KT 66 vs. EL 34 Tube Shoot-Out: REALLY Any Difference?

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Let’s admit it – guitars are expensive! They require a good amount of money, and each component within matters as they all come together to give you the sound you desire.

There are thousands of options available in the guitar category. So, how do you really decide what to get?

You consider its components, machinery, and how they all work to produce a specific. Among the essential elements is guitar tube amps!

Guitar tube amps can make or break things for your guitar and the typical sound it produces.

Give it a nice, high-quality tube amp, such as kt66 and el34 hifi, and you will have excellent beats. However, if you mess up and plug in poor tube amps, you will do just the opposite. 

Deciding between various guitar tube amps is just as tough; EL34 vs. KT66, which is better?

Some users may also think, ‘are EL34 and KT66 interchangeable in JTM 45 clone?’ Or, how much difference is there between the KT66 vs. 6L6 Tubes in a JTM45?

Professional as well as beginner guitarists will have numerous questions running through their minds when shopping for something as crucial as guitar tube amps.

They should ideally compare both models’ qualities, including the KT 66 vs. EL 34 tonal differences.

Alternatively, passionate guitar players can also widen their options and take a look at all the features of other models, such as KT 88 vs. EL 34, KT 66 vs. 6l6, KT 77 vs. EL 34, KT 66 vs. KT 77, and KT 66 vs. KT 88

Indeed, deciding between all these options is not easy, especially if you are not as experienced as the regular buyers or if you are just starting out and learning the guitar basics.

However, the good news is that we have got your back! Don’t fret; we will break down things for you, making it easier to pick the right option. Take a look at all the models and their features and buy whatever suits your needs the best!

The Legendary Tonal Master- KT 66

KT 66, also known as the classic tonal master, is nothing less than extraordinary. It is a high-quality value ideal for amplifiers as well as guitars.

It is a creation of Marconi-Osram Valve Co. Ltd. (MOV), which was first introduced in Britain in 1937, and KT 66 has taken over the world since. 

Several modifications and improvements have been made to the KT 66 model as other instruments have gotten more modern. The KT 66 comes in an enveloped large curved glass bottled structure with a rounded brown base.

A lot of famous personalities have used this brilliant component, including SRV, who used KT 66 in his Fender Amps for a gigantic, splendid sound. 

The KT 66 has a full body, thick tone, and large headroom. The top-end is smooth but detailed.

It has a vintage British look, but different models can harbor different looks. Without pins, its height is approximately 115 mm (1.15 cm). 

While it has maintained its classic features, manufacturers have added some contemporary functions to allow the KT 66 to work better and be more compatible with newer machines and instruments.

Despite its new look, the KT 66 tube amp performs as well as the original. The KT 66 is popular for its efficient plate current, transconductance, and passing all the TAD Premium Selection tests.

Some experts also believe that it can be interchanged with any KT 66 model along with 5881 and 6L6GC amps. Known to have a cathode to heater voltage of ≤ 150 V, KT 66 has 500 V of D.C plate voltage. 

The KT Series

The KT series, including KT 66, was developed by the MO-Vale, also called the Genalex, keeping in mind Mullard’s invention of the pentode.

The fifth element of the suppressor grid was installed in the pentode to lower secondary emissions and maximize electrode transfer from the cathode to the plate. 

KT, short for Kinkless Tetrode, amp tube was made using beam forming plated to direct the electron flow while avoiding infringement on Mullard’s patent.

Pentodes keep the suppressor grid pinned to the socket. In pentodes and the KT series, the ratings are pretty much similar. 

In America, such tubes are referred to as beam tetrode, common examples including 6V6 and 6L6. While KT 66 and 6L6GC are related as kissin’ cousins, the EL 34 and KT 77 are also the same. Let’s take a closer look at the KT series:

1. Gold Lion KT 66

The KT 66 Gold Lion is a remarkable improvement from the traditional 6L6GC in terms of sound and instrument compatibility.

The KT 66 is known to create a big sound regardless of where it is being used, in a stereo receiver, guitar amp, or fat switch. 

Even at low to moderate volumes, KT 66 will give you large sounds across the guitar spectrum. With little compression and an articulate design, it gives an excellent response to dynamics.

As opposed to 6L6, which gives 900 mA current per tube range, the KT 66 tube amp sullies 1.3 amps current. Moreover, the latter has a minimal, reducing effect on the voltage. 

At higher volumes, the KT 66 Gold Lion is highly focused on the upper mids compared to other models, such as the Shuguang KT 66.

It produces a smooth, sustainable sound that highlights each note. The chords also compress reasonably well without losing individual note definitions or any mushiness. 

The Shuguang KT 66 tubes give out a compressed sound with some raw ends. While both KT 66 and Shuguang produce lively sounds, the former has better sound quality at low as well as high frequencies.

The Gold Lion KT 66 also has an impressive gold-screening bottle that fits easily into small amps, like the Marshall Bluesbreaker reissue. In plain words, the overall construction is reasonably impressive. 

2. JJ KT 66

The JJ KT 66 is another amp tube famous among professionals. It has a build similar to the GE 6550. The JJ KT 66 does not look like typical British tubes with its 6550 diameters and height.

The Russian and Chinese variants use two support sets for the plate. The thick glass combined with the heavy base is very effective, leaving small room for microphonics. 

JJ KT 66’s overall tone is quite balanced and revolves around the warm, thick midrange tones. It can also handle low voltages on its plates without biasing problems.

The JJ KT 66 can produce crystal clear sound with a juicy crunch when in overdrive. It is an excellent choice for the classic rock & roll genre. 

3. Shuguang KT 66

The Shuguang KT 66 is another functional tube amp. It is similar to the original KT 66 in several ways. It is pretty big in comparison with other guitar amps; therefore, please ensure there is sufficient space before installing it. 

The Shuguang KT 66 has specs like the original 25- watt models. It draws a greater current than the standard 900 mA, approximately 1300 mA. So, make sure your power transformer can easily supply enough.

These tubes make a bright, crystalline sound with a 75% dissipation rate. The Shuguang KT 66 offers a rolling thunder-like sound, but you can turn up the heat for a beefier sound. But please keep an eye on the power tranny!

The British Sound Master- EL 34

The EL 34 is a classic tube amp that is widely used in guitars and other instruments. It has a unique sound and is known for its smooth, creamy midrange tones, along with its large headroom.

The EL 34 is also popular as KT 77 and 6CA7. The EL 34 is a power pentode that comes with an international octal base. Philips introduced it in 1949, and it is now manufactured by Shuguang, JJ Electronic, Reflktor, and Svetlana.

All the upscale EL 34 tubes are tested and platinum-screened. Initially burned in, the EL 34 tubes are tested at real-world voltages for correct specifications. 

The EL 34 gained significant popularity as the British Sound tube amp. Most amps over 30 amps feature the EL 34. It has a high output wattage with large headroom. It can push around 50 watts in a typical AB class configuration. 

Known to have the classic Marshall tone, the EL 34 has multiple low-end crunch tones and a beefy midrange. A strong midrange and an aggressive sound are its salient features. 

The EL 34 Series

Let’s take a look at some of its types:

1. Electro Harmonix EL 34

If you are looking for clarity and a popping beat, the Electro Harmonix EL 34 is your best bet. It is sonically like the EL 34 but has a different design with a shorter and fatter body. Therefore, it is ideal for tight spaces.

2. Mullard EL 34

Another model is the classic Mullard EL 34. It is a modern recreation with more incredible warmth, a considerable amount of top-end extension, and plenty of detailing.

With a sweet midrange, it is known to have a tight bass and little harshness. The Mullard EL 34 is also suitable for stage sounds and balance.

3. Tung Sol EL 34

The Tung-Sol EL 34 is another model with reasonable warmth, great bass, and ample detailing.

The users often label it smooth, open, and a model with minimal harshness. The Tung-Sol EL 34 has received a lot of praise for its extended and tight bass.

4. Prima Luna EL 34

The Prima Luna EL 34 is made primarily by Shuguang. With a warm tone and excellent midrange presence, the Prima Luna EL 34 is dependable and boasts top and bottom ease. 

5. Gold Lion EL 34

The Gold Lion EL 34, also known as KT 77, is another remarkable model. It is a recreation of the great Genelex KT 77.

Showcasing outclass durability and great mids, the Gold Lion EL 34 has smooth, airy highs, plenty of 3D presence, and incredible bass. However, it does take some time to open up completely.

Therefore, give it about 100 hours or so to become completely functional. Undoubtedly, the Gold Lion EL 34 brings life to music, offering brilliant clarity, especially in the midranges.

Furthermore, it has good balance, detail to sound, and warmth. It is considered a better option over the NOS EL 34.

KT 66 VS. EL 34- The Key Differences

While both the KT 66 and EL 34 are great amp tubes that work excellently, they have some distinguishing features. The KT 66 will give you a clean sound, smoother with more bottom end.

Its sound is best demonstrated by the JTM 45/BB chiming cleans combo. On the other hand, the EL 34 gives off a brighter sound, hence its popularity for classic rock style. Hendrix and Page best showcase its style. 

Another difference is that the KT 66 is a tetrode, while the EL 34 is a pentode. Pin 1 of KT 66 may be internally connected, whereas the el 34\s pin connects to the suppressor grid. There is also variation in the ratings of both models. 

6CA7 vs. EL 34 vs. KT 66

The KT 66 is known to have a somewhat open and uncluttered sound with a harsher tone at the higher ends as compared to the 6CA7. In contrast, the latter is known to maintain great mids, big and tight bass, and smooth highs. 

While some users have reported reliability problems with the 6CA7, others suggest that these tubes work best when they are hot. The EL 34 is considered secondary to the 6CA7 amp tubes.

KT 66 vs. KT 77

While KT 66 is from the 6L6 family, KT 77 belongs to the EL 34 group. The KT 77 is a beam power electrode showcasing an octal base.

It is used widely in EL 34 amplifiers but has more power, bass, and headroom the a typical EL 34. Furthermore, the tones are also very detailed. 

The KT 66 is a beam tetrode with an octal base. It features a 25 W power and an aggressive sound with plenty of headroom. It is marketed as a driver for radio frequencies and a power amplifier for audio frequencies. 

Frequently Asked Questions

1. Are EL 34 and KT 66 interchangeable in JTM 45 clone?

EL 34 and KT 66 cannot be interchanged in the JTM 45 clone model unless you modify the amplifier.

Remember to change the screen resistors and ensure that your power transformer can handle the additional heat drawn by the EL 34 before switching them.

2. How much difference is there between the KT 66 vs. 6L6 Tubes in a JTM 45?

Several professionals and guitar amp enthusiasts who have used the KT 66 and 6L6 prefer the former.

This is because they believe the KT 66 is brighter with better tonal detailing. Moreover, it also offers a smoother top end with an excellent midrange. The overall sound is complex and rich.

3. Can you swap 6V6 for EL 34?

While it is possible, most users do not recommend switching the 6V6 for EL 34 because the former may not last as long.

A better choice is the KT 77 or 6CA7. Even when switching EL 34 for its other tubes, re-biasing is strongly recommended to prevent any unpleasant results, such as overload and imbalance.

4. Who used Marshall JTM 45?

The JTM 45 gained significant popularity as it was used by Eric Clapton, English rock and blues singer, guitarist, and songwriter. He is among the most successful and influential guitarists in the rock community.

The JTM 45 later became the basis for many Marshal models, notably the Marshall 1962 combo, also known as the Bluesbreaker.

5. Can KT 66 replace EL 34?

Replacing the KT 66 with the EL 34 is not a good idea since the former is a tetrode and the latter is a pentode.

The KT 66’s pin 1 is connected internally, and the EL 34 pin needs a connection with the suppressor grid to work efficiently.