MkIII R2 Gain Boost mod. Am I alone on this?

[imbuyaboy]

Just out of curiosity, does anyone else here own a MkIII with the factory R2 "gain boost" mod? I notice that the R2 "volume" mod is often talked about here at the BB, but I never read any references to the gain boost mod.

For a little background, my MkIII is a blue-stripe, simul-class short head, with REV and EQ. I'm the second owner, and bought it back in 2000. The previous owner had Mesa do the gain boost mod to R2. Externally, it consists of a matching 3rd knob on the back of the head, located between and just below the Reverb and Presence knobs in a triangular layout. The mod can be activated by either flicking a factory mini toggle on the underside of the chassis, or by a footswitch plugged into the factory installed 1/4" jack on the back stamped "G.B." (gain boost). The knob adjusts the level of extra gain to R2, then it's activated by the toggle or the footswitch. Internally, I cannot say what's been done because (lazy me!) I've never gone poking around inside the chassis.

Anyway, I'm starting to think that maybe it's a rare factory mod that very few MkIII owners have ever had done, or, would even care to have done for that matter.

Boogie on!
Johnny

 

[trem]

IMO this is the kind of mod every Mark III owner should look for. How much gain does it add when you activate the gain boost? Thanks for the info.

~trem

 

[Ultron]

I have it on my III blue stripe....Mike B told me about it when I sent it in....he says it adds more "crunch".....it seems gainier to me....it was a cheap upgrade, and it does make the R2 more usable.....it's not Lead channel obviously, but it does have more gain.

EDIT
After rereading the original post, I'm not sure we're talking about the same thing.....I asked Mike to give more gain permanently to R2.....he changed some resistors..no knob on back, no switch, etc.

 

[psychodave]

I would love to have more gain on R2... on both my III and IV.

 

[boogietone]

I would love to have more gain on R2... on both my III and IV.

+1
I would like to have this mod done.

 

[imbuyaboy]

trem and Ultron,

It adds a considerable amount of gain to R2. The best thing is that it's user controlled. The desired amount of extra gain is first dialed in from the dedicated gain-boost pot on the back of the chassis, then activated manually by either the mini toggle (underside of chassis) for "full-time" extra boost while using R2, or by footswitch to the 1/4 jack on the back, also dedicated to the mod. Using the footswitch, you can be playing through R2 unboosted, then use the pedal to switch on the fly to a boosted R2...at whatever desired amount of extra gain the pot is set for.

Pretty cool Mike B. mod, and fairly rare it would seem. Would be interesting to know how many other MkIII owners have this, or if Mike B. still offers it. With the extra pot, 1/4" jack, mini toggle, and associated internals, it must be a somewhat extensive mod. By the way, I actually don't know who at Mesa did the mod. I was told by the previous owner it was Mike B., but I've never called him directly and didn't even ask when I was at the factory. Duh!

Gotta love the folks at Mesa!

 

[scottcrud]

How much more gain does the lead channel have over your R2 gain mod?

 

[trem]

Yeah, how much more gain? Can you do chugga-chugga-chugga (for the lack of a better word) (oh fine, aggressive percussive staccato palm muting) on the R2 with the boost on? Thanks.

~trem

PS: A clip would be very nice as well :wink:.

 

[scottcrud]

bump back to the top, we want answers!

 

[edward]

Yup, I am curious about this as well. I like my R2 as it is now, after I went to a NOS 12AT7 to calm *down* the mids and gain, and smooth-out the tone. So I use the R2 as a mild crunch alternative to the clean channel. So I am definitely curious as to what the R2 sounds like with *more* gain dialed in. Any clips here, or if there's a way to try it out temporarily that would be great!!

Edward

 

[imbuyaboy]

Amount of extra gain? Very sadly, I've been sitting here in Kyoto, Japan for the last three years "ampless!" All my gear is in storage in Los Angeles, so I'm currently unable to provide any clips of the mod in action, and honestly, am a little foggy about the exact amount of extra gain available. I seem to remember "palm muting" (chug-chug-Scorps style: for example, think the rhythm track to "Can't Live Without You" from their Blackout album) not being any problem at all.

Funny thing is that even I myself have spent only a limited amount of time checking out the mod. Most of the time I was noodling around on the lead channel of my MkIII. However, the R2 mod offers the user the ability to dial in the amount of extra gain, not a factory pre-determined amount. Or, no extra gain at all.

Probably best to call Mesa (Mike B.) directly and pick his brain about the exact details of the mod (amount of extra gain, what's changed internally, if the mod is still available, etc., etc. He worked on my amp back in 2003 before I flew to Japan, so maybe he remembers it. Feel free to reference my amp's serial number (16861), maybe he has it written down somewhere).

So, for redundancy.... nobody else here who has had this mod done?

Cheers, Johnny

 

[trem]

You may very well be one of the few (if any) who had this mod done to their amp. Funny though. This mod should have been VERY popular, for III and IV alike. Along with the separate bass/mid control mod idea for R1/R2 for IV that I proposed a month back, they would da bomb.

I wonder if boogiebabies can do this.

~trem

 

[BOOGIE-MAN63]

I will be finding out pretty soon how this mod sounds.Mike just finished this mod on my purple stripe.He used the pot on the direct out for the R2 master and put some resistors in line so the direct out would still function at a preset level without being adjustable.He did state there would be a small toggle under the chassis to switch it on or off.I hope it does the trick as I don't like using any kind of overdrive device.

 

[imbuyaboy]

I will be finding out pretty soon how this mod sounds.Mike just finished this mod on my purple stripe.He used the pot on the direct out for the R2 master and put some resistors in line so the direct out would still function at a preset level without being adjustable.He did state there would be a small toggle under the chassis to switch it on or off.I hope it does the trick as I don't like using any kind of overdrive device.

BOOGIE-MAN63, very interesting...and thanks for chiming in! That "small toggle under the chassis" points in the direction that Mike is giving your R2 the same mod he gave mine. For clarification, is Mike adding an additional "mini" pot on the back of the chassis to adjust the gain, as well as a 1/4" jack so that it is footswitchable?

Looking forward to hearing your assessment when it arrives!

 

[BOOGIE-MAN63]

He is just using the direct out pot.This way there will be no other holes in the chassis other than the mini toggle.The direct out will still work if needed.It will be preset to about 1.5--2 with resistors,about where I have used it before in recording.I am really looking forward to getting it.

 

[trem]

Great. Keep us updated. And again, post some pics and sound clips. Thanks!

~trem

 

[imbuyaboy]

Great. Keep us updated. And again, post some pics and sound clips. Thanks!

~trem

+1 BOOGIE-MAN63, very interested to see some pics when you get it. It will show me if the R2 gain-boost mod Mike is giving your MkIII is the same one he gave to mine.

johnny

 

[imbuyaboy]

He is just using the direct out pot.This way there will be no other holes in the chassis other than the mini toggle.The direct out will still work if needed.It will be preset to about 1.5--2 with resistors,about where I have used it before in recording.I am really looking forward to getting it.

Bumping this thread out of boredom, and also because the BBForum seems asleep half the time.

BOOGIE-MAN63, are you still awaiting your MKIII from Mesa? Interested to know your perspective on the R2 gain mod, and also see some photos if you get a chance.

Cheers, Johnny

 

[BOOGIE-MAN63]

I still haven't got it.Its in transit,but with Thanksgiving it is taking an extra day or so as they sent it ground.I will keep you updated on it.Sorry I didn't post on this for a while,as I forgot to check up on the post. KC

 

[Jarrod]

I still haven't got it.Its in transit,but with Thanksgiving it is taking an extra day or so as they sent it ground.I will keep you updated on it.Sorry I didn't post on this for a while,as I forgot to check up on the post. KC

When you get it, can you comfirm if the new gain pot works for the lead channel as well when your combining both R2 and Lead?

If so, I'm going to send her to Mesa. :twisted: