Mark III Power Tube and speaker Question

[Cooperro]

Hi Everyone,
I don't post much, but read your posts every now and then. I have a tube question, although I've had my Mark III simul-class since the mid-80's.

I'm ready to replace my 6L6's, and noticed on the Boogie website that the 5881 STR-425 is a 6L6 replacement that is "thicker" and rolls off the high end a bit. That appeals to me as my rock days are over, and I'm now a budding jazz guitarist.

So, do any of you like the 5881's? I have a store down here that stocks them.

Also, I bought a Cannabis Rex speaker with the thought of swapping it out with the stock EVM12L speaker for two reasons:
1) the Cannabis is lighter and
2) the cannabis might be more suited to that smokey L5 jazz tone I'm seeking.

I know the EVM12L handles a lot more power, but those days are over for me. And, as I'm in my 60's now, the Mark III combo is a killer to lug around.

Any thoughts on either subject would be appreciated.

Thanks,
Bob in Ft. Lauderdale

 

[xdg999]

I use the 5881’s in my Simul c+’s to tame some of highs because they are a lot brighter then my HR’s. Even with the 5881’s I have to keep the presence on 2 or lower. Mike B. told me the only 6l6’s I could safely use in the Simul c+’s are the red color coded Mesa 5881’s. I’ve blown fuses trying other 6l6’s. The 5881’s seem to be more touch responsive and thicker sounding. They’re also very durable. I have a quad of Groove Tubes 6l6B’s (Same tube as the Mesa 5881’s) that are 25 years old that still sound great.

 

[stokes]

I've no experience with the Canabis Rex,but it would seem to me that the EV would be the most suited for the clean jazz tone you are looking for.

 

[mrmark3]

One to look into would be a Eminence L'il Texas. 100 watts, 4 lbs.
Jensen has some new Neodymiums, too. I like the 65 watt for a clean Fender-type sound, with some moderate built-in breakup (believe it or not, EVs have that, too), and they make a 100 watt model as well. All 4 pounds.

 

[darkbluemurder]

When I bought my Mk III 10 years ago used it had Sovtek 6L6 WXTs in it which I understand are electronically identical to the 5881 WXT. EDIT: according to this http://www.jayskyler.com/guitar-gear-guide/sovtek-5881-wxt-6l6-wgc-tube-guide.html they are not the same tube.

Keep in mind that normally 5881 have a plate dissipation of 23 watts whereas the 6L6GC has 30 watts. And since the stock boogies have no adjustable bias some 5881s may redplate. I would follow the manufacturer's recommendations insofar. Safe operation is most important.

As regards the speaker and lugging: after many tests with different speakers and cabs I always liked the tone better with an external speaker cab. That combo cab is simply too small and chokes the bass out of almost every speaker, in particular the EVM 12 L. I put my EVM 12 L in a Dumble style cab and it sounds fabulous with the Mk III. So if you want to save weight and at the same time improve the tone, take the EVM out of the combo cab, put it in a Mesa Thiele 806 cab (or similar) and use the combo as head. Only downside is that you need more space in the car.

If you are set on using the amp as a combo: the speakers I tested in the combo cab were the EVM 12 L, the Celestion Black Shadow C-90 (which I found rather buzzy and harsh) and the Eminence Legend 12 MOD (which is close to the V12 but with more bass). I like the Eminence best so far but feel it is still thinner and peakier than an external speaker cab. While it is lighter than the EVM, the neo speakers mentioned would bring weight down even more. I really like the Jensen Jet Tornado 100W, even though I have only tested it with other amps. The power rating should be sufficient, too. Due to the small size of the combo cab I was even thinking about using a 10" speaker with a conversion ring thinking that the smaller speaker would breathe better in that small cab. I actually posted a thread whether anybody tried this already but apparently nobody did. I have a 10" Jensen Jet Tornado rated at 100 watts which I could put in but I have not had the time so far to do it.

Coincidentally I received a Cannabis Rex yesterday but I have not yet installed it so I cannot comment on its tone yet. It is said to be a warm speaker so if warm clean jazz tones are what you are after and you do not turn the amp up it could work. Since you already have that speaker there is no harm in trying. Just don't run the amp full bore as that would exceed the CR's wattage rating.

Good luck,
Stephan

 

[darkbluemurder]

PS: if you are looking for a clean jazz tone you may also consider swapping V5 (the phase inverter tube) from a 12AX7/ECC83 to a 12AT7/ECC81. Same with the reverb tube (V4).

 

[darkbluemurder]

Meanwhile I installed the Cannabis Rex in my modded Deluxe Reverb II (lead channel modded to Carvin Legacy lead channel specs). It replaced a Mesa VS-12. The amp became much bigger sounding. And the 50W rating should be sufficient in that amp. The Mark III sounded good through that speaker/cab combination as well. So for low volume playing I can see it working well in a Mesa Mark combo but I would definitely prefer the MOD since it's rated for 120W so should withstand even the models with 4 output tubes.