Help ! Mesa 50/50 with STR440 tubes sound harsh.

[JB6464]

I recently bought a used Mesa 50/50 power amp with new Mesa STR440 tubes installed but they sound harsh and mid-range dominate. Whats the best new production 6L6 out that will give the amp a smooth mid-range with a nice top-end for playing classic rock ? Does anyone know who makes those STR440 tubes so i don't buy those again unlabeled ? The STR440 tubes that are in it have the single halo on the top of the tubes.Thanks.

 

[Old BF Shred]

I can offer a suggesstion or two....

I have a 50/50 and I have always found it to be a bright amp (not unlike the Stiletto). I always keep the presence at about 2 (or less). Any higher can cause more of a harsh, brittle tone .
Mesa tubes seem to have a reputation of sounding a bit harsh, so it would seem from all the comments on this forum; I also find this to be the case, IMO. There are better, but I am not an expert on recent 6L6's as I modded my 50/50 to run el34. (This is not a simple option, however...only a qualified tech should attempt!)

I did this to address something your question brings up: "give the amp a smooth mid-range with a nice top-end for playing classic rock? ". I could not achieve this with 6L6's in this amp (at least for my ears).

I do know of some brands that seem to score high marks in tone including, but not limited to: JJ, SED =C=, TAD, as well as most older NOS or used vintage tubes.
Groove tubes likely offers models that will be an improvement as well.
I will say that the 50/50 is a great power amp....Mine has been absolutely bulletproof. I drive mine with a Triaxis and it is an awesome combination! So there is hope!

Good luck!

 

[JB6464]

Thanks for your info MarkIII. I was wondering if i could mod the power amp as well to take EL34's(Winged=C=)but was'nt sure if it was possible. This is my first Mesa setup i've ever owned.(Quad Preamp & 50/50 power amp)I've always been a Marshall and Carvin player for over 25yrs and i'm now just getting into mesa gear. Is the mod easy to do for a amp tech ? I have a quad of SED =C= EL34's i can put into the power amp.

 

[Old BF Shred]

Modding to el34 is not particularly complicated, but needs to be done by someone with experience with servicing tube amps. As you have likely heard, there are dangerous high voltages in there that can kill, even for many, many hours after being unplugged.

Hopefully you have a shop in your area that can do this; if anyone says "it can't be done", look elsewhere as many on this forum, besides me, have done it successfully.

However, be aware that your amp will sound different and you may not like the results....the main thing will be a noticable loss of low end. You will not get the same "chunk and thump" you get with 6L6's. That did not bother me, but you may not want that. It is still easier to try a better 6L6 and see if you like that before spending $ to have it modded.

Again, good luck!

 

[fishyfishfish]

You could try leaving your amp on for a while. I noticed that when I re-tube that sometimes sound harsh and "Metallic" sounding for about 40 hours or so.

 

[crane]

I like my 50/50 with SED =C= 6L6. They sound perfect ! Rich bass, creamy mids and nice top end, not harsh at all.
But you have to do a bias mod to find their sweet point, they are not Mesa-graded.

 

[R_ADKINS80]

I like my 50/50 with SED =C= 6L6. They sound perfect ! Rich bass, creamy mids and nice top end, not harsh at all.
But you have to do a bias mod to find their sweet point, they are not Mesa-graded.

I have Mesa labeled =C='s..hey are the STR454. You shouldn't have any problems getting =C= tubes in Mesa specs from any DECENT tube vendor.