Vacuum Tubes for Audio, Music and Radio from BOI AudioWorks

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Best EL34

What is the best EL34?

Mulalrd EL34 Re-Issue from BOI AudioWorks

We get asked that a lot. And the answer is, well, it depends. It depends on many things, but most importantly on your preference and taste.

Since everyone's taste is different, we have put together this information in the hopes that this will help you make an informed decision. If you need to compare tubes side by side, please take a look at the Quick Lookup box in EL34 category.

EL34 and Variants

There are several variants of EL34 that has different sound characteristics.

EL34 - The Original

EL34 was developed by Philips back in mid 1950s. Due to its high power handling and compact size, EL34 became very popular for audio amplifiers.

KT77 and 6CA7

In order to compete with EL34, 6CA7 and KT77 were introduced by American and English companies back in 1950s. 6CA7 and KT77 are direct drop-in replacements for EL34.

In fact in US, EL34 and 6CA7 were often labeled as EL34/6CA7. So it is true that at one point in time, EL34 and 6CA7 were literally the same thing. This has created fair amount of confusion in the old days as to whether 6CA7 and EL34 are different tubes.

The fact is, due to patents original 6CA7 and KT77 were made with different internals than EL34 (pentode vs beam tetrode). Consequently, current production 6CA7 and KT77 that are true to their origins sound different than EL34. In some cases, the difference may be preferable than EL34.

Because of these differences, EL34 amp owners today have a wide range of sonic choices. There has never been a better time to own and enjoy a tube amp featuring EL34 output tubes.


EL34 in audio amps produce signature velvet smooth mids. EL34 excels at music featuring horns and female vocals. In guitar amps, EL34 produces smooth highs and pronounced but pleasant mids that is well suited for classic rock sound.

We stock wide selection of EL34 tubes that best suits your favorite music style and budget.

SED EL34-WC Vacuum Tube from BOI AudioWorks
  • Best for Upgrading
  • If your stock EL34 tubes are sounding flat, upgrading to Mullard EL34, Svetlana EL34-SV, JJ E34L or Tung-Sol EL34B can make a considerable difference.

    These tubes all do signature EL34 sound very well. In audio amps, these tubes produce smooth velvet textured mids. In guitar amps, these tubes have that mid that comes through, with smooth transition into break up with master volume turned up. These tubes are great for upgrading the stock EL34 in your amp.

  • Best Value
  • Electro-Harmonix EL34EH and Chinese EL34B are often installed as the original tubes by amp manufacturers. They provide solid performance at great prices. Replacing worn out EL34 tubes with OEM grade tubes is often all that is needed to bring back your amp to life.


KT77 is a direct replacement for EL34, but uses different construction (KT stands for Kink-less Tetrode).

KT77 was specifically designed for audio reproduction, and in audio amps, KT77 has less pronounced mids, but has clearer highs and fuller bass. This makes KT77 produce well balanced sonic without the unpleasant sizzle and flabby thumps.

Until recently, KT77 was all but lost in vacuum tube history as an esoteric but supereme audio tube. Today, modern tube manufacturers are producing KT77 with faithfully reproduced design and sonics.

  • Genalex Gold Lion KT77
  • As with all Genalex Gold Lion tubes, Gold Lion KT77 is built to the highest standards, with meticulous precision that stands above all other tubes being produced today.

    Gold Lion KT77 is a classic KT77 in that it smoothly balances out the lows and the highs, while adding the dynamics reminiscent of more powerful tubes like 6550. It manages both classic and contemporary materials very well. A Gold Lion KT77 can literally transform your EL34 amp and your music.

  • JJ KT77
  • JJ KT77 Vacuum Tube from BOI AudioWorks

    JJ KT77 provides good bottom extension, punchy dynamics and pleasant sizzle. Sound imaging is quite good.

    To date, we have received more positive feedbacks from our customers about this tube than any other tubes we carry. If you are wanting to hear what KT77 offers without paying the premium, JJ KT77 is an excellent choice.

In a guitar amp, KT77 provides good solid bottom end. It sounds well balanced and noticeably clearer than other EL34's at low volume as well. This makes it a good choice for daily or practice use. If you are looking to attain different tone in your guitar amp, Gold Lion KT77 and JJ KT77 are definitely worth a look.


Electro-Harmonix 6CA7EH Tubes from BOI AudioWorks

Like KT77, 6CA7 is a direct drop-in replacement for EL34, but with different internals (beam tetrode) that gives it characters that resemble tubes with similar construction: 6L6 and 6550.

While EL34 was housed in a skinny glass bottle, 6CA7 came in a fat bottle which made it easier to spot even when they were marked as EL34. Current production 6CA7 tubes closely follows the original fat bottle American 6CA7 construction and tone.

In guitar amps, 6CA7 has fuller fatter tone than EL34 with more bottom end. It sounds heavier and darker than EL34, but nicely controlled with little mushiness. 6CA7 has more headroom which makes it harder to push, but once you go into overdrive, it takes on proper amount of aggressivness that makes it suitable for hard rock, but with less edge and bite than an EL34.

  • Electro-Harmonix 6CA7EH
  • 6CA7EH is a faithful reproduction of American fat bottle 6CA7. It is a mature design that has proven rugged and quite reliable over time. 6CA7EH sounds full and heavy, and clean tone comes through without clipping early. If you are looking for more defined bass from your EL34 amp, 6CA7EH is definitely worth a try.

  • JJ 6CA7
  • 6CA7 JJ is a new design that is completely different from their EL34 and E34L tubes. We have seen JJ EL34 listed as EL34/6CA7 at time which can be misleading, but 6CA7 JJ is a completely different new tube from their existing EL34 line.

    6CA7 JJ is a true beam tetrode design, and it sounds a lot more like 6L6 than an EL34. It has good amount of crunch and punch you expect from 6L6, but perhaps with little less sizzle at top. It is very much a great classic rock sounding tube.

by TubeTech
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