How do the JJ's compare to other tubes?
I’m asked this question almost daily. The first thing I want to say is I am not an amp tech by trade. I am a player and I have been into tube amps for a very long time. Over the past few years since starting Eurotubes I have had the unique opportunity to listen to and play hundreds of different amps. Every amp that I retube in my studio is done on a one-on-one basis with the owner. If the amp is playable then we start by listening to the amp. Then I will check the plate current draw and plate voltage (with the exception of some of the more common EL84 fixed bias amps, I’ve checked enough of them to know were they are set). Then I check the power tubes on my Maxi-matcher and since I test, match and grade all my tubes this gives me the info I need to select tubes that will bias up properly for fixed bias amps.
For EL84 fixed bias amps and depending on the players style we will try two or three sets of power tubes in different heat ranges to hear what sounds best. For 6L6, EL34 and 6550 fixed bias amps I take the same approach but I check the bias for each set of tubes. I can usually get the bias real close by selecting different grades of tubes with the exception of the older Peavey 5150’s and ultras. These amps are biased so cold that even the hottest tubes won’t get them out of crossover distortion so unless we mod the bias to be adjustable, what you hear is what you get! For all adjustable bias amps we will listen to the amp at several different bias settings ( within the window of proper bias) to hear what sounds best.
I do not believe in the method that most people who compare tubes use, which is to set the tone controls to one place and leave them for the entire test. I disagree with this procedure because it does not allow you to get acquainted with the capabilities of the tubes. Some tubes get sweet when treble is dialed in and some get very piercing. It’s very important for tubes to be able to handle added lows, mids and highs without getting flabby, harsh or piercing otherwise you will turn your amp into a one trick pony.
I do keep a good well matched set of all the currently made tubes such as Svetlana’s, Sovteks, EH (sovteks), EI’s and a host of NOS power and pre-amp tubes such as RCA, Philips, GE, Sylvania, Telefunken, Mullard, Brimar, GEC and Amprex to name few for the purpose of comparing them to the JJ line of tubes.
The following are my opinions and the opinions of the vast majority of my customers. I will keep this to the most common power and pre-amp tubes.
Sovtek EL84: This tube has a very harsh mid and upper mid-range. If I had to describe the tone in one word I would call it "cardboard". They make your amp sound like a big Wheaties box. The low end is flabby and only gets worse as more lows are dialed in. The highs are piercing and brittle. These tubes are just flat and lifeless sounding without much harmonic content. When over driven they get real grainy and the break-up is quick and not smooth.
Sovtek EL84M: This tube has the same tonal characteristics as the standard Sovtek EL84 and is even more lifeless and less touch responsive.
Electro Harmonix EL84: These are sovtek tubes and all the above applies.
EI YUGO EL84: This is a pretty good sounding tube. The problem is finding good ones that are matched. They have nice harmonics and break-up pretty evenly. They don’t have a strong low end but dynamic response is good. The upper mid and highs are this tubes strong points. Nice detail even when distorted.
PHILIPS 6BQ5: Even though these are out of production NOS tubes are still fairly available at a decent price. These are nice, warm sounding tubes with good dynamics, nice harmonics. This tube has good definition but is hard to drive into distortion. A nice tube overall but I would use the EI before spending the money on these. They work pretty good for Hi-Fi.
JJ ELECTRONICS EL84: This tube has the deepest and tightest low end of any of the tubes reviewed here. The mids are thick and harmonically complex. The highs are sweet and smooth. These tubes are very punchy with a nice chime. When over driven they get nice and thick and do not loose their detail. The break-up is very smooth and linear and they are very responsive to touch.
Sovtek EL34WXT: This tube is an improvement over the EL34R which was a very lifeless tube on a par with the Chinese EL34. The WXT is still harsh in the mids and has a weak low end. The highs are grainy and piercing and when overdriven gets even more harsh and nasily.
Sovtek Mullard: This really bums me out that sovtek tubes are now being made and branded "Mullards". They are sovteks. Nuff said....
Electro Harmonix EL84: A sovtek tube, but a slight improvement over the EL34WXT with a shallow low end and grainy tone.
Svetlana EL34: These are now sovtek tubes and are about the same quality as the EH EL34 unless you have the older Svet's (the real ones)
Winged C EL34: In my opinion this is the best tube that Winged C (the original Svetlana) makes. It’s a little hot on the top end but it has nice harmonics. The low end is solid but not real deep. This tube has good detail and maintains it’s tone when overdriven but I would not say it’s real ballsy. I like this tube better when played clean.
JJ ELECTRONIC EL34: This tube when played clean is nice and linear. Not top heavy or bottom heavy but nice and centered. Over all this tube is smooth and rich with fairly complex harmonics. The distortion is thick and the detail is very nice even when driven real hard. In fact the harder you drive it the thicker it gets.
JJ ELECTRONIC E34L: This tube is very much like the JJ EL34 but it has about 15-20% more headroom. The mids are a bit more complex and it’s obvious that this tube makes a lot of power! Over all it’s a bit tighter than the JJ EL34 which is nice for combo’s or HI-FI where the standard EL34 gives more of a vintage EL34 tone. When over driven the E34L is very ballsy and harmonically rich. It’s not grainy or piercing but thick and creamy.
JJ ELECTRONIC KT77: I had to include this tube in along with the EL34 family. It is not quite a tight as the E34L but tighter than an EL34. The 77's have even a bit more low end extension than the E34L's, real chunky, and they have a nice sizzle in the top end that is not brittle. The clean tone is very fat and full and the crunch has more of a chunk to it and it's very punchy but not quite as aggressive as the E34L nor as powerful. This is one of my favorite tubes just as the original Genalex KT77 is.
Sovtek 5881WXT: Let’s see, the first word that comes to mind is "cardboard". As for describing the lows, mids and highs, three words will do it, Flabby, harsh and piercing. This tube is also sold by G.T. and re-labeled GT6L6B. The 5881/6L6WGC is the same tube with a disc base.
Sovtek 6L6WXT: This is a better tube than the 6L6GB but it still falls way short of any of the good old standard Philips and RCA 6L6’s. It’s grainy and piercing highs turn to sounding like a swarm of bees when overdriven.
Electro Harmonix 6L6EH: Another sovtek 6L6 which is once again slightly better than the 6L6WXT+ but has the same ragged tone.
Svetlana 6L6: This is now another sovtek tube that falls short of the original Svetlana in all respects.
Winged C 6L6: This is a very nice tube with nice low end, not real deep but much better than any of the Sovtek tubes including the now sovtek labeled Svetlana's. The mids are full with a fair amount of harmonic content. The highs are smooth and not piercing. This tube reminds me a lot of the old GE and Philips 6L6’s. It has good detail and the break-up is smooth and rich.
JJ ELECTRONIC 6L6GC: This tube has the deepest, tightest low end of any 6L6 I have ever tested. The mids are full of complex harmonics. The highs are sweet and down right lush. This tube is the reason I searched out JJ Electronic when I was in Europe. I imported some of them to test before my trip and was blown away by their tone and performance. My collection of RCA, GE, Tung-Sol, Philips and all the others that sit on a shelf in my tube cabinet and are now only used when other players want to A/B them to the JJ’s. When the JJ’s are biased up nice and warm they come incredibly close to that upper mid magic that my Black Plate RCA’s have but the JJ’s out do the RCA’s otherwise and especially in the low end. When over driven the JJ’s get very rich and thick. They don’t squash down and they have excellent definition and detail.
Groove Tubes 6L6GE: I really wanted this to be a good tube and they are not bad if you keep them biased at about 55% to 60% of max dissipation. Any hotter than that and they will fail in short order. The sound quality is not up to par with the original but I was never a real fan of the G.E. 6L6's, I was always more into the Philips and RCA 6L6's. The main problem I see with the GT 6L6GE tubes is the early failure rate.
PRE-AMP TUBES
Sovtek 12AX7WA and WB: I lumped these two together because there is very little difference between them. They are both pretty lack luster. The lows are shallow, the mids are sterol and flat and the highs are grainy and harsh. There seems to be no difference in tone from the silver plate WB compared to the gray plate WB. When overdriven they get thin and hairy.
Sovtek 12AX7WXT+: A little better than the WA’s and WB’s. Rounder and more linear when clean but brittle. When over driven this tube gets piercing and compresses hard. They also have a nasal like sound.
Sovtek 12AX7LPS: I think this is the best tube that Sovtek makes currently. It has better definition and is more linear than the others when played clean. It has decent detail and harmonics. When over driven it retains quite a bit of it’s definition but still seems to have that Sovtek harshness in the upper mids and highs. The break-up is not very smooth. This tube stays clean for a long time and then breaks up very quickly so it’s hard to get to that sweet spot where you can play clean by picking lightly and get distortion by hammering on.
Electro Harmonix 12AX7EH: A slightly different and better version of the sovtek LPS. A little better gain and on average a little better performing tube. These are best suited for high gain amps if you don't mind a fuzzy / buzzy high end distortion. Not a good tube for vintage amps because they lack warmth.
EI 12AX7: Once again the problem here is finding good one’s, but when you do this tube is very linear when played clean with a nice high end, not piercing or grainy. When over driven it looses a bit of low end but still remains rich and full sounding with nice harmonics. The breakup is pretty smooth. Over all this is a very nice tube and comes a lot closer to being what I would call a world class tube.
JJ ELECTRONIC ECC83S: The newer ECC83S tubes are much improved over the original JJ ECC83 it was obvious that JJ had done their homework. The new "S" tube has an improved mid and high range. It’s even more natural and smoother than the original when played clean and the chime and sparkle are top shelf. When over driven this tube has it! I can honestly say that this tube surpassed my all time favorite Telefunken 12AX7. It’s thick, lush and doesn’t compress as hard as the original. It maintains all of it’s sparkle and definition at all levels of saturation. The best in current production 12AX7 type tubes with the highest current output.
JJ ELECTRONIC ECC803S: The ECC803S's are great sounding tubes and have a very thick and fat tone with a little more high end than the ECC83S's but the 803's are lower in gain by about 10% than the ECC83S's and because of the extremely long plate in the 803S they are more susceptible to mechanical noise and feeding back at high volumes so I do not recommend them or warrantee them in small combo amps but they make a great V1 in most all heads where they provide a very thick and rich tone.