Mark IIC+ - Guide for Dummies

Mark I's, II's, III's and the almight IV

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DaveP
Mark III
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Re: Mark IIC+ - Guide for Dummies

Post by DaveP » Sun Oct 18, 2009 3:14 pm

Just picked up a IIC+ with Serial 1243x. It is a simul-class, reverb, no-EQ. Received it, turned it on and saw the dreaded operational smoke.
Spoke with Mike B, he thinks it's probley just the switch that blew. I noticed one of the silver caps was ready to burst.
So needless to say it went in before I got to compare it to my 60/100. I am getting all the caps replaced and a general cleanup and inspection.
Should be good as new in a couple of weeks.
Mike confirmed the C+ status by visual inspection. Kind of cool to have of of the first ones.

igfraso
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Re: Mark IIC+ - Guide for Dummies

Post by igfraso » Sun Nov 08, 2009 11:43 am

I have just found a Mark II-C preamp block diagram in one of Mesa's old brochures.
Many people in this forum have known this for years but, being myself no electronic engineer, I thought it was worth it to share it with other rookies like me.

Lead mode has a First Gain (Input) - Tone (and Treble shift)/Volume1 - Gain makeup - Lead Drive volume - First Lead Gain - Tone shaping - Second Lead Gain - Tone shaping - Mixer Amplifier Gain - Lead Master volume - Reverb (Rev. Driver & Rev. Return Amp) - Effects Send/Return - Effects buffer gain - Master1 Volume - Graphic EQ path

Rhythm mode has a First Gain (Input) - Tone/Volume1 - Gain makeup - Rhythm Tone shaping - Mixer Amplifier Gain - Reverb (Rev. Driver & Rev. Return Amp) - Effects Send/Return - Effects buffer gain - Master1 Volume - Graphic EQ path

Maybe this information has been already posted a thousand times but I found it very useful (at least, for me) to have a block diagram like this one.
Regards
Daniel
Daniel

igfraso
Mark IV
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Re: Mark IIC+ - Guide for Dummies

Post by igfraso » Sat Nov 28, 2009 1:53 pm

By request, I scanned the block diagram so you can find it here below.

Image

Boogiebabies, I know you will immediately realize that the preamp tubes names (V1A; V1B; etc) don't match the ones stated in the Maintenance & Repairs manual. I have no idea why.

Best regards
Daniel

chipaudette
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Re: Mark IIC+ - Guide for Dummies

Post by chipaudette » Mon Nov 30, 2009 3:29 pm

To my eye, this is the flow diagram for the IIC+ not the IIC. Note how the effects loop comes after the lead circuit.

I believe that in the IIC, the effects loop comes before the lead circuit. The position of the effects loop relative to the lead circuit is why the lauded "loop test" is able to differentiate a IIC from a IIC+. To my eye, the circuit as drawn would "pass" the loop test, making it a IIC+.

I do see that the diagram says "IIC" at the top, but did Mesa differentiate its documentation between IIC and IIC+ at the time?

Chip

igfraso
Mark IV
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Re: Mark IIC+ - Guide for Dummies

Post by igfraso » Mon Nov 30, 2009 7:15 pm

Regarding the documentation differentiation, in a 2005 Mesa brochure, Randall Smith was promoting the Mark IV as:
"Voted amp of the year three times in Europe and still one of our most popular models, includes fabled II-C Lead sound."

This was 2005... so it seems Mesa was trying to downplay the difference between the C and C+ (even 20 years after they stopped producing the II-C+) and refusing to give the C+ its own identity.

Maybe in RCS mind, the II-C and the II-C+ are essentially the same amp. We can only suspect that, had he designed the C+ himself, he would have called it the II-D.

Just guessing... but this could be the reason why an apparently II-C+ diagram says II-C at the top.
Regards
Daniel

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Boogiebabies
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Re: Mark IIC+ - Guide for Dummies

Post by Boogiebabies » Wed Dec 02, 2009 2:34 pm

I consider all the amps to be a IIC with or without a "+" modification.

Great score on the block diagram. :D

mikebu
Mark I
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Re: Mark IIC+ - Guide for Dummies

Post by mikebu » Wed Dec 23, 2009 3:49 pm

I bought my Mark IIC+ with a 13xxx serial number directly from Mesa. At the time I don't recall anyone from Mesa actually telling me I was getting a C+. For years I just thought I had a Mark IIC. It wasn't until I pulled it out of the basement after not playing much the last 10 years and doing some web searches and finding out there was a C and a C+ and I had a C+. None of the papers that came with the amp said C+ either.

My amp is getting delivered today after getting a once over from MikeB at the Mesa factory. Can't wait to play with it. I have been playing my son's Line6 Spyder IV that I bought for him. Then in 2 weeks or so my 83 Les Paul Custom should be ready to play. A local shop is taking off the Kahler bar I foolishly put on.
1984 Gibson Les Paul Custom
2010 Fender American Standard Stratocaster
2011 Music Man Axis Tribute
2011 Fender 60th Anniversary Telecaster
Mesa Boogie Mark IIC+ SRG Combo
Fender Blues Junior

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nocluejimbo
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Re: Mark IIC+ - Guide for Dummies

Post by nocluejimbo » Sun Aug 01, 2010 4:31 pm

I have a Mark II. which I believe to be a IIC, but the serial number is in the 38** range. As in, almost 10,000 short of where a IIC should lie.

It has all of the specifications to match a IIC -

HRGX chassis code / export tranny / 100/60 switch
Pull Shift on Bass
Pull Gain Boost on Master 1
Effects loop on back, as opposed to Preamp out/Power amp in


And it doesn't appear as though there have ever been any modifications... if there were, they were DEFINITELY by Boogie and at least have been since the 80's since they were done. What's the deal with my amp?

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lesterpaul
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Re: Mark IIC+ - Guide for Dummies

Post by lesterpaul » Sun Aug 01, 2010 9:00 pm

nocluejimbo wrote:I have a Mark II. which I believe to be a IIC, but the serial number is in the 38** range. As in, almost 10,000 short of where a IIC should lie.

It has all of the specifications to match a IIC -

HRGX chassis code / export tranny / 100/60 switch
Pull Shift on Bass
Pull Gain Boost on Master 1
Effects loop on back, as opposed to Preamp out/Power amp in


And it doesn't appear as though there have ever been any modifications... if there were, they were DEFINITELY by Boogie and at least have been since the 80's since they were done. What's the deal with my amp?
http://homepage.mac.com/mesaboogie/serials.html
try this....
"major scales...whats that??"-Doug Aldrich
C+ DRG,B+DGX,C+KRG(Twocious Maximus)
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nocluejimbo
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Re: Mark IIC+ - Guide for Dummies

Post by nocluejimbo » Sun Aug 01, 2010 9:29 pm

lesterpaul wrote:
nocluejimbo wrote:I have a Mark II. which I believe to be a IIC, but the serial number is in the 38** range. As in, almost 10,000 short of where a IIC should lie.

It has all of the specifications to match a IIC -

HRGX chassis code / export tranny / 100/60 switch
Pull Shift on Bass
Pull Gain Boost on Master 1
Effects loop on back, as opposed to Preamp out/Power amp in


And it doesn't appear as though there have ever been any modifications... if there were, they were DEFINITELY by Boogie and at least have been since the 80's since they were done. What's the deal with my amp?
http://homepage.mac.com/mesaboogie/serials.html

try this....
Yeah, I have seen that chart before... except this amp bears absolutely NO resemblance to a IIA except for the low serial.

JOEY B.
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Re: Mark IIC+ - Guide for Dummies

Post by JOEY B. » Mon Aug 02, 2010 5:52 am

nocluejimbo wrote:Yeah, I have seen that chart before... except this amp bears absolutely NO resemblance to a IIA except for the low serial.
If you look about 1/3 the way down on page 4 of this thread, you will see that Frank(dodger916) has a IIA>IIC+ upgraded amp. Yours could be something like his.
"One of these days, I'm gonna change my evil ways....... one of these days.

igfraso
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Re: Mark IIC+ - Guide for Dummies

Post by igfraso » Mon Aug 02, 2010 10:16 am

nocluejimbo wrote:I have a Mark II. which I believe to be a IIC, but the serial number is in the 38** range. As in, almost 10,000 short of where a IIC should lie.
As Joey B. says, it could be one of the few upgraded II-A.
By the way, what date does it have inside the chassis?
Daniel

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nocluejimbo
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Re: Mark IIC+ - Guide for Dummies

Post by nocluejimbo » Mon Aug 02, 2010 12:21 pm

JOEY B. wrote:
nocluejimbo wrote:Yeah, I have seen that chart before... except this amp bears absolutely NO resemblance to a IIA except for the low serial.
If you look about 1/3 the way down on page 4 of this thread, you will see that Frank(dodger916) has a IIA>IIC+ upgraded amp. Yours could be something like his.
Interesting...

I supposed this could have been the case, but have never actually seen another example of such.
igfraso wrote:
nocluejimbo wrote:I have a Mark II. which I believe to be a IIC, but the serial number is in the 38** range. As in, almost 10,000 short of where a IIC should lie.
As Joey B. says, it could be one of the few upgraded II-A.
By the way, what date does it have inside the chassis?
I don't know where to find the date inside the chassis?

JOEY B.
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Re: Mark IIC+ - Guide for Dummies

Post by JOEY B. » Mon Aug 02, 2010 8:39 pm

nocluejimbo wrote:I don't know where to find the date inside the chassis?
The upgrades that I have seen will have something like IIB>IIC+ written on the upper edge of the chassis to the left or right. The preamp circuit board revision is also a dead giveaway. It will be located at the far right of the preamp board when viewing from the rear of the chassis. Have you tried the C+ loop test?
"One of these days, I'm gonna change my evil ways....... one of these days.

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av8or3
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Re: Mark IIC+ - Guide for Dummies

Post by av8or3 » Sat Aug 28, 2010 1:46 am

FWIW, a 100 watt C+ sold recently on e-bay had the
serial number 14,387. That's the closest one I've seen
to the end of the line. It was a DRGX.
Nice amp too......
See 'ya,
Jim
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MK IIB HRG Short Headshell & EVM Thieles by GTS

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