Clark Kent's FW18 Mesa Mark IV John Petrucci Guide

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So me and Irotlas went all in yesterday. We have a Mark IV at our rehearsal space that's all set for the Petrucci tone. EL34s in the outer sockets and running a Mesa 4x12 Traditional cab like the sir himself. We decided we would do the mother of all A/B tests and go through everything! Essentially we wanted to get "that Petrucci sound" so we set the Mark IV like Petrucci:

BottomMK4Settings.jpg


And started comparing what each knob did. F.ex. how every GEQ knob on the amp worked against the USA Lead GEQ page. It took as the whole day but finally we know how to set the amp sim to sound EXACTLY RIGHT! The way we compared this was that we used a Line6 wireless system for the guitar and headphones and we would take turns on who's tweaking and who's playing. The one playing would walk far away so he wouldn't hear the real amp in the room but just the signal of the real amp or the Axe-Fx. At first it was really obvious which one was the real thing. Luckily in the end we got so close that we wouldn't bet money for it. :)

Remember, this is not us trying to tone match anything. We're not going for Petrucci's album tones. What we're doing is turning the Mark IV amp sim to sound just like the real thing with the Petrucci settings.

So first of all the correct amp sim to use for this sound is: USA Lead so not the + or Bright switches. Turn the FAT on which does what the pull fat switch does in the real amp.

Then the speaker page needs a small adjustment for the low resonance. Remember that we were using the same cabinet Petrucci uses himself. 110hz as the frequency. 2.8 Q and 7.00 as the low res amount. That's it. Obviously there's a particular Cab Pack out there that is based on this cabinet so you might want to look into that if you're really into getting this sound nailed. :)

Overall we were struggling with getting the palm mutes correct and I think that's something people in here have been also complaining about a little bit. It's got everything to do with the MASTER VOLUME setting. 4.00 matches Petrucci's settings so leave it there and never touch it. 4.5 screwed it up. 3.5 scooped the sound a made it fizzy. For that right fast attack palm mute of the real thing the master has to be at 4.

The GEQ. We went through it quite thoroughly and realized the small differences. On this particular amp that we had the 2200hz and 6600hz frequencies were lower than on the Axe-Fx. F.ex. 6600hz frequency was around 4000hz but the Axe-Fx frequency was around 5000hz. Don't worry about this. The Q on those knobs is huge meaning that they're wide EQs and the frequency isn't that important and I'm sure the GEQ on the Axe-Fx matches Cliff's GEQ. However on the real thing when you set the GEQ symmetrically it's not actually boosting the same amounts. The real Mark IV had 1-2dB more highs. What we really want to know is "what are the settings for the GEQ in the Axe-Fx to match those Petrucci settings?". Well I've got them for you. +7.00 for 80hz, 0.00 for 240hz (yes... this knob worked a bit differently on the real amp), -6.5 for 750hz, +2.00 for 2200hz and +6.50 for 6600hz.

So now this poor Mark IV has lost it's value. Everyone Axe-Fx owned owns it. :) I'd love to hear how this works for you so please post clips in this thread. I'm really interested to hear them.

Here's an extremely quick clip I put together with my EBMM BFR JP6:


The IR I'm using for this clip is from Cab Pack 7: CK USA Trad SM57-MD421 01
 
MASTER VOLUME setting. 4.00 matches Petrucci's settings so leave it there and never touch it.

"matches" as in visually the same setting as on the real amp (4 = 4)?
In that case a little nitpicking: the Master Volume tapers on the real amps are not matched in the Axe-Fx models. So "4" on the real amp doesn't (necessarily) equal "4" in the model.

Thanks for the guide.
 
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"matches" as in visually the same setting as on the real amp (4 = 4)?
In that case a little nitpicking: the Master Volume tapers on the real amps are not matched in the Axe-Fx models. So "4" on the real amp doesn't equal "4" in the model.

Thanks for the guide.

Master on 4 on amp sim equals output on 3 on the real amp.
 
In reading the post I saw where you said that the MK IV has EL34's on the outer sockets, does that mean that there are 6L6's on the inner? How did you compensate tone/feel? I have been wanting to combine 6L6's/EL34 tone in the Axe Fx since I got it. Also, what tonal difference does it make if any if the tubes are inner/outer sockets?

Thanks for all that you share with us!
 
When I tried EL34's the outer sockets on a Mark III it made for a slightly looser/spongier feel. The outer sockets are wired specifically for this. Do not try EL34's on the inner sockets.
 
Awesome! Think you could add this part in for people so they know what IR CK was using when he dialed it in. I'm not sure how to edit the wiki, or if I'm even allowed to haha.

Done. You should be able to create an account and edit the text. Don't worry about messing it up. If you do, it can easily be reversed. It's a WIKI after all.
 
I'll test your recipe and post a clip here, I had always tension on MV, how much I need exactly, I have strong ears :)...bud I couldn't find it exactly like the real amp,
MV is the key of real amp tone in the Axe, it's very important to know how much it should be, I haven't a real Mark IV...
Boogie Mark IV is one of the most important amps in the guitar tone land... and again it's very good to know how much MV and EQ we need on this model with JP savory tone
 
That's cool! I've been wikied! :) While at it.. Cab Pack 7 was specifically shot because it's "the cab for the USA sims" that's why it's called USA Trad. If someone is brave enough to put it there in the wiki that'd be great. :)

For the measurement process we used an SM57 on the real cab and an IR of that same spot. However that is the cab that was used for Cab Pack 7.

The measurements were really scientific. We did the measurements with Ozone 5 match EQ so we could see exactly what's going on. Tweak until the EQ line is flat and then you can remove that EQ and the tones are practically identical.

Personally I don't have the bass knob on 4 although Petrucci is god and everything. I might have it around 2-3 both on the real amp and the amp sim. I use darker guitars so that could also be the reason why.
 
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