The Mark IV thread....!!

[Monsta-Tone]

He has a Revision A. His Reverb circuit is quite a bit different from the Revision B.
On the A, V4 is a 12AT7. This is a lower gain, but higher current tube. I have seen several vintage Fender amps that have blown Reverb transformers because someone used a 12AX7 tube instead of a 12AT7.

I would say that it is worth it to install a new or good AT7 and see if the Reverb comes back. I have a copy of the Mark IVA manual if anyone needs it too. Can't remember who sent it to me, but I would be happy to email it to anyone that needs it.

 

[HBob]

He has a Revision A. His Reverb circuit is quite a bit different from the Revision B.
On the A, V4 is a 12AT7. This is a lower gain, but higher current tube. I have seen several vintage Fender amps that have blown Reverb transformers because someone used a 12AX7 tube instead of a 12AT7.

I would say that it is worth it to install a new or good AT7 and see if the Reverb comes back. I have a copy of the Mark IVA manual if anyone needs it too. Can't remember who sent it to me, but I would be happy to email it to anyone that needs it.

I have the old one done on a typewriter and Mesa Boogie stationery! Is that the one you have?

 

[Monsta-Tone]

That's the one. I think someone here scanned it and emailed it to me years ago.

 

[HBob]

I got my amp in '92 and thought at the time it was very "mom and pop". Very cool.

 

[cradlefish]

He has a Revision A. His Reverb circuit is quite a bit different from the Revision B.
On the A, V4 is a 12AT7. This is a lower gain, but higher current tube. I have seen several vintage Fender amps that have blown Reverb transformers because someone used a 12AX7 tube instead of a 12AT7.

I would say that it is worth it to install a new or good AT7 and see if the Reverb comes back. I have a copy of the Mark IVA manual if anyone needs it too. Can't remember who sent it to me, but I would be happy to email it to anyone that needs it.

I don't believe using a 12ax7 is going to hurt the amp in any way. I don't know the reason for using the 12at7 over the 12ax7. I have never had a problem with any of my amps that I've owned using a 12ax7, but i'm sure there's a reason why mesa chose to use that type of tube for the reverb.

 

[Monsta-Tone]

The AT7 is higher current, less gain.
The AX7 may result in not enough reverb.
I've repaired a lot of vintage Fender amps where someone put an AX7 in the reverb driver slot. It blows the reverb transformer most of the time......

 

[cradlefish]

The AT7 is higher current, less gain.
The AX7 may result in not enough reverb.
I've repaired a lot of vintage Fender amps where someone put an AX7 in the reverb driver slot. It blows the reverb transformer most of the time......

thanks for shedding some light on the differences. I'll test out a at7 and check out difference.

 

[Markedman]

I just don't get how ppl can honestly say their MKIV can't get super tight, saturated, or lacks low end

+1

If I had a Mark IV with any of those symptoms I'd do the following:

1) Preamp tube swamp and if that didn't work,
2) Poweramp tube swap and if that didn't work,
3) package it up and send it to Petaluma for a checkup.

That about sums it up, but I'll add that your guitar and pick-up choice will make a huge difference. Today our bass player couldn't make it to practice and I noticed the low end of the amp was super tight when I used the bridge pick-up compared to the neck pick-up. I never really noticed that there was that much more tightness because the bass guitar picked up the slack. I did make some changes in EQ and gain structure as the practice went on and now I wonder how it will sound when we get together this week and if I'll resort back to the earlier settings.

 

[mazzith]

Today my other guitarist found a Mark IV A compact head on craiglist (without pedal) for $800.
I have the Mk IV B head and we played both heads through the same cabinet using the same guitar with exact same settings. The tone differences was very minimum.
Later on we are going to do some side by side recording comparisons.

 

[darkalone]

Hi everyone. Got an issue with my Mark IV and I was hoping someone could steer me in the right direction. I created a thread outside of this one. Basically, my volume dropped considerably across the board, gain channel also sounds like it's crapping out, and now the signal seems sort of intermittent.

Thread: http://forum.grailtone.com/viewtopic.php?f=3&t=65570

I'm guessing it's in need of a re-tube. But that leads to all sorts of other questions, mainly, what kind. :?

Anyway, any help is appreciated. Thanks guys.

 

[Markedman]

I put new tubes in my Mark IV on Saturday. Someone gave me a pair of Mesa STR 420's so I tried them in the outer sockets at first along with the GT 6L6's in the middle. That sounded awesome, nice and tight. Next I tried the =C= el34's in the outer sockets and that had the typical "jangly" sound associated with Marshall amps. Next I put the 420's in the middle, 34's in the outer sockets and have been playing it that way trying different settings. I'm using the amp in simul-class, triode, full power, and I think that is what I'll use. My band is on holiday break, and I love my other Mark amps when I play with the band, so I never really use the Mark IV live unless it is at an "open mic," home practice or playing at a friend's house. I'd say the combination of 6L6 & el34's is best all around, but a quad of 6L6's would be my choice for metal only, the amp sounds less spongey and much tighter with 6L6's. I have different pre-amp tubes on the way.

 

[boogietone]

I sent you a Mark IV manual or something like that last year, I think.

That's the one. I think someone here scanned it and emailed it to me years ago.

 

[andrewraharjo]

Hi everyone, I just got my used wide body mesa boogie mark IVB 2 days ago. It's a beautiful combo and I'm thinking of make as head cab which I'm looking for head shell now.

I tried to call Mesa the other day and they quoted me with $356. Does anybody here have any idea for cheaper solution ? I heard there is member here "gts" who can make it happen for less than Mesa quoted me. Does he still make head shell these days ?

 

[philip]

hey there,
new to the forum and I just picked up a Mark IV last week.
amazing amp! so far I was able to play it only at bedroom levels,
but even pretty quiet it does sound incredible.

apparently it's a pretty early on, too.

does anyone know what the jack in the last image is for?

 

[tonejam]

No, but congratulations on the amp!

 

[r_cod_81]

Just got me a MkIV off ebay in Newcastle - S/N 12942. Guy had re-housed the head in an oak box and it's very nice, he had to take the reverb out to do it though. Still got the original Boogie head shell with the reverb tank. Got the FU-3 switch with it too, of a lovely retired chap who now uses something lighter. He only ever used the clean channel so it'll be good to get the lead channel working.

A common complaint I've had is that my guitar can't be heard live - this should fix that, this ****** is LOUD!

http://www.ebay.co.uk/itm/171549281524?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

[andrewraharjo]

Hi folks just quick question about Mark IV

I'm on my way for changing the power tubes with 6l6 STR mesa. My question is do I really need to change the preamp tubes as well or can I just leave them ? I remember I changed the preamp tubes recently but can't recall the power tubes. I assume it should be okay but I'm just curious and wanted to verify with some folks here

Thanks

Notes:
Anyone here wants to sell their Mark IVB head shell ??? PM me please

 

[sduck]

You can leave them if they're working.

 

[boucivicsir]

hey there
1st post.
i just got a mark 4 medium head this week end. I really like it so far. Bought it used but it's very clean, not cheap

I emailed mesa customer service and i learned that it was made on july 30 1993. serial # is IV-006496.
It looks to be an hybrid in between the two revisions. It has the non removable ac cord. BUT it's got the revision b look at the rear. (and had the 12ax7 in v4). I also asked them if it was originally an head a combo or a rack mount because some things dont match. But its checks out as a head.

I'll post a picture soon.

thing i wish it had; a wicker front grill.

edit : when i got it, it was retubed (preamp only) with TAD 12ax7 in every position. I rolled every tube except the v5 and NOW we are cooking. The TAD tube were sounding like 'chime'.. add not enough gain for my taste.

now it looking like this :
v1: electro hamonic
v2em mesa (one of the the backup ones)
v3:jj
v4:sovetek lps
v5: tad select.
output = all 6l6
outers = mesa grn
inners = org gray (dont remember.)


now i wish there more difference between r2 and r3 lead.

 

[bgh]

Just realized I had never posted a picture of my Mesa amps.