… About EL34 and similar pentodes, of course, used in valves amplifiers.
EL34EH
The new Electro-Harmonix EL34EH tube is extremely musical, with a sound that is rich, smooth, and highly detailed without being edgy. It is the perfect EL34 for vintage equipment and a sure way to improve the performance of modern equipment. According to the technical journal, Vacuum Tube Valley, the “…new EL34-EH tube comes very close to the sonics of a Mullard EL34…”. They go on to say, “The Electro-Harmonix tube is balanced throughout the entire music spectrum. Bass goes deep and is tight, mids are sweet and well defined and highs are detailed and extended”.
JJ EL34L
The sound is well balanced with tight bass response and great mids. As with many of the Eastern European tubes, mechanical noise is an issue if used in high power combo style amps, but in a stereo system these provide a good tonal balance and service life.
Tung-Sol EL34-B
From the manufacturer: “The Tungsol EL34-B is a higher impedance EL34 tube design with increased touch responsiveness and a unique clipping characteristic with a hint of the 6L6 sound”. The Tung-Sol name and trademark have been acquired by the New Sensor Corporation. This new production Tungsol tube is manufactured at their Xpo-Pul factory (also known as Reflektor) in Saratov, Russia. New Sensor is an American corporation and since taking ownership of this factory has been steadily improving the quality of current production tubes.
Winged “C” (SED) EL34
The SED EL34 / 6CA7 tube is a power pentode intended for ultra linear audio frequency power amplification service. in either pentode or triode connection and single or push-pull/parallel tube applications. The SED EL34 plate is made from a laminated material that improves heat transfer. It has superior performance under overload conditions (often seen with guitar amplifiers). 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 it contributes to the overall performance. Lots of clean headroom from this tube with a smooth transition into breakup.
Electro Harmonix 6CA7EH
Designed to the exacting specifications of the Philips 6CA7 tube, this classic tetrode returns to life in a big bottle design. The 6CA7-EH is built to withstand today’s high-gain amps while still retaining the detailed tone and component integrity of the original. A direct replacement, with military reliability, for any EL34.
Gold Lion KT77
After extensive research and engineering, New Sensor Corp. has reissued the famed Genalex Gold Lion KT77. This tube has been recreated down to the finest detail for exceptional performance and sound quality. For audiophiles, the Genalex/Gold Lion KT77 tubes have full, yet tight and dynamic lows. They have great clarity in the mid-range as well, and extended highs. Many audiophiles that have previously enjoyed the Winged “C”/SED EL34 tubes have reported that these KT77 tubes are noticeably better.