JJ EL844 tubes in a DC-3

Just curious to see if any DC-3 owners out there have tried these yet.
http://www.eurotubes.com/euro-EL844.htm

I bought a DC-3 a few months ago. The previous owner had put in 4 JJ EL84 tubes and it sounded pretty good with the expected high-mid emphasis. I recently replaced them with JJ EL844 tubes. The tubes have a 25% reduction in power dissipation (12W down to 9W). This does not automatically translate to a 25% reduction power output and from many sources I heard that the power reduction may not be all that noticeable. But compared to the hot JJ EL84's there were in there before, the drop in volume was noticeable, though not extremely dramatic. It basically made the output level knob more bedroom friendly, and that was my main goal.

Another noticeable change is the heat, or lack of. With the EL84's, the power and standby switches would get hot after the amp was running for 20-30 mins, even at bedroom levels. This is no longer the case with the EL844's. The switches remain cool to the touch.

Now, for the most important part: how it sounds. The marketing line I have seen is "Reduced power and a more balanced frequency response" and so far it is true. The "balanced" response is a lack of the jangly, high-mid emphasis of the EL84, resulting in a flatter frequency response. But I did notice a slight loss in bass response. No problem, though, the bass controls were previously set low on both channels. I just increased the levels, no big deal. I also preferred the sound of the EL844's when driven to the breaking point. It actually reminds me of JJ's ECC83S (normal gain 12AX7). The EL84's had a certain harshness in this DC-3 when driven hard, being that this is a very midrange-heavy preamp, and the typical response of EL84's.

I have yet to try it out with a drummer or in a band setting, but it still sounds like it has enough power to hang with a loud rock drummer.

I'm still holding on to the older EL84 tubes as backups, and if it needs a little more juice, swapping either the inside or outside pair of power tubes might do the trick.

This tube is highly recommended if:
1. You want some power reduction in any EL84 based amp
2. You want a little change of tone, a smoother tone than normal EL84's
3. Just want to try something different
4. Tired of your DC-3 running up cooling bills

This sounds exactly what I have been looking for to tweak my DC3. A smoother-warmer sound at lower volumes.

What needs to be done to rebias the amp going to these tubes. I should probably take the amp to my tech.

Thanks,
Doug

Very interesting post. I've been using all JJ's in my DC 3 and it sounds great, but I notice the back does get a little hot (although not any hotter than my Marshall DSL does).

The only odd thing I read in your post was that you mention how the power and standby switches get hot after leaving the amp on for 30 minutes. Mine doesn't do this, as the switches are always cold (I have the metal kind). I'm not saying there's anything wrong with your amp, it just caught my attention.

MarshMesa said:

The only odd thing I read in your post was that you mention how the power and standby switches get hot after leaving the amp on for 30 minutes. Mine doesn't do this, as the switches are always cold (I have the metal kind). I'm not saying there's anything wrong with your amp, it just caught my attention.

Click to expand...

Same here. My switches don't get hot even at the end of a 4 hour gig. Running JJ el84.

MJ Slaughter said:

MarshMesa said:

The only odd thing I read in your post was that you mention how the power and standby switches get hot after leaving the amp on for 30 minutes. Mine doesn't do this, as the switches are always cold (I have the metal kind). I'm not saying there's anything wrong with your amp, it just caught my attention.

Click to expand...

Same here. My switches don't get hot even at the end of a 4 hour gig. Running JJ el84.

Click to expand...

I think a previous owner had the bias adjusted and the tubes run hotter than normal. The factory set fixed bias for MBs tend to run the tubes a little on the cooler side, from what I understand.

I had been considering taking it to a tech to get it set back to factory specs. But the EL844s seem to run well at the current bias, so it may not be worth the money.

DC3 Gridlock said:

This sounds exactly what I have been looking for to tweak my DC3. A smoother-warmer sound at lower volumes.

What needs to be done to rebias the amp going to these tubes. I should probably take the amp to my tech.

Thanks,
Doug

Click to expand...

I believe you can get matched quad set from Euro tubes and request that they send ones within MB's specs. If your amp's bias is still factory set, that could be a route to take.

Another tip:

http://forum.grailtone.com/viewtopic.php?f=28&t=52634

I put a 12AY7 in the PI (V6, leftmost preamp tube when looking from the back) as discussed in that thread. It's a lower gain replacement for the 12AX7.

gibsonboogie,

How is the affect on the headroom on the clean channel? I got an email reply from Eurotubes that the EL844's are not a good choice if I still want a clean sound at a moderate to high volume. They said that the tubes would start to break up at a significantly lower volume.

I was thinking that the stock tubes gives me way, way more headroom than I would ever need. I was hoping that with the EL844s, it wouldn't start to break up unless I cranked up the gain on the clean channel. And with a low gain setting, I could still get a clean sound as long as the gain was set low.

photogold said:

gibsonboogie,

How is the affect on the headroom on the clean channel? I got an email reply from Eurotubes that the EL844's are not a good choice if I still want a clean sound at a moderate to high volume. They said that the tubes would start to break up at a significantly lower volume.

I was thinking that the stock tubes gives me way, way more headroom than I would ever need. I was hoping that with the EL844s, it wouldn't start to break up unless I cranked up the gain on the clean channel. And with a low gain setting, I could still get a clean sound as long as the gain was set low.

Click to expand...

There is definitely less headroom. I normally play channel 1 with the gain just at the point where the preamp tubes start breaking up. So I really don't play with a completely clean sound.

But that being said, you should be able to keep channel 1 clean if you keep the gain and master low... to a certain degree. It really depends on how loud you want it. If you normally play your amp pushing at 75% max power, that would already be the max power of the EL844 and you'll get full power tube saturation. But if you normally keep the output power at 1/2 or lower, which on the DC-3 can still be loud, you'll probably be fine. Keep in mind that pushing those tubes don't always result in a noticeable level of distortion. Right before the point of noticeable break up, these do have the trait that all good-sounding power tubes have where it seems to fatten the sound up with some compression and sustain.

gibsonboogie said:

MJ Slaughter said:

MarshMesa said:

The only odd thing I read in your post was that you mention how the power and standby switches get hot after leaving the amp on for 30 minutes. Mine doesn't do this, as the switches are always cold (I have the metal kind). I'm not saying there's anything wrong with your amp, it just caught my attention.

Click to expand...

Same here. My switches don't get hot even at the end of a 4 hour gig. Running JJ el84.

Click to expand...

I think a previous owner had the bias adjusted and the tubes run hotter than normal. The factory set fixed bias for MBs tend to run the tubes a little on the cooler side, from what I understand.

I had been considering taking it to a tech to get it set back to factory specs. But the EL844s seem to run well at the current bias, so it may not be worth the money.

Click to expand...

No,the factory set bias on th DC3 is set hotter then a pistol. -11v with the plates running well above 400 volts.

gibsonboogie said:

There is definitely less headroom. I normally play channel 1 with the gain just at the point where the preamp tubes start breaking up. So I really don't play with a completely clean sound.

But that being said, you should be able to keep channel 1 clean if you keep the gain and master low... to a certain degree. It really depends on how loud you want it. If you normally play your amp pushing at 75% max power, that would already be the max power of the EL844 and you'll get full power tube saturation. But if you normally keep the output power at 1/2 or lower, which on the DC-3 can still be loud, you'll probably be fine. Keep in mind that pushing those tubes don't always result in a noticeable level of distortion. Right before the point of noticeable break up, these do have the trait that all good-sounding power tubes have where it seems to fatten the sound up with some compression and sustain.

Click to expand...

I don't play that loud. With stock EL84s, I have way more headroom than I would ever need. On the clean channel, if I have the gain and master both at 5, there's no way I can turn the Output past 2 without blowing out the windows, or everybody's ears. With EL844s, do you think I could set the gain and master both at 2, and the output at about 4, and still maintain headroom with no compression? Could I maintain headroom with a moderate drummer? I would use this for small to medium gigs, but not really loud stuff. Most of the time, I would't want the clean channel completely clean, just a slight crunch like you. But with stock tubes, it seems that I can't get anywhere near the point where I push the power tubes at all. And I'd like to have access to that "pre breakup" point. And on the gain channel, I'd like to get a screaming lead and push the power tubes without extreme volume. But I'd like to have clean available if I should need it.

Here's a reply from Jay at Eurotubes. What concerns me is his statement "clean headroom is next to nil with the EL844’s":

If you want the earliest possible breakup from the power tubes, then the EL844’s are the ticket. With this in mind, for a workhorse amp used for gigs where you simply want to keep overall volume down, I would typically recommend EL84’s graded for early breakup. This option will yield a more useable clean channel when you’re competing with a drummer, while clean headroom is next to nil with the EL844’s. In other words, using EL844’s your clean channel will only stay clean at significantly lower output settings.

All that being said, as a general rule you will not ever achieve power tube breakup at low volumes. Whether it’s a 5-watt pea shooter or a 200-watt monster, you have to crank it and push it to get that extra saturation. It’s the power dissipation and how hot the tubes run (~via bias setting or tube grade) that determines how much sound pressure there will be when you get that saturation.

photogold,
I would say there is only 1 way to really find out, and that's by trying. I played a little loud this past weekend with another guitarist and bassist, no drummer. I still had the output levels rather low, so I would say yes, there should be enough headroom. I'd say that account from Eurotubes does not reflect my own experience, especially the part of "clean headroom is next to nil with the EL844’s". It could very well be the case in some amps, but not in my DC-3. One of the first things I did when I put the EL844's in was to hookup my power attenuator to find out the breakup point. And while it was lower, I still had to turn the output level past 5 before any noticeable additional break up occurred ( I have the masters around 3-4, gain on ch1 around 4-5). The DC-3 power section is rated at 35W with EL84, and I can only assume that they were rated with MB tubes. The EL844 has 75% the power dissipation of the EL84. Take these approximate numbers for what they are worth, but 75% of 35 watts is 26.25 watts.

gibsonboogie,

Yes, I agree. The worst thing that can happen is that I would need to order a new set of EL-84's if the EL-844's didn't have enough power. And that wouldn't be the end of the world.

If I had a DC-2 with only 2 power tubes, then I would be more concerned about headroom. But with a DC-3, that should be less of a concern. I wonder if the net effect is that the EL-844's make the DC-3 more like a DC-2 with EL-84's?

I think I'll give the EL844's a try.

+1 on trying a set...

I've played out a few times with my DC-2 running EL-84's and even with a really loud drummer, I've never been even close to being dimed on it. I've used the combo speaker sometimes and I've run my 4x12 a few times as well...I've got lots of pedal left. Sooo....with your DC-3 I'm not really sure how "quiet" you're going to wind up in the end. Sometimes headroom can be kind of subjective. All you can do is try 'em out and see what it sounds like. If nothing else, it will be a fun experiment. :mrgreen:

Good luck!!