Help: Which Mark Is This...?

[MetallicBlueAx]

Hey,

So I'm pretty confused about this. This is my dad's amp and I've just started using it. I can't really figure out if it's a IIB, IIC, or IIC+... It has the + and MB initials by the power cord so that made me think it's definitely a IIC+, but my dad still has all the original info that came with the amp, and they sent him the schematics for a IIB, so that's where I'm not sure. Here's some pictures:

So, from those, what is this amp exactly? Any and all info about it would help. Also, I found that turning up the amp to 2 starts getting a high pitched squealing sound, and any higher and it is an extremely loud sound. Turns out the SPAX7 tube is microphonic, so we ordered one to replace it. Does that sound like the right thing to do? Thanks in advance.

- Mick

EDIT: The serial number is... 14212

 

[Aart]

IIC+

You're lucky.

 

[Aart]

Its a IIB modded to a IIC+ by Mike Benelli.

 

[MetallicBlueAx]

Awesome... so, does that mean they had a IIB around and just upgraded it to a IIC+ before they sold it to my dad? Or how does that work? Because he said that he bought it, but then never had any sort of work done on it after that. So I'm wondering if it can be a modded amp like that even if he basically got it new. Thanks.

- Mick

 

[Aart]

well, it has to be brought to M/B for the mod, so yes, there is work done by the previous owner.

Maybe this one is modded in the factory, if your dad bought it new.

But you're(or your dad is) a lucky *******, because this is a fine piece of amp technology.

Try these settings(flemming rasmussen noted these when recording MoP):

Rythm Battery:

Top of the sheet is the horizontal row of #s with three of them circled. They are the amp (Mesa MkIIC+) settings, circled means the knobs are pulled out.
Volume=9.5, treble=7 (pulled shift adds gain and balls in lead mode only), bass=2, middle=4, master=4 (pulled deep adds low end fatness for rhythm and lead), lead drive=5 (pulled lead manually selects lead), lead master=3.75, and presence=4.5, which is on the back of the amp.

Below that is the obvious graphic eq setting.

the sheet can be found here(with geq settings)

http://www.sweetsilence.com/Metallicanotes/04-Battery%20Gtr%20EQs%20Small.jpg


And then play 'tallica 8)

 

[Boogiebabies]

 

[jay]

DEFINATELY A C+. THAT AMP IS BEAUTIFUL AND LOADED. WISH MY DAD HAD ONE.

 

[MetallicBlueAx]

Hahaha, awesome! Ok, I have another question or two...

So, the first thing I guess regards the tubes. We re-tubed the whole thing maybe 2 years ago... this included buying (all Mesa Brand)...

4 Power Tubes (I can't remember the model, 6L6 or something?)
4 Preamp Tubes - 12AX7's
2 Preamp(?) Tubes - SPAX7's

So, I believe that it only actually uses 1 SPAX7, as there's a spot (looking from behind the amp) in the bottom left to hold another small tube like that. So, theres the 4 big power tubes up front, with one 12AX7 on the left of those. And then behind those (looking from behind the amp still) there is a row of 3 12AX7's, and in the far right corner, an SPAX7... this one has some sort of metal shielding on it. We noticed tapping this tube it was very microphonic.. if the amp is turned up past 2 it starts squealing pretty bad.

I tried switching the SPAX7 with the 12AX7 near the power tubes, and it seemed to make a huge difference with the tone of the amp (much better), and I had to turn it up to at least 5 or 6 for it to start sqealing. But, I would think that squealing shouldnt really happen at all...? (It happens even when no guitar is plugged in, but it seems to mostly only be happening on the distorted channel).

So my overall question/s is/are: What exactly is difference between the 12AX7 and SPAX7 tubes? Can/should/??? I use 12AX7's instead of SPAX7? Why is the spot with the metal shield more microphonic? I think that's it...


Question 2:

When using the effects loop, with maybe about 3 or 4 pedals (Boss DD-3 Delay, Fender Tuner, Boss OC-2 Octave, Vox Wah), I noticed a pretty bad change in tone compared to having nothing run through the effects loop. We just recently ordered a few Switchcraft 12A 1/4" inputs for that, should putting those in do the trick? Or is there some other thing to do so that there isn't such a drastic tone change (or ideally, none at all) when using the effects loop? Any and all help is greatly appreciated. Thanks!

- Mick

 

[axwielding1]

Ok, so you found the "Holy Grail" in your Dad's closet! Nice...
The SPAX7 is just a really quiet, high gain tube. You don't necessarily have to use one, but you should use the highest quality 12AX7 for sure..
I didn't like the new SPAX7, the old Sovtek ones were better IMHO.
Maybe try an EH.
As far as the loop, I don't think they are that great. At least comparing to some of the new E loops..
Watch the "pull bright" when playing loud with high treb and vol1 settings..
If it's pulled under those conditions it'll definitely scream.

Take care of that beauty, and good luck!

ax. :twisted:

 

[Boogiebabies]

 

[Elpelotero]

don't be alarmed if a strange man walks into your house at night and walks out with this...it would only be me confiscating this amp for investigation and tests...

 

[Russ]

That is not even fair....

 

[Shep]

my transformer on my mk iv has the same signature...i always thought it was a george mualler amp..it's really a Mike B...

VERY COOL AMP.lucky boy...i have a couple storys like that two...

a friend of mine's uncle who is very well off and plays alittle guitar said to him once " i got you somthing for you" M/B mk II c+ no graphic!...and said...i don't really play it any more you can have it...WTF..

another friend of mine was at a garage sale and he bought a loaded M/b mk I for $15..thats cool..

AND

another friend of mine,,,,when into a music shop a few years ago that had alot of mesa...Thats a rare thing because not alot of plp want mesa..and there in the corner was a brand new mk IIc+...the shop owner didn't know that there so good...but my friend did so he asked how much and the shop owner said " it's new and it so so old that no one want's it..it's just been seening in the shop for about 15 year's ...how does $1500 Aus sound...($1000 US) "my friends goes...i only hav $1400..lol.."lie" the guy said yes and it's a deal...under $1000US for a brand new one... !!!
thats my favorite...

Tom

 

[Boogiebabies]

 

[hans-jürgen]

Dads just suck... :wink: