numerous companies, including Dynaco, Mclntosh, Leak, and Harmon Kardon, offered premium-quality amps that perform similar to the KT 88 tubes. However, they remained at the top.

Currently, several reputable audio tube amp companies rely on the KT 88 tubes or its variants, such as the KT 90 and KT 120, for their tube amplifiers production.

The high-end companies, including Mclntosh, Cary Audio, and Jolida, all sell vacuum tubes incorporating the KT 88 tubes.

Klipsch KT 66

The KT 66 is a vacuum tube introduced by Marconi Osram Valve Co. Ltd. In 1937 in England. It is sold as a power amplifier for various audio frequencies and a driver for radio frequencies.

It produces low distortion and is frequently used in the guitar and other famous audio amps due to its incredible qualities. 

It does not saturate easily and showcases a clear and solid low end. On the other end, the highs are very smooth. Similar to the EL 34 vacuum tube, it forms a great crunch when it is overdriven.

Although the KT 66 can substitute for the 6L6 tubes, they are not entirely interchangeable.

KT 66 vs. KT 77 vs. KT 88

KT 66 draws 50% more current than the 6L6 tubes, falling at a level of about 1.3 A. The 6L6 amplifiers are also not equipped with powerful transformers which can handle high current.

Therefore, the KT 66 may be a better option if your area has a good supply. However, the 6L6 will function better on low current. 

The KT 66 is quite like in 6L6 in several features, while the KT 77 is close to EL 34 but still quite different. KT 88 is often compared with 6550, but again, it has some distinctive features.

Buying Guide-Guitar Amp Tubes

Now that we fully understand what the KT 77 and KT 88 and their importance, let’s talk about how to buy the right guitar amp tube. 

Why are guitar amp tubes so important? What do they really do for the guitar? Is a good-quality essential for the instrument to produce the right sound and other characteristics? The answer is yes!

The correct guitar amp tube can completely change the game for your guitar. A guitar amp tube conditions and shapes the overall tone of the incoming signal, ensuring you get the exact style you are aiming for.

However, it is crucial to mention here that you can’t just buy any guitar amp tube. Finding the right amp tube that works perfectly with your guitar is what will set your tunes and tones apart from others.

The ideal guitar amp tube should effectively control the amplifier’s output. Combined with the preamp tubes, this power creates the guitar’s distinctive tone.

Now, let’s talk about how you can find the right guitar amp tube. What are the things that you should consider when getting something this important for your beloved instrument? Take a look at the buying guide below to find out:

Unfortunately, the right amp tube will not just come to you; you will have to test and try several before finding the one you need. Ideally, bring your guitar to the amp store, put the amp tube in, and then play.

Ask for help from the sales representative and buy the amp only if you like it. To make the right investment, ensure that your chosen preamp tube checks all the boxes. It should have the following:

Convenient Size

If you are a beginner, you do not necessarily need an expensive guitar amp tube initially. Get a small practice amp tube and see how you work with it.

The small size also works exceptionally well for the professionals as they may need to travel for various reasons, such as for band practice, concert, or tour.

Controls and jacks

One of the essential factors to consider when buying tube amps is the controls and jacks. Some controls are pretty universal for amplifiers, so it is best that you understand them thoroughly so you can buy them regardless of where you are.

Knowing how to control the functionality of an amplifier is imperative. For instance, it is good to understand the amount of clean volume you need, what are the AUX inputs, the parametric EQ, and so on.

1. Gain

Gain is perhaps the most important control for any amplifier. The gain knob is mainly responsible for the guitar’s tone alteration. But it does not significantly contribute to the amp’s volume, contrary to popular belief.

The gain is simply a mathematical sum- it combines the volume of the input and output signal. So basically, if you get the wrong amplifier, you will end up with a channel making sounds louder than intended.

2. Volume

Several artists confuse gain with volume; however, that is not the case. The volume knob is what the name suggests- it controls the amplifier’s output, which is volume. This control does not impact the tonality much.

3. OD

OD, short for overdrive, is another control that is mostly present as a small button. It has numerous names, but the most popular ones include OD and distortion. The distortion of the signal depends on this control.

The greater the OD, the larger the distortion. The role of OD is most significant in rock and metal, where it is needed to distort the signal, so a loud, wild, and crunchy tone is produced. However, not all amps carry this feature.

4. Treble and Bass

Two other vital controls are treble and bass. They are shelf equalizers that considerably affect the guitar’s amp sound.

When the bass knob is turned up, it produces a more profound and thicker sound (lower frequencies are amplified), whereas turning up the treble knob leads to a clear, sharp, and detailed note (higher frequencies amplified).

Some guitar amps come with hi-mids, low-mids, and other options, representing the various parts of a usual equalization spectrum.

5. FX

Not all amps come with the FX feature. However, some may have one FX knob, while others have more than 10. The effect is mainly dependent on the product.

6. Cable Jacks

The input and output cable jacks highly depend on the amp you are using. Most amplifiers feature the input jack, where the guitar microphone is plugged in.

There may be other auxiliary inputs for headphone jacks, ramping, or a foot-switch pedal.

Some may also come with a ‘line out’ jack, which allows the user to send a signal from the amplifier to another instrument or software, like the PA system.

Or, it may send the signal back to the audio interface if you want to record using a microphone.

Popular Guitar Amplifiers

The most popular preamp tubes include the following:

  • Acoustics – Clean guitars: Electro Harmonics 12AY7, GE 5751, Fender 12AT7
  • Grunge – Classic metal: TT 12AX7, Tung Sol 12AX67, JJ ECC83S
  • Blues – Classic rock: JJ 12AX7, TTE 83CC, Mesa Boogie 12AX7
  • Thrash MetalExtreme metal: SOVTEK 12AX7LPS, JJ ECC83S, TT 12AX7

Some of the vintage preamp tubes are the following:

  • GE 12AX7WA: dark, sharp sound.
  • MULLARD 12AX7/ECC83 modern/old logo: high gain, heightened mid frequencies, ideal for British amps. 
  • BRIMAR 12AX7: Pretty similar to Mullard. 
  • TELEFUNKEN ECC83: high definition, bright sound, pricier, less grainy than a Mullard
  • GE JAN 5751: 30% lower gain than a 12AX7 produces a bright sound.
  • RCA 12AX7A: high gain, American fat sound, ideal for crunchy sounds (metal and rock). 
  • TUNGSRAM ECC83: Balanced sound, enhanced mid-lows, high definition, high headroom
  • RCA 7025: lower gain, suitable for clean tones.

Famous power tubes include the following:

  • 6L6: JJ 6L6 and TT KT 66 for a sound ranging from blues to hard rock, TT 6L6, Tung-Sol 6L6, Sovtek 6L6 WXT+ for heavier tones up to extreme metal, and SED 6L6 for low bass and tunings. 
  • KT88 / 6550: JJ KT 88 is suitable for every genre. Electro Harmonix KT88 are suggested for Bass amps, while SED KT 88 are rich in lower frequencies.
  • EL 84: JJ EL 84 for a Standard sound, Sovtek / Electro Harmonix for an overall tone, JJ EL 844 For a tight, low-power sound.
  • EL 34: JJ EL 34, Electro Harmonix EL 34 for sounds ranging from blues to hard rock, TT EL 34 and Tung-Sol EL 34 for Heavy Metal, SED EL 34 for dropped tuning and bass.

Frequently Asked Questions

1. Which one is better-KT 77 or KT 88?

KT 77 is an interchangeable model with EL 34, while the KT 88 is an entirely different model.

2. Which vacuum tube is the best- KT 66 vs. KT 77 vs. KT 88?

The KT 77 tube will result in a deeper and more open frequency with a clean, high-end. The KT 88 tubes are often used to make more vacuum tubes due to their great sound reproduction.

The KT 66 tube is known to have a 3D sound, which is pleasant and very clear. The KT 88, however, is considered to be at the top.

3. Are KT 77 and KT 88 interchangeable?

The KT 77 and KT 88 have the same pinout. Therefore, they are interchangeable in some circuits.

4. How long do KT 88 tubes last?

The KT 88 tubes perform considerably well for 2500 hours or more. They may last you longer f the amplifier has a conservative design.

In contrast, the small signal tubes, such as 12 AU7, 12 AX7, and 6922, may go on for over 10,000 hours.

5. Are 6550 and KT 88 the same?

The model 6550 is a beam tetrode that is quite similar to KT 88 and KT 90, and often interchangeable. They were introduced in 1964 by Tung-Sol.