Cab compatible ?

[mark2boogie]

Hi all,

Sorry for that "newbie-boogie" question - I did not find a direct answer on the forum :

Are the MKI, IIA, IIB, IIC, III, IV COMBO 1x12" amp chassis of the exact same dimensions ?

I mean : are they interchangeable ?

For example, would a MKIIA 1x12" combo amp chassis enter a 1x12" MKIII hardwood combo cab ?

Thanks for answer,

A+!

 

[MrMarkIII]

The Mark III "short" chassis (17 inches), center to center between the chassis mounting screws:

Front to back: 5 3/8 inches.
(This is dimension #5 in mark2boogie's post below)

Side to side: 15 3/4 inches.
(This is dimension #2 below)

The two mounting holes closest to the rear of the cab are 2 3/8 inches from screw center to the edge of the rear of the cabinet.
(This is dimension #4 below)

All other dimensions are derived from these.
The above dimensions apply ONLY to the 17" Mark III chassis.
If your chassis has more than seven knobs on the front panel,
you do not have a 17" chassis.
If your chassis has more than three toggle switches on the front panel,
you do not have a 17" chassis.
If you have a toggle switch on the front panel labeled "FULL / HALF POWER",
it's the Simul-Class switch 99.999% of the time.

The name for "cup-mounted" is "SUS-4".

All measurements are the same for combo, head cab, tolex, hardwood.

If your head cab has a large, unoccupied cut-out in the bottom, you're missing the reverb tank - that's where it goes on a head cab.
If you are replacing a reverb tank on a head cab, they are different (open side UP), compared to the tank in a combo cab (open side DOWN).

Hope this helps.

 

[mark2boogie]

Hi MrMarkIII & thanks for this useful information for the MKIII side !

I will try to collect the same info about the MKIIA - as mine isn't already at home... And I found a nice MKIII wooden cab to buy !

A+!

 

[mark2boogie]

Hi all again,

Let's go for optimun accuracy...

If any of you can give me like MrMarkIII the position of the mounting screws on their MKIIA and MKIII combos (other MK combos are interesting, of course), it would be of a great help - not only for me, I think...

The dimensions are labelled 1 - 2 - 3 - 4 - 5 - 6 on the cabinet upper view schematic below. You can give me the values in inches or mm, along with your amp's model and year, cup mounted chassis or not, both are of interest.

Thanks !

A+!

 

[dodger916]

The mounting hole spacing on the IIA (and Mark I) differ from later Mark versions.

 

[mark2boogie]

The mounting hole spacing on the IIA (and Mark I) differ from later Mark versions.

Hi dodger916 & Thanks - I read the same advice as yours somewhere.

But what I want to know is how much is the difference, and having details about that, in order to see if a slight adaptation is possible by myself.

A+!

 

[dodger916]

The hole spacings are 16 5/16" side-to-side (width); 5 7/16" front-to-rear.

The mounting hole spacing on the IIA (and Mark I) differ from later Mark versions.

Hi dodger916 & Thanks - I read the same advice as yours somewhere.

But what I want to know is how much is the difference, and having details about that, in order to see if a slight adaptation is possible by myself.

A+!

 

[DaveP]

Also a reissue Mark I cabinet will fit the Mark II-IV chassis hole spacing. When Mesa re-issued the Mark 1 they didn't revert back to the old chassis hole spacings
they stayed with the new.

 

[mark2boogie]

When Mesa re-issued the Mark 1 they didn't revert back to the old chassis hole spacings
they stayed with the new.

it seems to be right : the MKI RI will be compatible with the MKIII and after, and with most of the MKIIB - those which uses the SUS4 mounting system.

I think that Mesa changed the spacing to accomodate the SUS4 system, otherwise the screws would have been too close to the sidewalls of the cab - I do not have the detail of the SUS4 system, but I imagine that it is a justification of the change in spacing since this system is probably bigger due to the shock mount inlays.

To sum up what I have found and measured ( dimensions 2 and 5 on my previous post schematic) :

- Old Style Spacing, NO SUS4 = MKI, MKIIA = 416mm x 135mm

- New Style Spacing, WITH SUS4 = MKIIB, MKIII, etc... = 400mm x 135mm

It also seems that the change is not as bold as the MKIIA to B transition.

I really thought that many of you (non-newbie) would have known these informations !

A+!

 

[mark2boogie]

OK - Thanks to an old post from a member (shakti) I know now that I can make a SUS4 cab compatible with a non-SUS4 chassis.

So here's the hardwood cab I bought - it is reputed to have housed a MKIIB or C (?) :

Can you tell me from which wood it is made ?

Do you think it's really an original one ?

What do you do to care the wood (cleaning, cure for the light scratches, etc...) ?

Thanks for your advices !

A+!