This tube has been a personal favorite of mine so the review is not entirely unbiased. With the JJ you seem to get a compromise between tone and reliability. Nice mids, sparkling highs and solid bottom end characterize this tube. From a construction standpoint I think JJ has hit the mark. As with any EL84 they can be prone to mechanical noise in combo amps. However, they seem to take the heat and vibration in stride without any negative tonal effects. In the AC30 the JJ tubes really delivered the VOX chime with lots of swirl and shimmery harmonic content. In the little Pro Junior just crank it up and you get a great, nasty, overdriven sound. That’s not bad, it’s good. When pushed hard into the land of the square wave they remind me a lot of a good 6V6. If you have tried the OEM Sovtek’s that shipped in your amp it’s worth your time to try a set of JJ EL84’s. Many convert and never go back. In cathode biased amps you can generally plug and play for that hot creamy “woman tone” that so many desire.
Information from thetubestore.com
2/21/08
Tesla / JJ EL84
TAD EL84-STR
The STR designation tells us that this was a Special Tube Request by the Tube Amp Doctor. In all honesty it looks and sounds like a pretty radical take on the EL84. The dimensions of this tube deserve your attention. Most tubes made in the U.S., England and Germany were built to a standard size. I often compare the new breed of EL84’s to the 1964 G.E. Essential Tube Characteristics Handbook. The TAD EL84STR is about a quarter inch shorter than any EL84 on the market and falls below the minimum GE spec of 2.344 inches. You may have to modify or adjust spring and clip type retainers for the shorter bottle. These are beefy bottles as well, with a measured maximum width of .874 inches. The GE specification is a maximum value of.875 inches. The TAD EL84STR also has the largest plate structure of any EL84 you can buy. I won’t give any more specs. Just trust me on this one, it’s enormous! There is very little clearance between the plate and the bottle and they get hot! This tube has the deepest bass, the highest highs and strident mids. In short, they sound a lot like a premium 6V6. No smooth creamy distortion here but tons of rock and roll crunch. If your bored with your normal EL84 tone these are definitely tubes to consider. Not recommended for some VOX amps as well as some smaller Mesa Boogie amps due to size issues.
Information from thetubestore.com
Russian EL84M
Some people will swear that the “M” stands for military but I’m not convinced. They look pretty much the same on the outside as normal Sovtek ‘84’s but there has to be something extra happening. The M’s seem less prone to mechanical noise and will do much better at surviving the VOX torture test. I loaded up the AC30 with a quad of EL84M’s and found that they could be run for a couple of hours without overheating. The Heat/Cool cycle still has some affect on life but the 84M lasted longer in this environment than the standard fare. A good choice if you have a cathode biased amp or like your tubes biased to more than 70% of idle dissipation.You do pay a sonic and financial price for the EL84M. They are more expensive than the standard EL84 but will last longer. Sonically they are a bit of a different animal. People refer to them as sounding stiffer or more strident with more headroom and may not like the breakup characteristics when pushed. It is really a personal judgement call. If standard EL84’s have been a problem due to heat or noise and you find they don’t last as long as you would like, try the EL84M and see what you think of the tone. In my opinion they are worth the extra money for reliability and the tone is still classic EL84.
Information from thetubestore.com
Sovtek EL84
- The Sovtek EL84 has been a staple for Fender, Boogie, Crate, Peavey and other manufacturers of tube amps using the ’84. This tube really is a good value. It is predictable, reliable and affordable. You can get good EL84 tone at a reasonable price. The Sovtek EL84 has been around a long time, and it has shown continuous improvement over the years. Using a matched set of properly biased tubes will yield a clear smooth sound that is fairly warm and transitions into a smooth breakup with that singing tone that EL84’s are known for. In cathode biased amps like the VOX they get a premium workout and will suffer some effects from heating and cooling. Being prone to mechanical noise in a combo amp, the EL84 is not recommended for amps with poor air circulation. The heating/cooling cycle inside an AC30 easy-bake oven seems to loosen up the mechanical structures within the tube causing them to become very noisy (mechanically) with time. This is true of any amp that uses an EL84 in a poorly ventilated chassis/cabinet arrangement, so if this is your rig, go for the JJ or Russian EL84M.In the Fender Blues Junior the tubes can really put out respectable volume and great tone for all types of music. The highs are not harsh, the mids are warm and the bottom end is not lacking. If you want to really scream try a Pro Junior with full volume. Very crunchy yet smooth with great singing sustain. I personally like my tubes biased at 60% or 70% of static dissipation and the Sovtek EL84 performed well in this range.
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Electro Harmonix EL84-EH Review
For most applications this is a good bet. The sound of these tubes is very smooth when biased correctly. Tonally, it’s hard to go wrong. They are pleasant to listen to and have the creamy overdrive most people look for in an EL84. They have a nice chime but it’s not overbearing. It looks a lot like the standard Sovtek but a closer inspection will reveal differences. The plate looks a bit more polished with a different coating and internally they feature precisely wrapped grid wires with a bright metal shine. The only problem with this tube is that like the Sovtek and TAD product, they are tubby. The fattest one I measured was .886 inches thick against the G.E. maximum width spec of .875 inches. For most purchasers this will not be an issue. If you have an amp that requires the tube to pass through a hole in the chassis before the pins seat in the socket you should measure the diameter of that hole. If you’re still unsure, the JJ EL84 is the closest in dimensional specs to NOS measurements and the G.E. standards for the 6BQ5.
Information from thetubestore.com
EL84 Tube Type Review
Review Notes
Tube reviews written by John Templeton.
For these tests I was lucky enough to secure the loan of some classic amps and some modern gear as well. The test amps used in this round included:1961 VOX AC30 – No top boostMid 60’s VOX AC10 – TwinFender Blues JuniorFender Pro JuniorAll of these amps are combos and put maximum stress on power tubes when it comes to physical vibration and heat build up. The VOX AC30 should have a health warning for tubes since I have yet to encounter a harsher environment to operate in. I know that a lot of Boogie fans would like to hear how these tubes fared in the .22 Caliber and other smaller Boogies. Trust me, you can’t handle the truth. On with the show.There has not been a lot of space devoted to this tube in the past. The main reason was that current production provided a limited selection. Let’s forget about New Old Stock for the time being. They’re out there, they are expensive and sometimes represent the dregs of production.
The Complete Reviews
Electro Harmonix EL84-EH
Sovtek EL84
Russian EL84M
TAD EL84-STR
Tesla / JJ EL84
Information from thetubestore.com
