295 Power Amp Tube Questions - All 6L6's?

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rockguy66

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Hey Guys,

I just purchased a 295 Simul-Class and it was fairly dusty inside, so before I used it I decided to clean all of the dust out. Being new to this amp, I marked all the tubes with a sharpie to denote their positions so i could put them all back in place. I covered the sockets with masking tape so as to not get any dust/debris inside. I took a soft bristled, brand new paint brush and went about cleaning as I did not have any compressed air. Once I was done, I took a quick look at the tubes. All of the Power tubes were 6L6's, 6 of which were SOVTEK and the remaining two were Philips. I was under the impression that the Class A Mode tubes were supposed to be EL-34s? Even the diagram on the inside of the amp shows different tubes (6CA7). Could this have damaged the amp at all? I know I should have given it the good old listen, but this guy was leaving town, had to grab it from storage and was letting it go, down from $450.00 to $350.00 for me. I am new to the whole tubes scene (I had a guitar tech take care of it all for me) so pardon my noobishness. Also, I got the interior pretty clean, what can I do to clean the residue off of the tubes themselves? They feel a tiny bit gummy, I just figured since I had them out I would try and clean them as well.

Thanks for your help and patience,

Barrett "Rockguy66" Hamilton

P.S. I know there are also 4 12AX7s in it as well, they were in there in the proper position according to the decal.
 
Ive never owned or seen a 295 but if you look up the manual, it sounds like it uses both El34s and 6l6s.

The power tubes used in the 295 are MESA STR-420 type 6L6 GC's, and MESA STR-440
type EL-34's.

Look up some photo's on google. It looks like you need to remove the top. IN the center are the 6L6s, then on either side are pairs of EL34s, followed by sets of 12ax7.

Check out this link for pics of the under the lid.

http://kleinanzeigen.ebay.de/anzeigen/s-anzeige/mesa-boogie-simul-class-295-preissturz/67417138-74-2721

You only removed a 3rd of your tubes!!!! you have eight more to go!
 
Hi,

No, I actually removed all 12. There are , moving from left to right, 2 12AX7s, 2 6CA7s, 2 6L6s. Then, it keeps going in reverse as you go to teh right... 6L6/6CA7/12AX7. My issue is, there were NO 6CA7( which are El-34s I believe). In the place of the 6CA7s were more of the 6L6s. Everything I read so far, in that position should be the El-34 style tubes, which will give you the Class a Triode mode, 30 watts per channel. What I want to know is, can that possible have messed up the amp, the previous owner using all 6L6s in the amp, other than the aforementioned 12AX7s. I hope this makes sense, I am in the midst of a migraine and I think some of the dust I inhaled from cleaning the amp might have been from some smoky club back in the late 80s....

Thanks,

Barrett
 
Check this out. being new to amps you may want to take it to a qualified Mesa technician to have it looked over.


http://forum.grailtone.com/viewtopic.php?f=5&t=58789
 
Hi rockguy,

It's possible to run the amp with all 6L6 in, if the outer ones are selected for the fixed bias designed for EL34...
But I would recommand to run EL34 in the outer sockets. Mixing tube type in that amp really bring something special, full, wide, magic to the sound.
That may be the "missing thing" in my MkV...
 
Thanks for all of your input guys, and thanks for the link to the previous posting on this subject. I actually talked to Kris over at Mesa and he said the only thing running those 6L6s in the EL-34 slots would do is possible damage the tubes themselves. I also have the old Simul-Class 295 with the output POT on the back and only a presence switch instead of the presence Pot, but the quad has more than enough tweaking for the sound. The only way I would probably need the presence switch is in a live situation as a mid/high boost to cut through the mix better. At this point, I will be using the Class A section only, for volume reasons as I live in a Condo....

I just ordered a Quad set of Ruby EL-34s from Musicians Friend for $54.00 , I wish I would have found this board sooner. I know Mesa uses Ruby tubes stock, but after reading through some ports here, that might not have been the best solution. Next, I will have to get the tubes for my Quad Preamp, anyone have any suggestions on that?

Thanks for all of your help!

Barrett "Rockguy66" Hamilton
 
Ruby tubes are just rebranded tubes, Ruby doesn't manufacture tubes, Mesa tubes are re rebranded tubes, I could buy tubes from them and put my name on them and sell them to you too..............Best tubes out there are NOS, one of my fav's is RFT (12AX7), still love JJ's too, yes they are a manufacturer, one of only a few, Eurotube sells JJ's and is a distributor, but they don't rebrand them or put their name on them, the customer service is the best of the best of the best! I don't and won't use ANY chinese tube, reliabilty and tone is the worst of the worst of the worst.

Yes maybe Mesa uses Ruby, but Ruby probably gets their tubes from JJ and sells them to Mesa. (12AX7)
 
Hi Mesaboogie6L6,

I can undoubtedly agree with you that the Rubys are in fact JJs. They are just tested to fall into the tolerances that are acceptable by Mesa, from what I was told. Mesa just rebrands them. I only ordered the Ruby's because I needed to put some EL-34s in the Class A section of my 295, as the previous owner was running all 6L6s. I wish I could afford the NOS tubes right now, I was able to get a Quad of matched tubes for $54.00 shipped. As it sits right now, I can't use it without tubes, so I ordered those to get it up and running. I have spoken to Doug from Doug's Tubes since then, and he educated me a bit so when I get paid next week I am going to put all of the right tubes in the right places...

Thanks for your help and input!

Barrett
 
Hey Barrett,

If I can help out someone on this board, I'm more than happy too, I've learned so much about Mesa amps and tubes it's priceless, thanks to ALL the members and their knowledge, it is greatly appreciated!

Glad you are headed in the right direction, simul 295 amps are badass, good luck with it and your tube buying, Doug is a good guy and knows his stuff, I've bought from him before.

I want a strategy 400 or 500.
 
fwiw, I got a quad of new reissue Mullard EL-34s from The Tube Store for my 2:95. They matched them and ensured the correct specs, and they sound fantastic. Not a bad choice of tube imho.
 
I've heard good things about those, nice choice in some new glass!

Although I'm not a fan of EL34's, I like 6L6, KT88, KT66 and 6550, tried some KT77's and 6L6 (simul-class) in my Coliseum, didn't sound bad, just wasn't giving me the deep low end I'm used too, anyone who has a Coli or played through one knows what I'm talking about!
 
Ok I might be a few months late but. The 6CA7 is EL34, its a better variant, if you find a Sylvania fat bottle with dual halo getters on top thats the old STR 416 used it the 80's boogie's. And enough of the old "these guys just rebrand tubes" look up all the stuff on tube manufactures. Tubes are made in Russia, China and a Czech company Tesla a couple more making hand made tubes mostly for HIFI systems thats all thats it no other manufactures... Mesa,GT, Ruby, are screeners testers. They buy thousands of tubes weed out the crap put there name one the best ones. Well If you have a newer Mesa Boogie you have to use there tubes or void your warranty.But for the old Mark 2's & 3's you need NOS preamp tubes. Start with V1 I use NOS Mullard 12AX7 or 7025 dependeing on witch amp .MK3's need more gain & output, but my Quad Pre CH1 witch is MK2C+ clone works great with RCA 7025 in V21 witch is hi gain lower output than Mullard 12AX7 . I am a Engineer and I have a power tube tester I made from a Peavey windsor and a Hickok 752A for preamp tubes so I have a large collection of NOS tubes. The EL34's and 6L6's from the 70's 80's last 10000 hrs and sound great listen to VanHalen 1 & 2 thats the sound of 6CA7=EL34's in a Marshal Super Lead .Now listen to Metallica Master of puppets thats the sound of Mesa Boogie MK 2C+ with both 6CA7's & 6L6's vintage tubes.
 

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