MkIII Blue Stripe Lead Tone Settings/C+ Mod

[Ed Mullins]

I own a blue stripe MkIII long head and am having trouble getting the lead tone dialed in. If I set R1 for a Fender clean tone then the lead channel is a little harsh on the top end. Would the C+ mod give me a smoother lead channel or just a 'Master of Puppets' grind? I'm after a smooth/Santana-ish type lead sound along with the Fender clean on R1. My speaker cabinet has a Celestion 70/80 speaker. Is this part of the problem?

 

[Joey707]

What are your settings? The speaker could be part of the problem. I tried that speaker once and found it too bright for me. I has a smaller magnet than the M/C 90 or the V-30 so you'll get less bass. Tubes can also be a factor. What pre amp and power tubes are you running?

 

[Ed Mullins]

My settings closely resemble the rock sample settings from the MkIII manual.

Volume = 6.5 pulled
Treble = 7.5 pulled
Bass = 3 pulled
Middle = 4
Master = 2 pulled
Lead Drive = 7
Lead Master = 5
R2 Master = 6
Presence = 4
Reverb = 6

Not sure about the tubes. I'm not very knowledgeable on this subject. I bought the amp used and am still running the same tubes it came with. The amp sat in a closet for close to 15 years so these could very well be the original tubes. From what I can see the power tubes are labeled 6L6GC in the inner pair and 6CA7-EL34 outer. The preamp tubes are marked STR-12AX7-A. Can't see the labels on all of the preamp tubes though.
I'll try a different speaker as you’ve suggested and see if that helps.
Thanks for your help.

 

[Joey707]

The tubes are pretty old. But it's impossible to know how much use they saw before the amp was parked in the closet. Another thing you may want to do if you haven't already is to give the amp a good general cleaning. Pots, jacks, tube sockets, etc. Be sure to clean the reverb RCA jacks on the amp and the tank. Dirt can contribute to bad tone.
If you decide to change tubes I've had good luck with the Electro Harmonix, and Tung Sol 12AX7's. I've heard that the JJ's are good as well. If the power tubes are the original USA made tubes try to save them. The sound great and can't be replaced inexpensively.

 

[Ed Mullins]

The power tubes are USA made versions. Glad to hear they're valuable. Not sure how many hours of use the tubes saw before being parked. Probably not much use based on the amps condition. I did recently clean the amp and all the pots. It's in spotless condition and works flawlessly. I'm starting to agree with you that the speaker might be a little bright and harsh. A friend is gonna loan me a cabinet with a Vintage 30 and another with a Tone Tubby. We'll see what that does for the lead tone.
Any advice on the C+ mod? Is it a smoother lead sound than what I have now or a more scooped metal sound?
Thanks for all your help.

 

[Joey707]

If possible you should also try a Mesa/Celestion 90 watt speaker. I had the C+ mod done on my amps. I think it's smoother sounding not scooped at all. If you're looking for a Santana type lead sound it should be right up you're alley.

 

[Ed Mullins]

I'll try to find a Mesa/Celestion 90 before making a final decision. Will probably call Mesa Boogie this week for an RA# to have the C+ mod done. I'll let you know how it turns out.
Thanks again,
Ed

 

[DW]

You really need to try new power tubes in there before you send the amp to Mesa for the III C+ mod. Power tubes are to an amp what strings are to the guitar--they need changing once in a while.

Once you have new 6L6's and EL34's, I also suggest dialing up Volume 1 and the Treble knobs to 8.5 or so and lowering the Bass to around 1 or 2 and the Middle to around 2.5.

If your amp has a graphic EQ, put the middle slider right at the center hash mark and put the others in a V pattern.

Of course if the amp sat unused for 15 years it could indeed need some work as filter caps can dry out if they don't get some current running through them every so often.

 

[Ed Mullins]

I'll certainly try new tubes first but if the amp suffered from power tube troubles wouldn't all 3 channels sound bad? I can make R1 & R2 sound great but the lead channel becomes harsh. If I make the lead channel smooth then the R1 & R2 sounds aren't as good. I'm pretty sure the amp is in very good health. I've read on this forum that other MkIII users sometimes have trouble dialing in 3 good tones with a single group of settings. Just wondering if the C+ mod would make it easier to dial in three great sounds without having to adjust the volume, level and EQ knobs?

 

[Ed Mullins]

I replaced the Celestion 70/80 speaker in my cabinet with an Eminence Governor. The MkIII sounds amazing with the Governor speaker. The Eminence website suggested the Governor as a direct replacement for a Mesa/Celestion 12" speaker. The Celestion 70/80 speaker I was originally using may have been the source of my problem all along. The lead channel now sounds amazing along with a good clean channel and R2. No harsh top end to be found anywhere. Thanks to everyone that responded and offered advice.