My C+ inside & out photos

[funk49]

Ok guys, I'm posting photos of my 1984 C+ for review. If anyone has any opinions on whether it's been modded or messed with, I would really appreciate it. I've owned it since 1990, where I bought it from a store that really placed no significant importance on it. I guess back then, there wasn't as much of a big deal on them. I'm not sure of the history, but it was having issues when they got it and made some repairs. This has to be the best amp I've ever heard in my life. Unbelieveable tone from this monster...it just absolutely sings. I played this amp for 10 seconds in the store when I knew I had to have it...the headroom was like no other I had ever encountered.

Anyways, it's a fully loaded (Simul, EQ, reverb) long chassis head, a rare one of the Holy Grails. I've been told by Bendo that they made around 150 of these, this one being created on 6/84.

Thanks for the feedback or whatever you guys can provide.

--Rob



Inside left
Inside 1
Inside 2
Trans 1
Inside left 3
Inside right 1
Inside TR 1
Outside back
Outside back left
Choke
Front 1
Front 2
Trans 2

 

[908ssp]

I'm no expert but the insides look very clean unmolested. My amps are both short chassis the long chassis does leave some room and makes a neater more user friendly layout. I bet it sounds awesome.

 

[Boogiebabies]

100% FACTORY IIC+ with Simul, EQ, Reverb and the long chassis.
The serial number fits and it was an early long chassis due to the "Gain Boost" Faceplate. It is not like the modded ones with serial numbers below 12500, it is a real one. The 150K plate load resistor off the main 30uf 500V cap on the main preamp board has been changed. There have been two changed screen grid resistors on the 6L6's. It has also had the brightness reduction .001 mod to the V4A ( lead channel). I cannot tell if it has had the 10pf mod to the clean channel due to the angle. Other than that, all the resistors and black tantalum cathode caps are original. The silver hermetically sealed cathode caps are stock as well, including the .22uf pull bright on the V4A. All original filter caps as well, including the bias supply caps.

Looks like a real IIC+ with a few minimal repairs and mods. Nice 105 Transformer too !!!


I would pull the front head cover off and remove the fan for cleaning. It slides out the front. The dust is going to kill it and dry up the dielectric and you will have a noisy or going dead or dead fan. You cannot get those Cyclohms anywhere.


Ed

 

[funk49]

Damn Ed, you really know these amps. Simply amazing! I think the lionshare of the repairs were actually done in Hollywood about 3 months ago when I took it in for servicing. The gain stage was crapping out, not sounding too thin or anything, just getting noisy, unlike anything I've heard from the amp, almost like a preamp tube but not quite.

Hollywood replaced some tubes and some resistors, but I didn't think they did 6L6 resistors. Do the grid resistors look pretty current? I'll have to go back and look at the docs to see what they did? I'm also suprised that it has the brightness reduction mod because I never had it done. The only time it's ever been in for repair was this last time.

The amp definitely doesn't sound bright, that's for sure. Obviously, the mod takes care of that. I'm running this amp through 2 road ready series cabs that are fully loaded with the Black Shadow EV's and it just ROCKS. I can't play this amp past 2.5 in any band setting. My buddy runs his red stripe at 3 and 4...I could never make to that point. I would be fired instantly as people already think I have a volume problem!

Thanks again for the analysis! I really appreciate it. I just need to figure out a way to blend this amp in with my other amp, the Guytron GT-100.

 

[Boogiebabies]

The screen grid resistors are the Two big black ones that say " Mexico" on them and go to pin 3 on the inner sockets (6L6). These are what Mesa currently uses. They originally would have looked like the the large brown 470ohm on the EL34 sockets. The bright mod looks old. It may have been done by mistake? The silicone is very yellowed. If it were recent it would be clean and clear. So Mesa changed a few resistors for noise and maintnance. No biggie. The 150K off the 30uf feeds the V1 plate load resistors. Carbon film resistors can get noisy.

The only strange thing I see on this amps is that you have no pin #8 on any of the power tube sockets or a trace to them. It is an early version of the Mesa 7C1 power board. Later boards had pin 8 to ground. I can also assume that the Master Volume pot was replaced as it has the 22K series resistor and it wired to the PCB instead of being wired directly to the cap.
This is the brown wire to the 22K resistor off the master pot. This was due to CTS's production of these pots being switched from the USA to Taiwan. The taper was so inconsistent that Mesa added the 22K to calm the taper. Thus, this amp may seem to be very loud even at 2.5. The original pot was less agressive and would actually allow you to taper to a wopping 4 before the windows blew out.

A very nice amp and a very uncommon loaded long chassis.

 

[funk49]

Wow, thanks again for the detailed analysis of my amp! It's nice to know what's going on inside as I'm not an engineer. I just enjoy the insane tonal qualities of this particular amp.

I'm taking a trip up to Petaluma to meet up with Mike in about a month and am taking this along to have him look at while I'm there. Maybe there's something that he can recommend or suggest, although to my ear, it doesn't need anything. I might possibly try to get some old original caps (hopefully he has some stashed someplace) to replace the Mexican ones they put in as I want this thing stock as possible.

 

[BPski]

According to the photos the pin in Question is Pin #1, not pin #8. This pin is actually not even there. There is a small PCB trace near where pin #1 would be that does not go anywhere. If this were pin #8 with no connection the amp would not work, it is the Cathode.

Hope this info clears things up.

 

[Boogiebabies]

You are right. Sorry for the mistake your greatness. A quick glance at a picture at work. Fifty lashes.


If you guys know so much then I am not needed. Take pleasure in jumping on other peoples mistakes.


Best of luck guys. I am out. I just cannot take the know-it-all's who ask goofy retorical questions then banter about the answer as if they knew it in the first place. i thought this place was going to be different.

If you can find a guy who knows more about the MK IIC+ circuit, then you can yank him off and belittle him.

Figure it out yourself.


Funk,

PM me if you get a chance.

 

[Boogiebabies]

Vote for Pedro !!!


Funk,

Pin 1 and 8 should be connected per Mike B's suggestion on the EL34 sockets. The trace, now that I have looked at all three of mine off pin 1 goes nowhere. I jumped pin 1 and 8 on all three, just like a typical EL34 setup.

 

[MesieBooga]

You are right. Sorry for the mistake your greatness. A quick glance at a picture at work. Fifty lashes.


If you guys know so much then I am not needed. Take pleasure in jumping on other peoples mistakes.


Best of luck guys. I am out. I just cannot take the know-it-all's who ask goofy retorical questions then banter about the answer as if they knew it in the first place. i thought this place was going to be different.

If you can find a guy who knows more about the MK IIC+ circuit, then you can yank him off and belittle him.

Figure it out yourself.


Funk,

PM me if you get a chance.

Boogie;
We appreciate you here on the board!

 

[Boogiebabies]

You are right. Sorry for the mistake your greatness. A quick glance at a picture at work. Fifty lashes.


If you guys know so much then I am not needed. Take pleasure in jumping on other peoples mistakes.


Best of luck guys. I am out. I just cannot take the know-it-all's who ask goofy retorical questions then banter about the answer as if they knew it in the first place. i thought this place was going to be different.

If you can find a guy who knows more about the MK IIC+ circuit, then you can yank him off and belittle him.



Figure it out yourself.


Funk,

PM me if you get a chance.

Boogie;
We appreciate you here on the board!

Thanks,

It just pisses me off when a DB like that goes trolling.

I will help my buds out, always. The Mesa faithful and the newbies with valid questions on these superb amps. I have spend hours on the phone with Mike B. and three years studying the evolution of the IIC+ circuit as my main hobby. I have examples of early, mid and late models. Mike B. has also been more than generous with his time and mods. It is my favorite pastime. I have spent as much tme as humanly possible to not give wrong information. If I learn something from one of you guys, I appreciate more than you know, but when someone give bad info, I dont piss in his cheerios. That was like the old board. I will just be more selective here. If you want to know about a IIC+ mod, call Mesa and then send the $250.00.

Ed

 

[BPski]

I did not mean to cause any upset. I just wanted the fellow that asked the question to have the right info. I thought I was helping a guy out a little. Anyone can make a goof-up and I thought that as a "community" we'd all help each other.

I may be a newbie to the Board but my experience as a tech I thought would be in some way helpful here to the community.

No worries.

 

[funk49]

wow...what a real bummer. We would hate to see you bail from the boards, Boogiebabies. Besides, if we don't have you here to answer questions, Mike's job will be reduced to 8 hours a day of C+ questions.

He told me that he spent 4 hours the other day taking calls about these...I'm sure his time can be MUCH better spent working on other things !

Anyways, BB, hope you stay. Your knowledge is really useful and appreciated.

--Rob

 

[MesieBooga]

Mike should be on this board too! 8)

 

[funk49]

He might save alot of time in the shop on the phone by answering a few questions here, but he has said in the past that he's not a big fan of computers, so it most likely wouldn't happen. Definitely seems to be an "old school" type of guy, but one of the nicest people in the business by far.

I think some of his good vibes rubbed off on the C+'s!

If anyone needs great slipcovers for amps and other things, make sure to check out his wife's business, http://studioslips.com/. They make excellent slip covers and you're supporting the Bendinelli's! What can be better than that?

 

[Boogiebabies]

Mike B. told me all the tricks and mods. Why? Were on the same page without looking at the amp.

 

[MesieBooga]

If anyone needs great slipcovers for amps and other things, make sure to check out his wife's business, http://studioslips.com/. They make excellent slip covers and you're supporting the Bendinelli's! What can be better than that?

Great to know. I've spent a fortune on TUKI covers.... if I had known!