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

[trem]

Bump.

If it works for MIII, would it work for MIV? I sure hope it would!

~trem

 

[imbuyaboy]

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

Hey BOOGIE-MAN63, thanks for the reply. I also haven't checked this post for a while.

So, did you get your MKIII back from Mesa in one piece?
Very interested to learn your impression of the mod, and see some pix as well in order to compare them to the mod Mike B. did on mine. Sorry that I can't take (and post) any pix of that mod on my head, it's currently in storage in Los Angeles and I'm currently in "MkIII withdrawal" here in Japan.

Post an update when you can.

Cheers, Johnny

 

[edward]

...
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? .... :twisted:

"Combining" R2 and Lead?? What do you mean by that?

Edward

 

[trem]

...
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? .... :twisted:

"Combining" R2 and Lead?? What do you mean by that?

Edward

I think he was pertaining to the fact that when you channel switch from R2 to lead, some of the R2 sound is still there, and whether the gain mod also change this, hence adding even more gain.

~trem

 

[edward]

Hi Trem,

This is a revelation to me. I "thought" that when one switches to/from Lead channel, that is exactly what is happening: switching in/out of the Lead channel. Whether it is R1 or R2 that is engaged is irrelevant. Am I wrong on this? Are you saying that if I am in R2 when I switch to Lead, it will sound different as opposed to being in R1 then switching to the Lead? Thanks!

Edward

 

[Boogiebabies]

"Combining" R2 and Lead?? What do you mean by that?

Edward

I think he was pertaining to the fact that when you channel switch from R2 to lead, some of the R2 sound is still there, and whether the gain mod also change this, hence adding even more gain.

~trem

Absolutely correct. The R2 is still in series with the lead channel unless it is switched off.

 

[trem]

Hi Trem,

This is a revelation to me. I "thought" that when one switches to/from Lead channel, that is exactly what is happening: switching in/out of the Lead channel. Whether it is R1 or R2 that is engaged is irrelevant. Am I wrong on this? Are you saying that if I am in R2 when I switch to Lead, it will sound different as opposed to being in R1 then switching to the Lead? Thanks!

Edward

Hey Edward. Yeah, you're right, it's gonna be different. Something to do with the switching circuit not disengaging part of the R2 circuitry when switching to lead.

~trem

 

[trem]

Absolutely correct. The R2 is still in series with the lead channel unless it is switched off.

Hey Boogiebabies,

I would love to hear your insight about this mod, and whether this would be applicable to Mark IV as well. Thanks.

~trem

 

[phyrexia]

Hi Trem,

This is a revelation to me. I "thought" that when one switches to/from Lead channel, that is exactly what is happening: switching in/out of the Lead channel. Whether it is R1 or R2 that is engaged is irrelevant. Am I wrong on this? Are you saying that if I am in R2 when I switch to Lead, it will sound different as opposed to being in R1 then switching to the Lead? Thanks!

Edward

Use two footswitches, and then when you're in the lead channel, switch back and forth between R1 and R2 with the other switch. You should be able to tell a difference.

 

[edward]

Wow, this IS a revelation to me. Sorry it's a bit OT to the orig thread, but thanks for this important bit of info ...never knew that before. I will listen to the diffs myself with separate footswitches. Thanks a bunch guys!!

Edward

 

[Restless Rocks]

I've always thought of it as Lead1 and Lead2. Almost like having 4 channels to me! But you must have both foot switches (R1/R2 and Lead/Rythm) to utilize it. Come to think of it: this could explain why some guys think the MkIII lead ch to be fizzy sounding coz that's exactly the effect I get when engaging Lead while R2 is on, especially when you're running the input gain really high (8 or above). Perhaps a problem solved by accident!!!!!

 

[imbuyaboy]

I think he was pertaining to the fact that when you channel switch from R2 to lead, some of the R2 sound is still there, and whether the gain mod also change this, hence adding even more gain.

~trem

Absolutely correct. The R2 is still in series with the lead channel unless it is switched off.

Wow. Great info! Thanks trem, edward, and Boogiebabies! Haha, this is probably more interesting than my original post. Goes to show how LITTLE time I spend footswitching between channels.

BOOGIE-MAN63, still anxious to hear your opinions about the mod. Hope it's working out well for you.

 

[edward]

OK, apologies in advance for the quasi-hijack of this most worthy thread. But THANKS!

I just plugged into my MKIII and sure enough, R2 most certainly colors the Lead channel if left on. And I don't really care for it. Just as Restless said it, the Lead turns kinda fizzy with R2 left "in," and the upper voice loses indiv note definition. Although not bad for chords (played fast and loud ) as R2 does seem to add a bit of grit on top of what already has been dialed in. Still, I think I'll leave my Lead channel "pure."

Funny how in the time that I've owned and played it, I never hit that combination ...guess I always went straight to Lead from my R1 and never from R2, and I use R2 really as a mild crunch alternative to an otherwise pretty clean R1. Again, great info Trem, phyrexia, and BoogBab ...thanks a bunch!

Edward

 

[Boogiebabies]

Absolutely correct. The R2 is still in series with the lead channel unless it is switched off.

Hey Boogiebabies,

I would love to hear your insight about this mod, and whether this would be applicable to Mark IV as well. Thanks.

~trem

You can do the R2 mod for keeping the channels even, as it is needed.
For gain mods, just pick your poison. From looking at the schematic, I would probably swap the V2A grid load resistor with a pot to adjust the R2 gain. The other mods I would look at are cathode bypass caps. You can wire them with a switch from Radio Shack and depending on what value cap, 5, 10, 15 or even .22uf caps will give you varying amounts of gain boost.

 

[trem]

Absolutely correct. The R2 is still in series with the lead channel unless it is switched off.

Hey Boogiebabies,

I would love to hear your insight about this mod, and whether this would be applicable to Mark IV as well. Thanks.

~trem

You can do the R2 mod for keeping the channels even, as it is needed.
For gain mods, just pick your poison. From looking at the schematic, I would probably swap the V2A grid load resistor with a pot to adjust the R2 gain. The other mods I would look at are cathode bypass caps. You can wire them with a switch from Radio Shack and depending on what value cap, 5, 10, 15 or even .22uf caps will give you varying amounts of gain boost.

And this is applicable also to Mark IV right? Please say yes :lol:. I sure can't put into perspective what you're saying until I have my Mark IV opened up. Thanks!

~trem

 

[Boogiebabies]

Hey Boogiebabies,

I would love to hear your insight about this mod, and whether this would be applicable to Mark IV as well. Thanks.

~trem

You can do the R2 mod for keeping the channels even, as it is needed.
For gain mods, just pick your poison. From looking at the schematic, I would probably swap the V2A grid load resistor with a pot to adjust the R2 gain. The other mods I would look at are cathode bypass caps. You can wire them with a switch from Radio Shack and depending on what value cap, 5, 10, 15 or even .22uf caps will give you varying amounts of gain boost.

And this is applicable also to Mark IV right? Please say yes :lol:. I sure can't put into perspective what you're saying until I have my Mark IV opened up. Thanks!

~trem

The MK IV does not suffer from the same effects of the channels being in series. The gain boost is already built in to the MK IV in the form of the Mid Gain switch. JVK has a gain boost for the MK IV, so you might want to PM him. I have yet to really get into the electronics layout of the MK IV. I will be sitting down with the MK III over the holidays.

 

[GIG4FUN]

ttt !!

I have my Mark III on its way to MB. I am pretty confident I want the R2 Volume mod BUT it seems as I may NOT want this one. Anyone have theirs done since the OP and others had discussed this some time ago...

Any new information or comments would be helpful for my decision making.

thank you.

 

[Fastforded]

BUMP any new info, or PICS???

 

[Fastforded]

Absolutely correct. The R2 is still in series with the lead channel unless it is switched off.

Hey Boogiebabies,

I would love to hear your insight about this mod, and whether this would be applicable to Mark IV as well. Thanks.

~trem

You can do the R2 mod for keeping the channels even, as it is needed.
For gain mods, just pick your poison. From looking at the schematic, I would probably swap the V2A grid load resistor with a pot to adjust the R2 gain. The other mods I would look at are cathode bypass caps. You can wire them with a switch from Radio Shack and depending on what value cap, 5, 10, 15 or even .22uf caps will give you varying amounts of gain boost.

What schematic? Wondered if this was a possible DIY mod? Be interesting to see the schematic of one stock and one with the gain mod...

And what the difference in the switch and pot? Other than, as a guess, the pot allows radial adjustment where e switch might be a/b or even a/b/c?