Question for Mark IIA owners/players

[dodger916]

Greetings.

I recently demod a IIA and was pleasantly surprised at how Channel 1 had a mild but definite crunch with Vol 1 at 10. Is this typical of IIAs or unique to this amp? My IICs definitely don't do this.

Thanks in advance.

Frank

 

[dodger916]

bump. No Mark IIA guys out there?

 

[JimmyB]

Sorry... saw your original post earlier in the week, but got sidetracked!

With Vol 1 at 10, using moderate output P90s or humbuckers, there's a bit of hair on the cleans and some drive when really digging in, but I wouldn't put in 'crunch' territory.

Now, with 'Gain Boost' pulled and Vol 1 on 10, well... that's a big, fat, woolly tone that puts a Mk I to shame! :lol: :mrgreen:

 

[dodger916]

Sorry... saw your original post earlier in the week, but got sidetracked!

With Vol 1 at 10, using moderate output P90s or humbuckers, there's a bit of hair on the cleans and some drive when really digging in, but I wouldn't put in 'crunch' territory.

Now, with 'Gain Boost' pulled and Vol 1 on 10, well... that's a big, fat, woolly tone that puts a Mk I to shame! :lol: :mrgreen:

That's what I'm talking about! Yes, the Gain Boost was pulled and it was one of the best rhythm tones I've ever heard. Raucous but tight. Thanks for the response.

 

[igfraso]

Dodger916,

The Mark II-A has a very unique sound and, especially, on the clean channel.

According to Mike Bendinelli, it is very much like a tweed Bassman and like the typical Jerry Garcia sound. He also said that you won't find the II-A sound in any other Mark series amp.

I also recall that there was an interview to Randall Smith (you can find it in the Mesa Boogie site) where he was asked who came in first: himself with the Mark II-A or Dumble with his amp. He replied that both of them were working on similar designs with no knowledge of what the other one was doing.

In Randall Smith's own words... "As far as Dumble, I don't know much. I've never been inside of one of his amps, although I hear they're all gooped up to prevent copying and that they are built on printed circuit boards. I did run across a hand-drawn block diagram somewhere — I don't know — Gerald Weber's book or Aspen's — of an Overdrive Special and it looked to me like the functional equivalent of a Mark II. The configuration was the same, deriving the overdrive the same way, had the controls and internal switches in the same locations and so on. Howard no doubt has his own ways of doing things and makes great amps, so many of the parts values and such could be different, or the whole thing could be different for all I know. Really, my only exposure to his amps is that one block diagram, although I did meet him briefly in 1973 or'74."

Maybe I am wrong but I read that:
- the BF Fender vibrato channel and the Mark I input 2 channel have a First Gain-Tone/Volume-Gain makeup-Gain-Reverb path
- the Mark I input 1 channel has a Extra First Gain- First Gain-Tone/Volume-Gain makeup-Gain-Reverb path
- the Marks II, III and IV in lead mode (and the Dumble?) have added a fifth gain stage and a fourth volume control in the signal path.

Disclaimer: I am in no way an electronic engineer/technician so I am eager to read the opinion from the experts here.
Best regards
Daniel

 

[Boogiebabies]

It looks like a guitar is chord hanging out of the bottom jack. That's input 2 on a MK I.
The EQ is one of the greatest assets to the Mark series. It helps enormously with outdoor EQ'ing.
Those setting would also make it louder, especially with the 750 full up. It may have help drown Jerry out
if he was on a bender... :mrgreen:

 

[dodger916]

So I did hear something special, and it wasn't necessarily a faulty amp. I'll have to play it again.