Mark III Tech Question (C+ Mod)

[#2121313]

Kind of a double question here, would a) a Mark III (not sure if the stripe will matter, but it's a red stripe amp) pass the C+ loop test, or "should" it pass the C+ loop test. And b) would a Mark III that has the C+ mod, so a III+, would or should that amp pass the C+ loop test?

Reason I ask, I just picked up a Mark III Red Stripe and am really diggin' the tone. It seems very noticeably different than the blue stripe I once owned (both were simul long chassis heads). So out of curiosity, I thought I'd try the C+ loop test, and when I plug my guitar into the return jack of the loop there is no affect when I turn the drive or volume knob.

Not sure if this meant anything in terms of whether the amp ever had the C+ mod done?

I'm no tech so looking under the hood is of no use to me, but lemme post some pictures anyway...pics to come.

 

[>Photi G<]

A stock Mark III will pass the loop test. This is because it comes stock with the updated FX circuitry that the C+ touted. So, the only way to tell if the III+ mod was done is to physically open the chassis, and see that C30 was changed to a 1000pF cap.

 

[#2121313]

PICS:




Any info as to mods that may be done, or anything out of the ordinary and feedback is welcomed & appreciated!

Thanks.

 

[JD]

it hasn't got the 3 + mod but a red stripe is supposed to be closest to the c+ than any other stripes
the mod basically smoothes out the lead channel and makes the clean a bit more shimmery
if you are happy with yours I would leave or maybe get the r2 mod to balance r2 with the other channels

 

[holy-diver]

The red and blue sound almost identical to me.
What do you do to the blue stripe to red stripe, or "+" it?

 

[JOEY B.]

The blue stripe has nothing in the C30 circuit on the preamp board, the red stripe has a 500pF cap in the C30 position. The 1000pF in C30 will round off the highs in the lead channel a little more. I personally would leave the red stripe preamp as it is. The R2 volume mod and maybe a pentode/triode switch for the class-A power tube sockets will do just fine. 8)

 

[#2121313]

Thanks guys.

Yeah I have no intentions of changing anythings. Was just curious. If it aint broke don't fix it.

Yeah I really like the tone here.