The Mark IV thread....!!

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

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guitarrero
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Re: The Mark IV thread....!!

Post by guitarrero » Sat May 28, 2011 4:31 am

I started a thread yesterday because i have some trouble with my Mark IV. Maybe some of you just check this thread and know some help, it's quite urgent:

I'm using a Mark IV (b) and a tc electronic g-system (4-cable-method) for quite a while now and everything worked nicely. Well, until last week... all of a sudden my tone became very flat, silent and dead. The gain was almost completely gone in the "Rhy 2"- and "Lead"-Channel. Well, i tried to locate the problem and unplugged my g-system, played through the amp only and it works and sounds perfect. Switching channels with the G is still possible when i hook up the relais-cables and stuff. But as soon as the guitar signal goes in the G-System first and takes the whole ride through the FX-Loop and the circuit of the g-system the problem remains.
My first guess is that there must be something wrong with the FX Loop, but i'm not sure... does this sound familiar to anyone of you? Anyone with some good advice? Thanks a lot in advance! Please, save me! :)

(The separate topic can be found here: http://forum.grailtone.com/viewtopic.php?f=27&t=53974)
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greatmutah
Mark I
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Re: The Mark IV thread....!!

Post by greatmutah » Tue Sep 13, 2011 1:21 am

Figured I'd contribute a little info to this. I bought my Mark IV about 4 months ago and couldn't be happier. It's a IVa with SN 1470. It's an old bird for sure. It was actually originally a rackmount unit but I replaced the rack with a proper headshell from a later Mark IV (It's taurus instead of bronco). I still have the rack as I'd like to keep the original components it came with as that's how it was sold in the first place. I'm one of the few that loves this thing with V30s. I run it through my Recto 2x12 and I absolutely love this thing. I eventually would like to try this thing through a theile cab with a EV12L in there but on the whole, this thing is my tone. It does everything my Recto's couldn't do. I love the clean. I use the crunch channel sparingly as it's cool, but I just haven't gelled with it yet. I live in the lead channel though and that I couldn't be happier with. It just rips. Leads are effortless to play and chords and single notes alike cut like it's no one's business. This thing sounds huge in its own way. It's a focused sucker punch with a nice crisp chime on type that never feels buzzy or harsh. I'd like to get a hold of a IVb and a/b the two back to back just to see the differences. I realize they're probably not much, but it'd just be fun to do. Overall this amp is amazing. I have to give thanks to the Board and this thread because it helped me research these things and made my jump into them much easier than it would've been solo.
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Mesa/Boogie Stiletto Trident Stage I
Mesa/Boogie Mark V
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Mesa/Boogie Recto 2x12
Assorted Les Pauls, Strats and V's.

buzzlane
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Re: The Mark IV thread....!!

Post by buzzlane » Thu Sep 22, 2011 2:27 pm

Hi all,

Newb here. Just picked up a 2003 MKIV shorthead in showroom condition! :D Never left the guys house, hardly broke in. He said it was too complicated to set up and so it just sat there! Paid $800 with the 3/4 back 1x12 cab. Have the cab sold already, as I will be using an Avatar 2X12.
Will I be ok to use the 2 4ohm spkr jacks to run 2 16ohm spkrs? I assume it's ok to go higher. The manual states it's ok to run 2 8ohm spkrs from the 4 ohm jacks. Have 2 Avatars, one with Greenbacks and one with G70 Celestions. Anyone have a preference between those models? Haven't had a chance to really play with my new toy yet.

hagcel
Mark I
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Re: The Mark IV thread....!!

Post by hagcel » Tue Feb 21, 2012 11:22 am

New Mark IV owner here.

When I turn up the drive on the lead channel it gets real buzzy, almost staticy...not a pleasant overdrive sound. I'm going to move some tubes around and see if that helps.

It also has JJ 6L6s installed so I'm going to switch those out to Mesa tubes which should help...

The cleans sound great but even a little gain on channel 2 - sounds good for single note leads but with chords sounds buzzy...

How can I diagnose a filter cap problem?

I'm going to start with tubes

Retu
Donating Member
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Re: The Mark IV thread....!!

Post by Retu » Fri Feb 24, 2012 7:55 am

hagcel wrote:New Mark IV owner here.

When I turn up the drive on the lead channel it gets real buzzy, almost staticy...not a pleasant overdrive sound. I'm going to move some tubes around and see if that helps.

It also has JJ 6L6s installed so I'm going to switch those out to Mesa tubes which should help...

The cleans sound great but even a little gain on channel 2 - sounds good for single note leads but with chords sounds buzzy...

How can I diagnose a filter cap problem?

I'm going to start with tubes
Hi,

When you have an overdriven / distorted sound, be sure that the amps reverb is set to zero.

JEmerson
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Re: The Mark IV thread....!!

Post by JEmerson » Thu Mar 08, 2012 1:56 pm

Does anyone have blueprints for me to make a short head from?

Being in the UK I think it'll be the most cost effective way to build my own.

I assume because everything (with the exception of the reverb and fan) are chassis mounted(?!) I simply create a box with all the necessary mounting points and simply slot the chassis into the head?

Then I'm not going to intending on installing the reverb but leave it and the speaker in the old chassis. I assume the fan is necessary can someone illustrate where it should be placed in the head?

Also how is the bottom of the head cutaway if I wanted to install the reverb?

Finally what materials are suitable for creating the head cabinet. I will be using Tolex to cover the head.

Cheers,
Josh

rummy
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Re: The Mark IV thread....!!

Post by rummy » Wed Apr 04, 2012 5:03 pm

New Mark IV combo owner here. I’ve had mine for about two months, and I’m digging it more each day. Is there a place where I can look up serial numbers? I got mine from Craigslist, and it is wrapped in green vinyl and has a tan grille. It looks better than a new brand new amp, and I’m really curious to see what year this was made in.
Also for the past two months, I’ve swapped the outer tubes between 6L6s and El34s probably 10 different times. I think I’m coming to a conclusion that I prefer all 6L6s rather than mixed. It’s pretty crazy to think that the original Mark IV is over 20 years old, and how they have so many brilliant features built into it.

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Last edited by rummy on Mon Apr 30, 2012 8:34 am, edited 1 time in total.

wolf
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Re: The Mark IV thread....!!

Post by wolf » Tue Apr 17, 2012 10:27 am

Hi everybody...I have chance to trade my curent amplifier for Mesa Mark IV which I wish to own one long time...I´m going to see amp next week so I´m seriously looking forward...The guy sent me just few picture and one think what I´m not sure is transformer look...I´ve seen many pictures of back side of Mark IV (many as you can find on internet) but no one transformer looks like this one...Can you someone verify it if it´s original just from this photo?Thanx a lot...

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Mesa Dual Rectifier 2 ch /F revision/
Mesa Dual Rectifier 3 ch
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sduck
Mark II
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Re: The Mark IV thread....!!

Post by sduck » Tue Apr 17, 2012 10:09 pm

No, that's probably some kind of replacement transformer. At least mine doesn't look like that. Also the mode switch has been changed, which is only a cosmetic issue, but it makes one wonder "why?".

Oh - I see you have an international version - perhaps that explains the various differences I see between yours and mine?

wolf
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Re: The Mark IV thread....!!

Post by wolf » Tue Apr 17, 2012 10:56 pm

Yeah it´s european version man...
Mesa Dual Rectifier 2 ch /F revision/
Mesa Dual Rectifier 3 ch
ESP guitars...

ostepop
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Re: The Mark IV thread....!!

Post by ostepop » Thu Jul 26, 2012 8:32 am

Hi all! :D

New guy here. Just have a quick question regarding the reverb in my newly acquired Mark IV rev. A.

I'm not getting any reverb out of it, but the previous owner did install a 12ax7 tube instead of a 12at7 tube in the reverb circuit. I haven't tried switching to the correct tube, but I don't really care about the reverb.

So are there any possible downsides or issues when using the amp without the reverb tube installed?

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thunda1216
Mark IV
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Re: The Mark IV thread....!!

Post by thunda1216 » Fri Jul 27, 2012 1:49 pm

I have found a Mark IV combo at a pawn shop for $579. In average used condition, with an Altec speaker that resembles the EV12L. No footswitch. Is this a reasonable price?

thanks.
When Gibsons are outlawed, only outlaws will have Gibsons

sduck
Mark II
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Re: The Mark IV thread....!!

Post by sduck » Fri Jul 27, 2012 11:06 pm

It's a great price! You can get a new footswitch from mesa. The combos sell for twice that on ebay.

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thunda1216
Mark IV
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Re: The Mark IV thread....!!

Post by thunda1216 » Sat Jul 28, 2012 2:40 pm

thank you so much!
When Gibsons are outlawed, only outlaws will have Gibsons

bgh
Mark III
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Re: The Mark IV thread....!!

Post by bgh » Sun Jul 29, 2012 8:07 am

ostepop,

According to the Mark IV manual, there are 2 tubes involved in the reverb process: V4B is the reverb send and V3B is the reverb return.

The other half of V4 (V4A) is the 'second lead high gain stage'.
The other half of V3 (V3A) is the 'first lead high gain stage'.

If either is missing, the lead channel would be rather shot. I do not know if the other channels would work or not. (I don't know if Mesa has a fail-safe built in for situations where a pre-amp tube is missing).

For me, I would not try it.

The manual is actually very good and should be read multiple times. It contains gobs of information and hints.
You can download the manual here:
http://www.mesaboogie.com/manuals/Mark%204.pdf
Lefty guitars: Gibson SG standard (1977) • Gibson LP custom (1979)
Amps and such: Mesa Boogie Mark IV-B • Mesa Nomad 45 • Mesa TA-30 • Effectrode Blackbird • Kingsley Jester • AMT SS-11a • Zoom G5

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