Mesa modification info?

[ZR4400]

I recently purchased a Mesa MKIIB Coliseum, with the loop modification. It has an extra "volume" knob on back that acts like a attenuator. The amp is an absolute MONSTER. Hands down the best amp I have ever owned.

I am not so sure that I don't have additional modifications besides the loop mod, but I would like to know for sure.

I am wondering if Mesa would have kept track of the day the amp came back in for the loop mod, and the work that was performed?

There is writing from Mesa on the chassis that shows the "born on date" (LJ 3/5/82) and a couple preamp tube replacement dates (NEW 9/99).

Although I have never played a 2C+ or ++, I am wondering if I don't have something close?

From what I have read on the interwebs, the IIB loop mod adds additional gain, putting the amp somewhere in between a IIB and IIC.

Thoughts?

 

[Tone Monster]

call mesa?

 

[NinjaRaf]

Yeah, I would just call them. They are super helpful. If they kept those records, they will have them probably based on serial number.

 

[Markedman]

You’re in MN, is that the missing Prince amp? He had Mike at Mesa mod two and one was found.

 

[ZR4400]

I have no idea, but I know it SLAYS every amp I have ever owned. I purchased it in Roseville MN.

I did the loop test as mentioned in the FAQ section of the Mesa site this evening. After doing the test, I might have a IIB converted to a IIC+

I am going to give Mesa a call in the morning.

 

[steve_k]

If it was upgraded to a C+, there will be a + sign and MB's initials by the power cord, top left. Most all Mark amps back in the day will have the tube types written in marker on the chassis. The KRG is also there from Mesa indicating Colosseum (K) with Reverb (R) and GEQ (G). You can confirm the loop mod by plugging your guitar into the loop send and turning the MV up. if the volume doesn't change, then it is a modded loop.

 

[ZR4400]

It has the initials (MB) in the top left, but no plus sign.

Here is a photo of the loop mod/volume pot.

Not sure why the photos are spun. ??

 

[GJgo]

I think that might be Racerxrated's old amp. Might ask him.

 

[Racerxrated]

I think that might be Racerxrated's old amp. Might ask him.

We've already chatted. Wrong serial#. My old one was K26X.

OP, call Mesa Customer service and any of their reps can tell you what's been done to it with the serial.