Mesa Mark iic+ long head - 60/100 or Simul-class?

[CaptainCrunch]

Need some help. I am not familiar with the iic+ long heads and am trying to figure out whether this is a simul or 60/100 for sure.

I have attached pics for referece.

You can see:

1 - transformer says simul-class on it
2 - I can't see an class A/B switch on back
3- looks like it has all 6L6s in it but the matched pairs are in wrong spots (should be 2 inner and 2 outer matched)
4- front has 1/2 power switch? could be class a/b?

thx

 

[jlbaxe]

its the half power switch on the front. use to be in the back on the vol side.

 

[jlbaxe]

6L6 and EL34s

 

[glip22]

It's a Simul-Class

 

[steve_k]

Be careful with this amp. Someone has the power tubes paired wrong. Mesa used the same transformers for SC or non-SC. Normally, the II's would have a SC switch on the back right of the chassis to allow you to mix 6L6/34's as Inner/Outer pairs Unless the amp has been hard wired for the tube layout and SC, I would say it is not. These came as 100/60 or SC.

 

[cardinal]

I believe the long heads all say full/half power, but that definitely has the Simul OT. Since they're all 6L6 tubes in there, probably OK, but yeah, a silly way to install the tube pairs.

BTW, whoever bought this bought it for a song from GC very recently. Not that it really matters, but on principle I wouldn't be willing to pay a king's ransom for it because of that.

 

[Mesa\Kramer]

Look at the pics in this listing


https://www.ebay.com/itm/like/231138623380?lpid=82

 

[H3000]

one way to find out for certain is to get a bias meter and take a reading off all the tube sockets
if it is a non simul class version then all tubes will pull the same current draw but if it is a simul class then you will see different readings on the class a tube sockets

 

[CaptainCrunch]

do the full head shell simuls come with the class a/b switch on the back or no? I have a short head simul ic++ and it has the switch but I looked at some online googles and looks like some don't. I've never tried but can the simuls take all 6l6s as well? i know they take the 2 inner then two outer 6l6 and el34 just not sure if im looking at this one and it has 4 6l6s, can it still be a simul (unless hard wired)

 

[dsquared]

Long head will have switch on front, med/short on back as Steve said.

Simul can take all 6L6s just fine. It is the default.

 

[CaptainCrunch]

so there's no switch on the front or back for class a/b and even though it's a simul transformer they came in both 60/100s and simuls? don't the 60/100s have that switch as well (100rms or 60) that I don't see on this either

 

[4406cuda]

I have a Mark III long head and it is a simulclass.

The switch is on the front and it is labeled Half Power.

 

[CaptainCrunch]

I have a Mark III long head and it is a simulclass.

The switch is on the front and it is labeled Half Power.

how do you switch between all 6l6s and 6l6 and el34s with no switch and how can u tell its a simul class

 

[Anonymous]

Call Mesa for a definitive answer.

I think its not a simul if it has a half power switch. Sure, it has the right x-former but that doesn't mean its wired for simul operation. Have you auditioned the two settings? If its simul, in the class A setting, the volume will go WAY down to a 15 watt sound. It will sound very different (sweeter!) from full power. If its the half power option the volume won't go down that much and it will stay pretty much just a smaller version of the full power sound.

 

[cardinal]

Dude relax. Long heads have the switch upfront not on the back. That transformer is a simul tranny.

 

[4406cuda]

I have a Mark III long head and it is a simulclass.

The switch is on the front and it is labeled Half Power.

how do you switch between all 6l6s and 6l6 and el34s with no switch and how can u tell its a simul class

You do not need a switch to go from all 6l6s and 6l6 and el34s

Mine has a simulclass sticker/decal on the back.

There is a ton of info about Mesa Boogie products on the Boogie Board

http://www.grailtone.com

 

[mojotone]

Simulclass output transformer = simulclass power tube wiring.

In this amp "Half Power" = Class A switch on the short head's rear switch.

Tube this amp EL-34,6L6,6L6,EL-34, and the Half Power mode will be just the EL-34's at 15 watts.

If you are still not convinced, pull power tubes 1 and 4, then look for a resistor going across the tube socket where the tube alignment pin fits into the socket. It can be seen with a mirror and a flashlight, if you know what you are doing.

 

[thiswaythatway]

On another note, I noticed one of my EL34's wasn't lighting up, no heat from it at all either but the amp was working fine in either Class A or simul. Installed a new set of 6L6's and all is well. I thought the amp would fail with a dead power tube?

 

[mojotone]

I had a broken solder joint at pin#2 (best I can remember) that would render the tube cold, but not blow a fuse. Good luck!