2c/c+ gain reduction mod.

[boogie-boy]

"It is also possible your amp was previously modded to reduce gain. It's a common mod on C+'s for blues players and what not....My amp has it and I'll eventually take it off."

This was mentioned in another thread, and I need to know more....

I have a January 1984 MKIIC with less gain than my other Boogies. It was previously owned by a Jazz-player. How can I spot if such a mod is done to it ?

I get a real tasty overdrive with Vol 1 and "lead drive" all the way up, but the other amps goes way over the top on these settings.

Stian

 

[Elpelotero]

go here for some references...this is my C+ that Boogiebabies diagnosed back in January.

http://forum.grailtone.com/viewtopic.php?t=9653

 

[Boogiebabies]

High quality pictures of the preamp, power board and the back of the pots please.

 

[Boogiebabies]

It makes no sense to me. You can alter between the Volume 1 and Lead Drive until you find your personal blues tone, including eq settings and presence. These are not one dimentional amps, but are stereotyped. You can alter the load on the tone stack, add bright reduction caps, increase plate load or plate supply resistors and fiddle with grid load resistors until the cows come home, but the amp can already provide a very fat clean or driven blues tone without modifications. The couple I have come across or heard about have neded up to be hacked tech jobs.

 

[Elpelotero]

I have no idea what that compression thing is...just disengage it for now until BB can you tell more about it.

It is also possible your amp was previously modded to reduce gain. It's a common mod on C+'s for blues players and what not....My amp has it and I'll eventually take it off.

Why is this a common mod for Blues Players? What's it's purpose?

-g

I think what I said came out wrong...It's not a common mod that all blues players know about and perform on the amp...Rather, it's a mod that somewhat lends itself to musical styles where less gain and brightness is used, i.e. Blues and Jazz. Boogies are well known for their clean sounds as much as their gain sounds, so many users of the old Mark amps are consequentially blues guys and what not.

I also may have stereotyped a bit because the previous owner of my C+ was a blues guy and he did the mod to the amp.

BB is right though, this amp really does not need any modding to produce a good SRV type blues tone...You just have to know how to dial the knobs.

 

[Boogiebabies]

What mod in particular? There's so many things to change, it would be nice to know what the one is.

 

[Elpelotero]

the bright reduction mod...

 

[JOEY B.]

Is this a photo of a stock C+ preamp board? It is an '85 head that I bought used and do not know if the preamp has ever been touched. I was trying to see if it had the brightness cap mod between V3 and V4. There seems to be some shadows in the photo. It would help to know exactly what I'm looking at :? . This amp has gain o'plenty. But so does my combo that has had a "make less bright-simul version" mod according to my Boogie invoice from about 18 months ago. Mike also spoke of some "gain reduction" mods, but I chose not to opt for them on my combo.

[/img]

 

[Boogiebabies]

It clear and stock. No mods.

I've seen the belly of that beast before. Clean, Clean, Clean brother.

 

[jvk]

Wow, no dust or gunk in there. Have you cleaned it Joey?

I've just taken apart a IIC and it's a proper mess inside. I've gone through a 200 pack of cotton ear buds and it still needs more cleaning, yuck. It looks like it lived next to a deep fryer for 20 years.

 

[Boogiebabies]

Heads generally remain Hermetically sealed and Sus mounts get 24 years of electrostatic dust blown all over them. I got a shot right after he opened it and it was like a new penny. Ding !!!!

 

[jvk]

Ahh, I see Dr. Boogie. Is there a strip of foam around the part of the chassis where the head touches it?

I've just bluprinted the RP10A. The circuit looks weird compared to the RP11A. The FX send and reverb both come right after V1B before the master controls. I've made a 1:1 copy of the pcb. I wish it was a RP11A

I'm going to build a Simul IIC+++ with EQ, reverb and with separated tonestacks. It'll also have separate channel masters. I'm putting on there the badest, fattest depth circuit there is. I've got equipment to make my own pcb with through plating using rivets, not flimsy chemically deposited copper. I have no doubt that it'll be not only better constructed than a Mesa IIC+, but it'll sound better. It's got 4 filter caps and a PT rated for 140w.

 

[Elpelotero]

can't wait to "hear" the results!

 

[Boogiebabies]

nO FoAm InVoLvED.

The chassis gets put right up to the cabinet. The screws pull it up and there is barely a gap in any. Even with the fan blowing, which is a joke on a head, the only dust you may see is in the empty hole between the footswitch jack and preamp out. On the Sus mounts the top of the chassis has a 1/4 inch gap and it attracts everything. I had a dead mosquito in one and full fledged dust bunnies. 3 days, 1 can of PCB clean and 40 Q-Tips later, Ding !!! Shiny again.

 

[JOEY B.]

Wow, no dust or gunk in there. Have you cleaned it Joey?

I've just taken apart a IIC and it's a proper mess inside. I've gone through a 200 pack of cotton ear buds and it still needs more cleaning, yuck. It looks like it lived next to a deep fryer for 20 years.

I did no cleaning on the inside of the amp, but the fan and underside of the chassis were funky like a monkey. I had a couple of minor issues when I first got this amp. Ed (Boogiebabies) was a lifesaver. About $1.50 worth of resistors made a world of difference.

 

[jvk]

nO FoAm InVoLvED.

The chassis gets put right up to the cabinet. The screws pull it up and there is barely a gap in any. Even with the fan blowing, which is a joke on a head, the only dust you may see is in the empty hole between the footswitch jack and preamp out. On the Sus mounts the top of the chassis has a 1/4 inch gap and it attracts everything. I had a dead mosquito in one and full fledged dust bunnies. 3 days, 1 can of PCB clean and 40 Q-Tips later, Ding !!! Shiny again.

So next time I look at Mark-xx gutshots I'll be able to identify if it's a head or combo just by looking out for skeetos and checking out how plump the dust bunnies are? sWeEt.

 

[jvk]

I did no cleaning on the inside of the amp, but the fan and underside of the chassis were funky like a monkey. I had a couple of minor issues when I first got this amp. Ed (Boogiebabies) was a lifesaver. About $1.50 worth of resistors made a world of difference.

Nice one Ed, you da man. The interweb is so **** useful, and the people inside it. I'm sure I could live without it (barely), but it's hard to imagine a web-less existence.