Mesa Boogie Mark III Simul-Class modded to be non simul

Pre Recto days. Boogie modified Fenders, Mark I-IV, Dual Calibers, etc

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Jordan1990
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Joined: Mon Feb 22, 2016 12:56 pm

Mesa Boogie Mark III Simul-Class modded to be non simul

Post by Jordan1990 » Mon Feb 22, 2016 1:02 pm

Hello all this is my first post to the board, I've just ordered my first mesa and I'm stoked. It's a red stripe "simulclass" that the techs at mesa say has been modded to a non simul. My question is why and how? I called mike at mesa to see about it getting switched back but could I benifit more from this?
Mesa Boogie Mark III Red Stripe
Roland Jc-120
Epiphone Explorer 84 Reissue (Alpine White)+(Ebony)
ESP LTD EXP 200 (Satin Grey)
BOSS BF-3, NS-2, TU-3, PS-6 Ch-1
MXR Phase 90, Phase 100
Tubescreamer TS808
EHX Switchblade

Jordan1990
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Joined: Mon Feb 22, 2016 12:56 pm

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by Jordan1990 » Mon Feb 22, 2016 1:03 pm

I'm waiting on Mikes call back but would like to hear from you guys
Mesa Boogie Mark III Red Stripe
Roland Jc-120
Epiphone Explorer 84 Reissue (Alpine White)+(Ebony)
ESP LTD EXP 200 (Satin Grey)
BOSS BF-3, NS-2, TU-3, PS-6 Ch-1
MXR Phase 90, Phase 100
Tubescreamer TS808
EHX Switchblade

sotosprince
Mark III
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Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by sotosprince » Tue Feb 23, 2016 4:38 am

Welcome to the board man! I am Sotiris aka #ios4ever# ;)

BlackBoxy
Mark III
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Location: France

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by BlackBoxy » Tue Feb 23, 2016 11:21 am

easy to get Simulclass , just add or reconnect central tubes pin 8 to switch open/ground

Jordan1990
Bottle Rocket
Posts: 19
Joined: Mon Feb 22, 2016 12:56 pm

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by Jordan1990 » Tue Feb 23, 2016 5:48 pm

sotosprince wrote:Welcome to the board man! I am Sotiris aka #ios4ever# ;)
thanks man I've saw ya here a time or two.
BlackBoxy wrote:easy to get Simulclass , just add or reconnect central tubes pin 8 to switch open/ground

And that's it? What if the hacked the transformer out? I shpuld have it in my possession in 3 or 4 days so I'm not sure what has happened to it
Mesa Boogie Mark III Red Stripe
Roland Jc-120
Epiphone Explorer 84 Reissue (Alpine White)+(Ebony)
ESP LTD EXP 200 (Satin Grey)
BOSS BF-3, NS-2, TU-3, PS-6 Ch-1
MXR Phase 90, Phase 100
Tubescreamer TS808
EHX Switchblade

JOEY B.
Dual Recto
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Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by JOEY B. » Tue Feb 23, 2016 7:05 pm

To truly change from a Simulclass to a 60/100, a different output transformer is used, I believe.
"One of these days, I'm gonna change my evil ways....... one of these days.

Jordan1990
Bottle Rocket
Posts: 19
Joined: Mon Feb 22, 2016 12:56 pm

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by Jordan1990 » Wed Feb 24, 2016 12:31 am

Mesa called and left a voicemail saying if a amp was born there simul class and switch over here"I hope" and to be switched back here "I hope" then yes it can be done. Those are the exact words. I'm going to call him back tomorrow. But yes I would think that too about the transformer but mesa acted like it was a quick easy change. I hope easy enough for me to do cause thats cutting my cab funds all up Lola. Thanks guys!!
Mesa Boogie Mark III Red Stripe
Roland Jc-120
Epiphone Explorer 84 Reissue (Alpine White)+(Ebony)
ESP LTD EXP 200 (Satin Grey)
BOSS BF-3, NS-2, TU-3, PS-6 Ch-1
MXR Phase 90, Phase 100
Tubescreamer TS808
EHX Switchblade

BlackBoxy
Mark III
Posts: 229
Joined: Thu Oct 04, 2012 6:14 am
Location: France

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by BlackBoxy » Wed Feb 24, 2016 5:28 am

JOEY B. wrote:To truly change from a Simulclass to a 60/100, a different output transformer is used, I believe.
nope,

its the same OT , and as all Mark III are 4 amp tubes powered as simul class, it can easily be revesed to class A/simul class , i don't see what are advantages to mod a class A to permanent simulclass , OT delta voltage is around 5 volt between both pairs of tubes output!

stokes
Single Recto
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Location: NYC

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by stokes » Wed Feb 24, 2016 8:34 am

Simul class uses an "ultra-linear" OT,that has seperate taps that would be for the screens in a 2 tube output.These taps are used for the plates of the inner pair of tubes for simul class.Delivers a couple less volts to the inner pair.

BlackBoxy
Mark III
Posts: 229
Joined: Thu Oct 04, 2012 6:14 am
Location: France

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by BlackBoxy » Wed Feb 24, 2016 2:07 pm

stokes wrote:Simul class uses an "ultra-linear" OT,that has seperate taps that would be for the screens in a 2 tube output.These taps are used for the plates of the inner pair of tubes for simul class.Delivers a couple less volts to the inner pair.

an ultra linear OT coil? what is that ?

stokes
Single Recto
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Location: NYC

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by stokes » Wed Feb 24, 2016 4:20 pm

Look at the schem for a simul class.You will see a winding tap on each side just short of the plate tap at the end of the winding.Before Mesa came up with their simul class scheme these transformers were used as "ultra linear output trannies".That extra tap was connected to the screen of the output tube on that side,with the longer tap connected to the plate.It delivered a few volts less to the screens.In simul,Mesa uses these taps for the inner set of tubes plates.

Jordan1990
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Posts: 19
Joined: Mon Feb 22, 2016 12:56 pm

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by Jordan1990 » Wed Feb 24, 2016 8:08 pm

Well you all have lost me lol. I'll wait and see what transformer it has and try to get pics up. I'm doing this on a phone so I'm not sure if I can. Thanks guys

Jordan
Mesa Boogie Mark III Red Stripe
Roland Jc-120
Epiphone Explorer 84 Reissue (Alpine White)+(Ebony)
ESP LTD EXP 200 (Satin Grey)
BOSS BF-3, NS-2, TU-3, PS-6 Ch-1
MXR Phase 90, Phase 100
Tubescreamer TS808
EHX Switchblade

BlackBoxy
Mark III
Posts: 229
Joined: Thu Oct 04, 2012 6:14 am
Location: France

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by BlackBoxy » Fri Feb 26, 2016 7:28 am

stokes wrote:Look at the schem for a simul class.You will see a winding tap on each side just short of the plate tap at the end of the winding.Before Mesa came up with their simul class scheme these transformers were used as "ultra linear output trannies".That extra tap was connected to the screen of the output tube on that side,with the longer tap connected to the plate.It delivered a few volts less to the screens.In simul,Mesa uses these taps for the inner set of tubes plates.

thanx alot, i know about the taps, schematics are clear on this, it was just the linearity of a a signal through a solenoid .

regards
Last edited by BlackBoxy on Fri Feb 26, 2016 7:32 am, edited 1 time in total.

BlackBoxy
Mark III
Posts: 229
Joined: Thu Oct 04, 2012 6:14 am
Location: France

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by BlackBoxy » Fri Feb 26, 2016 7:31 am

Jordan1990 wrote:Well you all have lost me lol. I'll wait and see what transformer it has and try to get pics up. I'm doing this on a phone so I'm not sure if I can. Thanks guys

Jordan

you do think they changed the OT ? so yes it could be problematic

stokes
Single Recto
Posts: 1459
Joined: Sun Feb 19, 2006 11:43 am
Location: NYC

Re: Mesa Boogie Mark III Simul-Class modded to be non simul

Post by stokes » Fri Feb 26, 2016 10:18 am

The transformer is the key ingredient in simul,but it doesnt mean the transformer was changed.A simple re-wire of the plate taps may be all they've done.The switch on the cathodes of the inner tubes isnt so much a simul switch as it is a "class A" switch.In order to have simul you need 4 power tubes connected,in these amps there is no way to have 4 powertubes active without being in simul.......except to re-wire the plate connections or change the tranny.If the tranny is not blown,I can see no reason to change out the tranny,so it is likely someone did the simple mod.

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