MARK III + + mod

Mark I's, II's, III's and the almight IV

Moderators: Guitarzan, Grandor, ned, Platypus

paulyc
Mark I
Posts: 30
Joined: Tue Jan 24, 2017 1:28 pm

MARK III + + mod

Post by paulyc » Thu Nov 09, 2017 11:33 am

So I have a fully loaded MARK III blue stripe head with graphic EQ, reverb and Simul Class. I'd LOVE to get a combo cab for it as I have lots of great Mesa (and other) heads but no small portable rig. I would also love to have a + or a + + mod done by Mike B. I'm a hard rock and metal player (so think tones from 80s Sunset Strip hard rock to Metallica). Which mod (+ or ++) is the way to go ? Also, in a combo, what speaker would be a good choice (leaving the EVM out of it, too heavy !) ? I'm leaning toward C90 or a G12 H or K 100 ? What about the old Eminence 150 watt from the half back days ?

Thanks !

thediavlo
Mark II
Posts: 85
Joined: Tue Jun 20, 2017 4:46 pm

Re: MARK III + + mod

Post by thediavlo » Thu Nov 09, 2017 11:36 am

paulyc wrote:So I have a fully loaded MARK III blue stripe head with graphic EQ, reverb and Simul Class. I'd LOVE to get a combo cab for it as I have lots of great Mesa (and other) heads but no small portable rig. I would also love to have a + or a + + mod done by Mike B. I'm a hard rock and metal player (so think tones from 80s Sunset Strip hard rock to Metallica). Which mod (+ or ++) is the way to go ? Also, in a combo, what speaker would be a good choice (leaving the EVM out of it, too heavy !) ? I'm leaning toward C90 or a G12 H or K 100 ? What about the old Eminence 150 watt from the half back days ?

Thanks !
I didn't know there was a ++ mod. I would love one for my Blue stripe if there is one. I personally prefer the organic timbre speaker in my blue stripe, Great response and similar in sound to the EVM but with more Roll off on the upper treble frequencies. Bandit made a great comparison with it in his MKV.
Mark V, Mk III blue stripe combo Organic Timbre speaker, JP-2c, Triple Rectifier (reborn multiwatt)
Marshall 1960 full stack, 2 Mesa vertical 2x12, 1 Mesa thiele with EVM 12l black label.
LTD EC-1000x3
Schecter Hellraiser
1984 Gibson Explorer

paulyc
Mark I
Posts: 30
Joined: Tue Jan 24, 2017 1:28 pm

Re: MARK III + + mod

Post by paulyc » Thu Nov 09, 2017 11:42 am

Organic timbre ? IDK what speaker you're talking about, can you explain please ?

I've seen a clip on YT of someone playing psychodave's Mark III ++ and it sounds glorious. MB has confirmed the ++ mod exists...

thediavlo
Mark II
Posts: 85
Joined: Tue Jun 20, 2017 4:46 pm

Re: MARK III + + mod

Post by thediavlo » Thu Nov 09, 2017 12:36 pm

paulyc wrote:Organic timbre ? IDK what speaker you're talking about, can you explain please ?

I've seen a clip on YT of someone playing psychodave's Mark III ++ and it sounds glorious. MB has confirmed the ++ mod exists...
http://www.organictimbre.com/store/p1/R ... _G12F.html


Oh cool. So the Organic Timbre Rhapsody 12 is a speaker that has recently come to light on this board and I have heard great things about it, link is above.
Mark V, Mk III blue stripe combo Organic Timbre speaker, JP-2c, Triple Rectifier (reborn multiwatt)
Marshall 1960 full stack, 2 Mesa vertical 2x12, 1 Mesa thiele with EVM 12l black label.
LTD EC-1000x3
Schecter Hellraiser
1984 Gibson Explorer

thediavlo
Mark II
Posts: 85
Joined: Tue Jun 20, 2017 4:46 pm

Re: MARK III + + mod

Post by thediavlo » Thu Nov 09, 2017 12:40 pm

I just looked up the mod on youtube and it sounds pretty over the top and ridiculous. Definitely gonna look into sending mine off for that.
Mark V, Mk III blue stripe combo Organic Timbre speaker, JP-2c, Triple Rectifier (reborn multiwatt)
Marshall 1960 full stack, 2 Mesa vertical 2x12, 1 Mesa thiele with EVM 12l black label.
LTD EC-1000x3
Schecter Hellraiser
1984 Gibson Explorer

Stevie C
Mark I
Posts: 32
Joined: Thu May 20, 2010 12:47 pm
Location: Winston-Salem, NC

Re: MARK III + + mod

Post by Stevie C » Tue Nov 14, 2017 4:33 pm

paulyc, where are you located? I might be looking for a head shell for my mark iii.....if I decide to go that route, mine's loaded in a combo shell that's in great shape.

paulyc
Mark I
Posts: 30
Joined: Tue Jan 24, 2017 1:28 pm

Re: MARK III + + mod

Post by paulyc » Tue Nov 14, 2017 7:23 pm

New England.

jack s.
Mark II
Posts: 94
Joined: Wed Jun 07, 2017 9:37 am
Location: Brooklyn, NY

Re: MARK III + + mod

Post by jack s. » Mon Nov 20, 2017 10:27 pm

So this ++ mod has even more gain than a regular Mark III? I thought Mark IIIs already have a bunch more gain than the Mark IIC+ amps.

paulyc
Mark I
Posts: 30
Joined: Tue Jan 24, 2017 1:28 pm

Re: MARK III + + mod

Post by paulyc » Tue Nov 28, 2017 8:05 pm

The Mark III May have a bit more gain than a IIC+, but there is a + and a ++ mod for the Mark III that makes it awesome. The ++ mod is like 26 db more gain than stock.

jack s.
Mark II
Posts: 94
Joined: Wed Jun 07, 2017 9:37 am
Location: Brooklyn, NY

Re: MARK III + + mod

Post by jack s. » Tue Nov 28, 2017 10:27 pm

Oh nice:)

Stevie C
Mark I
Posts: 32
Joined: Thu May 20, 2010 12:47 pm
Location: Winston-Salem, NC

Re: MARK III + + mod

Post by Stevie C » Fri Jan 19, 2018 10:27 am

paulyc wrote:New England.
Still considering looking for a combo shell?

paulyc
Mark I
Posts: 30
Joined: Tue Jan 24, 2017 1:28 pm

Re: MARK III + + mod

Post by paulyc » Fri Jan 19, 2018 9:18 pm

Yes, PM sent

Stevie C
Mark I
Posts: 32
Joined: Thu May 20, 2010 12:47 pm
Location: Winston-Salem, NC

Re: MARK III + + mod

Post by Stevie C » Tue Jan 30, 2018 2:05 pm

paulyc wrote:Yes, PM sent
PM sent

jrb32
Mark III
Posts: 204
Joined: Wed Jan 31, 2018 8:32 am

Re: MARK III + + mod

Post by jrb32 » Fri Feb 02, 2018 10:33 am

I'm pretty sure the initial III+ mod essentially turns a MkIII into a Mk III Red Stripe with added IIC+ circuitry to make it close to the IIC+sound but not identical. The Red stripe was the closest of the Mk IIIs to the IIC+.

The ++ mod then adds a crazy amount of gain on top of that. My friend has a III++ modded by Mike B so it definitely does exist!

A blue stripe already has a stupid amount of gain. I've not compared it to a normal Blue Stripe but a stock coliseum Blue Stripe had way more gain than the III++

So if it's gain you're after, a + or ++ mod wouldn't add much but would change the overall sound of the amp.

Hope I am correct in this?

darkbluemurder
Mark II
Posts: 104
Joined: Fri Jul 28, 2006 5:58 pm
Location: Europe

Re: MARK III + + mod

Post by darkbluemurder » Mon Feb 05, 2018 8:09 am

Red stripe lead mode is indeed very close to Mk II C+ lead mode - only one capacitor (C30 - 500pf in the red stripe, 1000pf in the II C+) and one resistor (470k to ground before V2b in the red stripe vs. 680k in the II C+) is different. The cap difference has the bigger impact. The shunt resistor will affect the clean tone more than the lead tone because in lead mode it is in parallel with the 100k shunt resistor, thereby resulting in approx. 82k in the red stripe vs. approx. 85k in the II C+. This would not make any audible difference to the lead tone.

From comparing the schematics it is clear why the Blue stripe has more gain than the red. Red has the voltage divider of 220k to 100k (caps ignored for this purpose) whereas Blue has 470k to 470k. So in the red stipe 31% of the signal gets to the grid of V2b whereas it's 50% in the blue stripe. The tonal change you mentioned comes from the caps in parallel to the resistors - if the resistors are bigger the caps have a more noticeable effect.

In another thread where the III ++ was mentioned I posted some ideas on how to increase the gain in a Mk III. Still don't know what the ++ mod is.

Cheers Stephan

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