If you own an EL34 amp, you know the magic it produces. EL34 tube produces smooth highs with pleasant mids in guitar amps. When pushed, the EL34 tube will produce the quintessential classic Marshall tone that's instantly recognizable.
In audio amps, the EL34 tube produces that signature velvet-smooth mids. EL34 excels at reproducing horns and female vocals with silky-smooth textures. A great-sounding EL34 amp is a joy to listen to all day.
Replacing EL34 Tube
Vacuum tubes wear out due to heat and high temperatures. Due to their narrower profile, EL34 tubes can run quite hot and tend to wear faster than other tubes in your amp. If you regularly use your amp, it's not uncommon for EL34 to lose its full potential after a year or two. Replacing with new EL34 tubes will bring back the luster and depth that your amp is fully capable of.
Our go-to EL34 tube for audio amp upgrades is Mullard EL34. It has good tight bass to balance out the beautiful mids. Mullard EL34 has velvet-like smoothness that has intricate textures. The top end has no hint of harshness, rounding out the warmth that you expect from an EL34 tube.
Mullard EL34 is no slouch in guitar amps, either. Mullard EL34 has sweet, crunchy mids and a bit more headroom. This results in clarity and better note separation when pushed. Mullard EL34 is less aggressive sounding than TungSol EL34B, making it a good choice for a wide range of music.
Tung-Sol EL34B would be our go-to for guitar amps. TungSol EL34B has smooth mids similar to Mullard EL34 but has a bit more bite when pushed. This gives TungSol EL34B a tad more aggressive edge. The highs are a bit more glassy, and there is a good amount of bass. While some may prefer the smoother tone of Mullard EL34, if you want a tone that you can turn up on demand, Tung-Sol EL34B is a good choice.
Electro-Harmonix EL34EH is a workhorse EL34 tube providing excellent value. EL34EH has less headroom and sounds a bit flatter than Mullard EL34 or TungSol EL34B, but EL34EH is certainly no slouch. Many amp manufacturers chose EL34EH as OEM for its reliability and consistent build. EL34EH is a solidly made tube that delivers EL34 sound at a good price point.
See EL34, 6CA7 KT77 catalog page for listings.
KT77 was all but lost in vacuum tube history as an esoteric but supreme audio tube. Tube manufacturers revived the KT77 along with the design and sonics of the classic KT77.
KT77 in Audio Amp
Gold Lion KT77 is the hands-down top choice for those who want to get that something extra out of their EL34 amps. Gold Lion KT77 maintains the mids of EL34 while filling out the lows and highs nicely.
If you are using EL34 amps with OEM EL34 tubes, Gold Lion KT77 is a big step up that can transform your amp.
KT77 in Guitar Amp
Gold Lion KT77 does very well in guitar applications. KT77 shares a beam pentode design found in tubes like 6L6 and 6550. Although KT77 is a drop-in replacement for EL34, the different design makes it a different tube altogether.
Consequently, the KT77 has more bottom-end and top-end sizzle than an EL34. Rather than the mid-focused tone of EL34, KT77 will provide a punch to go with the mids. KT77 doesn't sound as compressed as EL34 but breaks up nicely when pushed. The added bottom end even makes KT77 noticeably clear sounding at low volume.
Combining EL34 and 6L6 tone elements, KT77 tone will find more universal applications in different jenre of music. If you would like to get a different tone out of your EL34 amp, KT77 is an excellent tube try.
See EL34, 6CA7 KT77 catalog product listings.
6CA7 is often overlooked but is the favorite of many well-versed guitar players. 6CA7 tends to be heavier and darker sounding than EL34 tubes, and also offers a fair amount of sizzle.
6CA7 has more headroom. Once you go into overdrive, 6CA7 takes on aggressiveness, making it well suited for hard rock sound.
There are two 6CA7 tubes produced today, and we like both quite a bit.
Electro-Harmonix 6CA7EH is a reproduction of American fat bottle 6CA7. It is a mature design that has proven rugged and quite reliable over time.
JJ 6CA7 is a newer design, which has also proven to work quite well in guitar amp applications.
Related links: EL34, 6CA7, KT77 Difference?