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 Post subject: Mark III Speakers?
PostPosted: Sat Mar 25, 2017 11:00 am 
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Mark I

Joined: Sun Mar 21, 2010 2:32 pm
Posts: 32
Long time Mark fan. Just curious what your favorite speakers are besides the mighty EV12L and MC90?

I remember liking the Scumback H75's, but is has been a long time since I have heard that amp with those.

What about Celestion G12T-75's? Others?


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 Post subject: Re: Mark III Speakers?
PostPosted: Sun Mar 26, 2017 12:25 am 
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Mark III

Joined: Sun Mar 06, 2016 10:38 am
Posts: 228
Location: Western Colorado
With my Mark III blue stripe:

- EVM12L I don't care for the sound. (and I do like it with my Mark II)
- Vintage 30 sounds good, but a little middy / harsh because the amp is so bright.
- G12T-75 I actually like best with my III because it's a darker speaker, and the amp is bright. Of all my Marks I like this speaker best with the III.
- G12H-75 Creamback sounds great, but more vintage flavor. Similar to the V30 but less middy.


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 Post subject: Re: Mark III Speakers?
PostPosted: Wed May 03, 2017 5:42 pm 
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Mark III

Joined: Fri Jan 28, 2005 5:32 pm
Posts: 174
In addition to Black Shadow C90s, I've had excellent results with Celestion Lead 80s and GH100s, although to really shine, they should be paired with the mighty EVM12L as the anchor. :D

_________________
Quad Preamp/2:90
MkIII+ Simul-Class & MkIVb
Mark 4x12 Stack
Charvel 650 Custom/EMG85/SLV/SLV+SPC
Charvel San Dimas I Koa USA
Jackson Soloist Pro MIJ
B.C. Rich Eagle Evo2/Air Norton
ESP Eclipse EMG 81/60
Ibanez UV7BK
Charvel 475 Exotic
Fender Tele USA


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 Post subject: Re: Mark III Speakers?
PostPosted: Mon May 22, 2017 3:35 pm 
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Donating Member

Joined: Wed Oct 22, 2014 3:50 am
Posts: 14
Location: London
Any love for eminence? Swamp thang? Im putting a new cab together.


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 Post subject: Re: Mark III Speakers?
PostPosted: Sun Aug 06, 2017 8:07 pm 
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Mark II

Joined: Wed Dec 23, 2015 9:50 am
Posts: 108
I have a Warehouse ET-90 in my Mark iii Red stripe Imbuia cab and MY God it is absolute Heaven!

_________________
JP-2C
1985 Mark iii Simul Class Black Dot w/Red Stripe upgrade
1987 Mark iii Coliseum Purple Stripe
1987 Red Stripe Combo
Mark IVb
Rocket 4Forty
JP2C (#2)


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 Post subject: Re: Mark III Speakers?
PostPosted: Fri Jan 26, 2018 12:41 am 
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Mark I

Joined: Sun Mar 21, 2010 2:32 pm
Posts: 32
Necro thread!!!!

I am picking up a MKIII Blue stripe this weekend. I have a 2x12 loaded with G12T-75's waiting. Will report later.

Good to be back in the family.... :mrgreen:


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 Post subject: Re: Mark III Speakers?
PostPosted: Fri Jan 26, 2018 5:13 am 
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Mark II

Joined: Fri Jul 28, 2006 5:58 pm
Posts: 104
Location: Europe
I have had the following speakers in my Purple Stripe:

- Black Shadow EVM 12 L: very midrange focussed in the combo cab, little bass but very loud. Sounds much better in a separate cab
- Black Shadow C-90: thin, harsh and gritty
- Eminence MOD 12: this is my current speaker and my favorite so far. Sounds smoother and fuller than both of the others.

Still, the best tone IMHO is to be had through a separate cab. I feel that the small hardwood combo cab chokes a lot of bass and fullness out of the speakers.

Cheers Stephan


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 Post subject: Re: Mark III Speakers?
PostPosted: Sat Jan 27, 2018 6:16 pm 
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Mark I

Joined: Sun Mar 21, 2010 2:32 pm
Posts: 32
Got the Mkiii blue stripe. I went ahead and performed the + mod on the clean and lead channel. Much better for my needs. Running through a 2x12 loaded with g12t-75's and it sounds righteous!


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 Post subject: Re: Mark III Speakers?
PostPosted: Wed Jan 31, 2018 7:58 pm 
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Mark I

Joined: Tue Jan 24, 2017 1:28 pm
Posts: 30
You can do your own + mod ??? Wanna do mine ? Or share the changes via PM ? I’d LOVE to have my Mark III Blue stripe given a + or, even better, a ++


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 Post subject: Re: Mark III Speakers?
PostPosted: Thu Feb 01, 2018 4:22 am 
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Mark II

Joined: Fri Jul 28, 2006 5:58 pm
Posts: 104
Location: Europe
Not sure about the ++ mod - never read any details of that. What I know about the + mod is (and please correct me if I am wrong):

1. Change C30 from 500pf to 1000pf or add a 1000pf in amps that don't have it (e.g. Blue and Green stripes). That is like Mark II C+ and would smooth out the lead mode. Simulclass amps do not have this cap so if your amp is simulclass you may want to skip this step.
2. Change the cap in parallel to the 3M3 resistor from 10pf to 20pf. This should mainly affect the clean mode. Signal flows through it also in lead mode but it is likely swamped by the lead mode.
3. Change C516 in the presence circuit from 0.01uf to 0.005 (or 0.0047)uf. That is also like Mark II C+ and makes the amp less dark at low presence settings and makes the presence control work more gradually over its range.

I would definitely recommend no. 3, have not tried no. 2 and think that no. 1 is entirely personal preference.

Would love to hear details about the ++ mod.

Cheers Stephan


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 Post subject: Re: Mark III Speakers?
PostPosted: Thu Feb 01, 2018 6:17 am 
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Mark I

Joined: Tue Jan 24, 2017 1:28 pm
Posts: 30
I was told the ++ adds 20 db or so gain, which I think would be very hard to do without adding a tube stage, anyone have any ideas ?


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 Post subject: Re: Mark III Speakers?
PostPosted: Fri Feb 02, 2018 7:35 am 
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Mark II

Joined: Fri Jul 28, 2006 5:58 pm
Posts: 104
Location: Europe
Indeed there are not many places in the Mk IIC+/III/IV overdrive circuits where you can increase the gain without running the risk of grossly overdriving one of the following stages (by "grossly" I mean that one stage is so overloaded that it goes into blocking distortion). By looking at the schematics I have the following ideas:

You could alter the 270k/68k voltage divider after V3a (first gain stage of the lead drive circuit) and increase the gain by upping the 68k to 82k or 100k and at the same time reducing the 1000pf cap in parallel to the 68k to 500pf. Alternatively you could just drop the 270k to 220k. Both will increase the gain slightly. On paper I would prefer decreasing the series resistor instead of increasing the shunt resistor as that would also reduce the bass a tiny bit which is preferable for higher gain. Increasing the shunt resistor would also increase the bass which is generally not desirable in high gain. I would not do both mods at the same time as it could be too much. When doing these mods I would also consider reducing the 0.022uf coupling cap off V3a with a 0.01uf to reduce bass.

You could also increase the 270k plate resistor on V3b to 330k for more asymmetrical clipping.

You could adjust the 0.22uf lead bright cap to 0.47uf for a bit more gain. This will of course only be effective when the lead bright switch is engaged. The lead bright switch then becomes a lead boost switch (more overdrive, not more volume). This is the only mod of this list I actually tried in an amp and the one I would recommend as it leaves the signal shaping between the stages intact (assuming you like the basic character of the amp).

Finally you could adjust the voltage divider section coming off of V3b (220k II 250pf series to 100k II 500pf to ground in the IIC+ and Red Stripe, 470k II 120p series 470k II 680pf on the Blue and Green Stripes) by making the shunt resistors slightly larger to drive V2b harder (yes, V2b does contribute overdrive in the lead mode, even though it does not in the clean mode unless you crank the volume).

Frankly I don't see the need to do any of these mods in my Mark III as it has more than enough gain in stock form to play any kind of metal, unless your main axe is equipped with something like lipstick pickups which have about half the output of a low output single coil.

And by comparing the various Mark series schematics it is interesting to see which values were never changed from one model to another. They changed the resistor in parallel to the lead drive pot (330k or 470k, which basically affects the bass content when turned up full only), the cap in parallel to the 270k plate resistor (none, 500pf or 1000pf), the cap in parallel to the 68k to ground (500pf or 1000pf) and the voltage divider combination after V3b but they never changed any of the following:

- the 120pf in parallel to the shunt resistor on the lead drive pot
- the 0.022uf coupling cap after V3a
- the 270k/68k voltage divider and
- the 270k plate resistor of V3b

I guess there is a reason for that (which may be as simple as that they liked these values better than anything else they tried).

Still no idea what the ++ mod is.

Cheers Stephan


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 Post subject: Re: Mark III Speakers?
PostPosted: Sun Feb 04, 2018 9:53 am 
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Mark I

Joined: Thu May 20, 2010 12:47 pm
Posts: 32
Location: Winston-Salem, NC
Speaking of speakers, I just saw this new celestion, just introduced at NAMM. Only weighs 5.5lbs:
https://celestion.com/product/199/neo_250_copperback/

Could be interesting.


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 Post subject: Re: Mark III Speakers?
PostPosted: Mon Feb 05, 2018 9:07 am 
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Donating Member

Joined: Thu Oct 28, 2010 3:33 pm
Posts: 24
Location: CA. USA
The Celestion neo 250 does look promising, and then there is this new offering from our friends at Eminence. http://www.eminence.com/speakers/speake ... gend_EM12N

Looking forward to seeing and hearing demos of both of them.

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mk IVb,
mk IIb


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