JJ Electronic tubes continue to win converts for their reliability and consistency, so it was seriously interested when I heard about their three new power tubes: 6CA7, 6550 and a new tube called an EL844.

We recently covered the 6CA7 over on WoodyTone.com, so here’ we’ll just deal with the other two.

To find out more about thee tubes, I talked to Bob Pletka at Eurotubes, who works closely with JJ. My first question to him was a generic one: Why did you request these tubes be made – were they in response to specific customer requests for particular tonal goals? Here’s what he said:

“The EL844 was something I was working with JJ to produce for several years, to give players who use EL84 amps earlier break-up and the nice, tight, focused sound they needed. I felt there was a nice niche in the market.

“The 6550 was later on the list, and I was actually a little bit surprised they got it done as quickly and as good as they did. We wanted the 6550 to get a big-bottle sound in amps that didn’t have [enough] spacing between the sockets [for KT88s].”

Now to each tube individually. All quotes are from Bob.

6550

AmpGAS: Why a new 6550? Doesn’t seem like many folks use them these days, including manufacturers.

Bob: One of the strongholds for 6550s is a lot of guys who own the old 800 series Marshalls and don’t really want to make a change [to EL34s – many JCM800s sent to America were given 6550s because of EL34 issues at the time – I think I got that right!].

Also, a lot of bass amps, like Ampeg SVTs, run on 6550s so that’s a standard.

What does the new 6550 sound like?

The best way I can say it is that it has a growl to it when it breaks up – kind of a Billy Gibbons thing [Gibbons?! Marshall?! Love it!]. They sound really musical. They don’t have that rattier type of break-up.

Take some of them and stick them in a 50- or 100-watter and crank it, and it’s pretty impressive. It does something that no other tube that we have does. It has a pretty unique sound to it, and so far everyone who’s tried them has been blown away.

It does that 6550 clean thing – big, fat, sparkly – too, but that growl….

We were probably most taken aback by the 6550 out of all three [new] tubes for how unique it is.

Other than Slash and Ace Frehley, I’m not familiar with anyone else who has used 6550 tubes for a signature rock tone. So what tones would you recommend this tube for reproducing?

Well, there was a short period of time when SRV was using them. He used them a few different times and was fairly impressed with how they were when he really got them cranking.

But I’d say lot of people used 6550s [in JCM800s] who didn’t know they were using 6550s. A lot of 800 Marshalls came with 6550s in them and they were decent 6550s – a lot were American-made. I think a lot more people have used them and didn’t know it [and thus we don't either!].

How does a 6550 sound different than a 6L6?

I’d say if you want nothing but a clean sound with a great top end sparkle and lot of warmth and your mission is not to overdrive, stick with 6L6s. But if you want to slap a pair of tubes in a 50-watter and want a really good clean – better than with EL34s – and a growl when really cranked, the 6550 contender for that.

EL844

AmpGAS: The new EL844 – how does it sound different than an EL84?

Bob: The mission was to get it to sound as close as possible. Over the last almost 3 years JJ has been working with the design and sending us prototypes, it was actually quite a different tube. Now it’s so close to an EL84 that if I had to pin a difference it just makes less power, breaks up earlier and seems to be a little bit more focused when you really drive it hard.

What’s the best way to use this tube?

We get guys that call us all day long, every day. Some say, “I’m playing through my [Fender] Blues Junior and it’s not loud enough. I need 2 times as much power, what tubes do I need?” I tell them go fish [laughs].

On the other hand more say their Blues Junior is so loud the wife is throwing stuff at them. So those bedroom, basement players like to get their amps up to that sweet spot, but 15w is pretty loud, especially if you’re playing for a number of hours. So our mission was to get a tube that sounded like an EL84 but made less power.

We wanted to see if we could make an EL84 substitute that makes 5w. We ended up with protoypes that make 9w, 25% less power, that you could plug in and not worry about the bias. That was the biggest thing, that they’d fall into a range useable in [amps like a Blues Junior, a little Bad Cat, a Peavey Classic or even a Vox AC30] without having to worry about it.

JJs

AmpGAS: Many touring musicians now favor JJs because of their tone and also hardiness on the road. What’s the secret sauce here – is it just manufacturing consistency or…?

Bob: I’d say it’s the time they take to do it right, and also the glass they use is thicker than you’ll find on almost any tube out there. I really think that has something to do with how robust everything is.

When you break down what happens in a tube, basically it’s held into position by how it’s wired up and by the mica spacers in the tube [what you see at the top and bottom, which actually touch the glass]: You can’t hold the guts too tight because the metal will expand at a much greater rate than glass. I think the thicker glass and holding the insides more precisely are that what gives them an edge in how rugged they are.

Note

> Bob knows his sh*t inside and out. Any factual screw-ups are mine – and please note any! Thanks!