The Mark IV thread....!!

[stephen sawall]

My guess is 1991/ 1992.

[misterbee]

That's what I assumed. Much thanks

[Ashstrodamus]

My Mark IV B has serial #006703 and found the date on the PC board 7-9-93. Just how early is that for a IVB I wonder?

[ShredPowLines]

Hello all!

Brand new member of the Mesa Boogie Clan, as I picked up a Mark IV wide body combo amp locally at a very shocking price. Externally thing looks mint and sounds great at low volumes. I haven’t had the opportunity to really crank the volume up yet. Bought from original owner who claims he used it 50 hours tops in a studio environment. I’m inclined to believe him based on our interactions. It looks absolutely mint and sounds fantastic. Serial # is 009XXX. I believe it to be a rev B based on reading this entire thread in giddy anticipation of powering the beast up.

The tubes are original but have little mileage on them. What concerns me after researching the amp tirelessly is the filter capacitors. Do you think I need to replace them to avoid them failing and damaging the amp or should they be good to go with such little mileage on them? This thing has just been collecting dust and I’m worried that that will make the capacitors more susceptible to failure... any help would be greatly appteciated, as this is the first tube amp I’ve owned that’s over 5 Watts.

[stephen sawall]

I bought my Mark IV new on the first run in 1990 and have not replaced the capacitors. This one and a few others I should probably look at.

[ShredPowLines]

Update:

I contacted Mesa directly and they said it’s be another few years before I should be worried about replacing caps. Said boogies from the 80’s are starting to come in for cap replacements but hey haven’t seen many of any mark iv’s sent in for cap replacements

[bgh]

Update:

I contacted Mesa directly and they said it’s be another few years before I should be worried about replacing caps. Said boogies from the 80’s are starting to come in for cap replacements but hey haven’t seen many of any mark iv’s sent in for cap replacements

Good to know. Thanks.

[Thaymz]

Hi all

I bought a mark IV which is on it's way. It is a rev B with the shorter curved faceplate and I've noticed the faceplate has "notches" taken out of the corners. It's certainly not a design on the A, and I think I've seen it on some B models but not all but it's hard to tell from some pics as it's usually dark around that area. Anyone have this on their rev b? Anyone know why some might have it but not others? The serial is in the high 7000s and its a 240v.

It's visible in this video. Couldn't find many pics that show it clearly.
https://www.youtube.com/watch?v=0vrzt45mVYo

[El Rey]

[Monolith]

My Mark IV B has serial #006703 and found the date on the PC board 7-9-93. Just how early is that for a IVB I wonder?

AH! My Mark IV short head doesn't have a serial number. It is a ghost head. Should I be able to find a year on the PC board as well?

Also, I have been reading about KT77 tubes and how they are very similar to el34's. Has anyone put Kt77 is the outer sockets of their Mark IV?

[Ashstrodamus]

My Mark IV B has serial #006703 and found the date on the PC board 7-9-93. Just how early is that for a IVB I wonder?

AH! My Mark IV short head doesn't have a serial number. It is a ghost head. Should I be able to find a year on the PC board as well?

Also, I have been reading about KT77 tubes and how they are very similar to el34's. Has anyone put Kt77 is the outer sockets of their Mark IV?

A lot of Boogies were dated in black magic marker somewhere on the amps. Yours should have one somewhere I would think. My Simul-Satellite is also dated in black marker but can't really remember where at the moment.

As far as tubes go, I've always stuck with all 6L6's. Simul-Satellite was modded with an adjustable bias pot for the outer EL34's, but I had my amp guy adjust it back to all 6L6's. Previous owner said he put the mod in to push the outer EL34's a lot harder. Anyways, the pot remains in the amp....my amp guy said it was a professional mod.

[domglop78]

Friends of mesaBoogie, Hello....

I have a mark IV B (series nb: 007307)
my opinion: this is the best amp for combo's production.
Full setup for all kind of sounds. I set up 6l6GC RUBY and 7025 RUBY to get a bluesy and singing sound.
My configuration is visible as an attachment. the front-side settings are also attached.
In the loop send/return I placed for simply chorus effects, detune a GNX4. I kept it just for that because I don't want to sell it... I

general configuration[https://i.imgur.com/q0MObXU.jpg]
conf1[https://i.imgur.com/AoZ9f8t.jpg]
front view [https://i.imgur.com/7qXd3T5.jpg]

recently acquired a Mark2 B (series nb: 9216) 60/100 W with graphic equalizer and reverb.
The power tubes are 6L6 GC JJ. (photo attached)
I saw that there are jack inputs/exits on the chassis !!! Can someone tell me
what they're all about and what kind of footswitch i can use ?

Mk2 [https://i.imgur.com/nMELIH0.jpg]

Thank you for your comments....
my set:
https://i.imgur.com/yONZvpE.jpg
https://i.imgur.com/xdrEvLx.jpg


Dom

[stephen sawall]

When the Mid Gain / Harmonics switch is set to Mid Gain does it make the circuit similar to a IIC++ and III++ ????

[domglop78]

Hello
when i switch into the position Mid Gain there is not really a big difference....
perhaps little more sweetness....

dom

[stephen sawall]

I'm more interested in the circuit similarities ?

The evolution of the Mark series.

I have been looking at the similar circuit on the various Mark and Rectifier series.

Like the Presence pushed in on the Mark IV is similar to the Red on the Rectifier in that it is bypassing the typical depth and presence controls on most amps.

I'm looking at how Randy over time devolved different circuits and how they showed up on various amps.