2/22/08

JJ E34L / EL34

JJ is the new name for the Teslovak (Tesla) tube company. A good general purpose EL34. As previously mentioned, the sound is well balanced with tight bass response and great mids. Early on we had issues with mechanical noise however later stock has been much improved and noise is no longer a worry.


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Winged "C" / SED

If you want one EL34 tube that will do anything the Winged "C"/SED is money well spent. There is ample bass response but it is firm and controlled. The mids are smooth and the top end shimmers. Nice swirling harmonic content. The construction of the tube is outstanding and I feel it contributes to the overall performance. Lots of clean headroom from this tube with a smooth transition into breakup. Probably great in home audio applications, but if you want raunch at lower volume levels keep reading.


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Svetlana EL34

The Svetlana is the perfect tube for classic rock. The midrange is very pronounced and the high end is smooth. The bottom end response is not the best, but in a guitar amp it becomes a moot point. In the test amp the mids just rip through the mix. No guitar player is going to get lost in the mix using these bottles. These tubes deliver incredible crunch making them perfect for that ZZ Top, old EVH sound. Seven string down-strokers may not be as pleased because they don't have that crushing deep bottom end. (Note: the amp used for this review was done in a 100 watt Marshall JMP)


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Sovtek EL34WXT

Sovtek has come a long way with this tube since the EL34G. Construction has been improved greatly reducing mechanical noise. Very good sound but not in the same range as the Svetlana. It seems as if the frequency response has been shifted toward the midrange band. Harmonics are rich and fairly balanced but the high end can get a bit bright. Great in a darker sounding amplifier.



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Shuguang EL34-B

For many years no one would have believed that Chinese tube factories could turn out work of this quality. The construction of this tube is first class, with a well-supported plate structure that rests in a large straight bottle that tapers to a well finished brown base. These tubes represent a very solid piece of construction with almost no mechanical noise and an overall feeling of quality.The sound is loud and clear with a very nice sonic range. Not excessive in tops, mids, or bass, they are accurately described as well balanced. The sample tested had no audible microphonics and an average background noise level. Harmonic content was rich, lending that pleasant "swirl" and sustain that guitar players crave.


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JJ KT77

The KT77 has been gone for many years and original NOS pieces are rare and expensive. JJ electronics has revived the design and released their own version. To my ears it sounds a lot like a 6L6 but has the heater current, max plate voltage and output rating of an EL34. The JJ KT77 has published specs that are identical to the original Genalex specs. The base has pin 1 included but there is no connection to any internal element. The sound is somewhere between an EL34 and a 6L6. Overall a nice balance of tone in bass, midrange and treble. The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34. Unlike an EL34 this tube can be used in place of a 6L6 in Fender amps with minimal modifications. Vintage Fender amps usually use pins 1 and 6 as tie-off points for input grids and screen grids, mounting resistors on the socket. A standard EL34 can’t be plugged in because the input grid would be shorted to the suppressor grid via pin one. The KT77 avoids this. The only caveats are to ensure that your power transformer can supply an extra 500ma of heater current per tube and that the range of bias voltage adjustment is correct. If you have a Marshall amp and find EL34’s too compressed and 6550’s too crunchy the JJ KT77 may be just the ticket.

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Electro Harmonix 6CA7-EH

At last something to replace the hole left since the EI 6CA7 went out of stock. These tubes sound every bit as good as the old EI tubes and are probably my favorite tubes for Hiwatt guitar amplifiers. It’s like they were made for each other. These tubes are like EL34’s on steroids. They handle high voltage and current without problems. As mentioned, there is nothing like a Hiwatt head powered by 6CA7 tubes and driving a 4x12 cab loaded with Fane speakers. This is classic rock tone at its finest. It’s the sound of Pete Townsend and The Who. The 6CA7 has more headroom than an EL34 and by the time you get it really crunchy sounding your pants are flapping in the breeze. Just the right amount of compression for great thick rock tone. Biasing levels can be dialed in from warm to hot without causing significant tonal changes. The EH is well constructed and should not pose any noise problems. If using these tubes in more reasonable systems the EH 6CA7 is capable of some really nice clean tones thanks to that extra headroom. If you want early Van Halen, these are not the tubes for you. If you want something loud and proud, you want to put the EH 6CA7 in your amp.

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EL34 Tube Type Review

Review Notes
Tube reviews written by John Templeton.


It’s not easy evaluating something as subjective as sound. We each have our own personal taste in music and the way it sounds. I have attempted to add some objectivity by defining some aspects of tube performance that affect any listener, regardless of application, budget or musical taste. The EL34 is a very popular tube and is used in equipment that creates as well as reproduces music. This testing was done using tube guitar amplifiers. With this in mind, consideration has been given to construction quality and mechanical noise. These factors are important to musicians but may not be an issue when a tube is used in the home or studio.


Test Amps:

1973 Marshall Super Lead model 1959 This amp is completely stock using NOS pre-amp tubes. The sound was reproduced through a 1971 Marshal cabinet with 4 Celestion G12M "greenback" speakers.


Class A Combo Designed and built by Bernard Raunig. This is a true single ended class A amplifier, using a 5Y3 rectifier and a single 5691 pre-amp tube. With a volume and single tone control this amp really lets you hear the tonal differences between the tubes.



EL34 comparison at a glance
Rated 0 - 5 where 0 is Poor and 5 is Excellent
Rows in gray are tubes used for reference

Electro Harmonix 6CA7-EH

JJ KT77

Shuguang EL34-B

Sovtek EL34WXT

Svetlana EL34

Winged "C" / SED

JJ E34L / EL34

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