Problem with new old mark III

[Mr.P]

Hi guys. I recently purchased a mark III from a guy in another town. It arrived today, now I have some issue with this amp. It's in perfect working condition (clean channel sounds good), but the lead sound isn't up to my expectation.
1. There's too little gain on the lead channel. At 10 it sounds like the clean channel with a bit of breakup. Nowhere close to clips and reviews on the web. Now what might cause this?
2. The seller said it's a green stripe, now the only thing I see near the power cord is a blue marker stripe, is this a blue stripe?
3. The previous owner put 4 JJ 6L6GCs. This is a simul class unit. What's the consequences of using non mesa tubes? Shorter tube life or does it damage the amp?

 

[destropiate]

Is the volume up in the 7-10 range? For the lead to really get cooking you have to up the channel 1 volume and then bring it down to a comfortable level with the master. If that still doesn't work it's probably a preamp tube problem.
For this amp the manual is really worth getting as the design is different from most other amps. It will help you get some good tones to start off with from the sample settings. According to the manual they want El34's in the outer sockets. That's how I run mine. I don't think it will damage the amp with 6L6 tubes but mesa suggests the 34's. You can use non mesa tubes as long as they are in the same range as the non adjustable bias in the amp.

 

[MrMarkIII]

Should we assume that all four 6L6's were bought and installed at the same time?
IOW, are they all matched to each other, or are they matched in pairs?
Power tubes are usually matched in pairs.
In a Mark III, they should be installed in the sockets like this:
Y X X Y
You see that there is an outer pair (Y Y) and an inner pair (X X).
The Y Y pair should be matched to each other.
The X X pair, likewise.
All four can be matched together, but it's not necessary, so beware of tube sellers who charge more for a "matched quad".
Try these settings to start:
Volume 1 = 7
Treble = 7
Middle = 5
Bass = 3
Master = 3
Lead Drive = 5
Lead Master = 3
Pull out the Middle control to engage the Rhythm 2 sound.
Pull out the Lead Drive knob to engage the Lead sound.

 

[Mr.P]

Thanks guys, it sounds better now after I read the manual, the control does behave unlike any other amp.
Still, I think it might have faulty preamp tubes, even with volume1 and lead drive on 10 there's not enough gain. I will try swapping around the V3 tube later today.
The bottom end is quite muddy as well. Is this a common problem with the combo version? Mine is equipped with EV speaker.
MrMarkIII thanks for sharing your setting, sounds really good!

 

[destropiate]

One of the tricks to this amp is to keep the bass really low on the regular controls and then dial it back in with the graphic EQ. My settings look allot like the previous posters but for really high gain stuff I have it at 1 or even 0. This is because for metal or heavy rock I like the way it sounds with the deep V shape with the graphic that Metallica basically made famous. The interaction between the regular controls and the graphic is one of the things that really makes this amp shine IMO. Some people are turned off though cause it can take some work to dial in your sound.
Congrats on the new amp BTW!

 

[Mr.P]

Hi guys, I want to update about my amp situation, it turns out the JJ power tubes the previous owner installed was way outside mesa's bias range (also, it wasn't a matched pair/quad)
I put 4 mesa STR440s in the power section, and now it sounds VERY good. Harsh treble is now gone, the midrange is very 3D, and there's big increase in amount of gain available. It still lacks some bottom end, but sounds quite thick and balanced across the spectrum. I might change the preamp tube as well. Any recommendation?

 

[4406cuda]

You will get an increase in bottom end if you plug in an external cab, especially a 4 x 12