Mesa Boogie Mark IV - Revision A vs Revision B

[@sheldonswan45]

Mark IV for life! 🤘🏻

[@jameslugo]

I like the A here for sure.

[@williamscolaro1159]

What a sound, both are awesome.

[@YsAbTones]

i agree both have their goodness

[@jameslane3167]

Nice comparison man I love these amps. My buddy has a Mark iv revision b he's selling me in a couple weeks. I can't wait. I'm on the lookout for a Mark 3 black strip also.

[@YsAbTones]

i would go for a black stripe all day

[@jameslane3167]

@@YsAbTones they are a true treasure.

[@washingtonirving2137]

The B is far brighter. Looking at the schematics I see three spots that might be responsible for this; on the 2nd lead stage the B has a larger lead bright cap and is missing a cap between the voltage rail and the plate, then in the phase inverter it has a smaller cap between the differential signal paths. Aside from this and the inevitable pot taper differences, some (don't know how many but mine did) B's have a 200k lead treble pot (not a 250k that measured low) which thins out the midrange a bit. Supposedly also they are running a much higher plate voltage on all of the preamp tubes in the lead mode than the A but I don't really know if this, or yet another difference which is the lead stages being split between two tubes, makes a difference as far as brightness goes. Nice comparison.

[@AA_MusicGuy1111]

So can a B be modded to sound more like an A?

[@washingtonirving2137]

@@AA_MusicGuy1111 ​To an extent for sure it could. But then a problem is posed by the output transformer, which is, if my memory serves me right, different between the two amps (and a decidedly unmoddable component), and the differences in the physical layout of the lead circiut which would be an insane amount of modding to change one into the another, for god knows how much of a result. To mod everything else into the A amp spec would be also an overwhelming amount of work for both a hobbyist like myself for instance as well as an amp which hates being worked on that the IV is. I would therefore remain prudent with the modding, as to not screw up the PCB for instance. Some of the mods don't do much at all (such as the PI filtering, which I infer from some basic circuit simulations), some are impractical due to how the amp is laid out inside (again PI filtering), for some it's mostly a matter of sourcing the right components (lead bright cap and lead treble pot, you could take a pot from somewhere else in the amp though), for some it's a matter of cutting a single LDR leg which might be quite easily reversible (lead mode preamp plate voltages), and some are actually on my list that I want to do (V4A grid leak resistor - it seems to add quite a bit of highs and it is not in a hopeless spot to solder around). Personally I have done some mods on my B by myself and I like how they turned out, but they're all very simple. It's your amp to use and mod, but also your amp to lose if you lift a trace on the board and can't repair it. The fastest way to make the B less bright is to disengage the lead bright switch and turn down the treble slightly.

[@AA_MusicGuy1111]

@@washingtonirving2137 thanks but it’s not just as simple as bright. It’s that the A seems to have more low mid girth and tightness

[@cunjoz]

Thank you for that wealth of Dream Theater riffs (I see you're a man of culture as well) and for this awesome comparison. As I've grown to prefer tones that aren't that scooped because they sound bit fuller to me (wall of sound and stuff), I prefer rev A in this video

[@5150forevermore]

Very interesting. The B sounds a little more scooped and compressed. I liked the Rev A better.

[@ethanspaulding6067]

I agree with this. A has some serious tightness.

[@rockitmanvideos4247]

really good comparison! I have a rev B. To me, REV A is a little more open sounding in the treble zone, REV B is slightly more compressed sounding overall. I think I will keep an eye out for a possible REV A addition to my collection....

[@YsAbTones]

the rev a is seriously great, the rev b is sold

[@giorgosk2884]

A is a bit more raw than b i think which is warmer and less chunky-best for leads and A for riffs

[@fabiol.9161]

I agree... If only in the mark v and vii they could be switchable..

[@francomatera]

Best comparison ever!!!

[@kmanick107]

I have owned both over the years and found "A" to be a bit warmer sounding , but the R2 channel on "B" was much more usable.

[@thrasher10000]

Rev B for me, sounds more full and modern. Although A sounded better through my phone before I got some good headphones ha

[@DiegoAmbrósio-o6m]

Great video! I go with the A.

[@juliochingaling5824]

Great video. I may be the only one to notice, but the Rev B is the black covered, the B has the 2 rockers by the master vol. Vocing and EQ. I had both,still have the B,1996.

[@coreyclark6505]

Those rockers are on the back of the chassis for the short chassis. It isn’t indicative of a Rev A or Rev B.

[@juliochingaling5824]

@@coreyclark6505 kool,good to know. Rock on.

[@Tiger1016.]

What a coincidence, I was just opening up KZbin to search for this exact comparison and this was #1 on my recommended videos list! Very helpful and well done. The Rev A is more in line with what I would prefer. The new Mark VII release reignited my interest in trying out a Mark again. Only used the model of the IV in the Axe Fx, which got me by for ~5 years, then owned a IIC+ for a bit before going all in on a few Wizard amps, but now I'm thinking of trading out one of my Wizards for a Mark. Let me me know if your ever interested in considering in trading the Rev A for a Wizard MTL 100w el34.

[@YsAbTones]

the rev b is just sold, the rev a is definitly a keeper, thx for the proposition you can get in mark series territorry with the boost engaged in your wizard + a mudkiller od or a maxon 808x

[@ultimatemetalguitartones]

I'm interested.. where are you located?

[@Tiger1016.]

​@Ultimate metal guitar tones Hey sorry been on a binge watching tour trying to decide which Mark is going to be the best option for me. Still leaving towards the IVa but also been looking heavily into the VII, just feeling like it is lacking in the ripping attack department although I am liking its different base level EQ and features. Also, have taking another turn with a IIC+ or trying out a III on the list as well. I'm in the US, Texas. How about you?

[@mikerichardson3017]

I noticed that the A has the EQ on but the B does not. That will make a HUGE difference for the comparison between the two amps.

[@YsAbTones]

both were activated

[@sn00k24]

After a while I just stopped listening for the differences and got lost in the awesome playing, both tones are great though

[@worldline7147]

Good work.

[@stevestevens1457]

Is song on 2:06 an original? If not, tell me the name please.

[@YsAbTones]

it's from Dream Theater in the presence of enemies part 1

[@stevestevens1457]

@@YsAbTones thank you!

[@UncleYoshi]

The Rev A sounds a tad nicer, especially the lead tone, very nice milky liquidity sound. What's the major differences b.w a Rev A and Rev B?

[@YsAbTones]

i would say the presence control is way brighter on the B, but yeah the overall grain is more modern/scooped on the b for sure

[@Turboy65]

Tone is so subjective, two people might describe the difference in two ways that are mutually exclusive. I hear very little difference between the two, but I hear the B as pushing the lower midrange a bit more. I'd really like to see high resolution frequency response plots of both amps with the EQs turned off and all controls at 5.

[@YsAbTones]

i tested them with an outboard GEQ with the same setings, the B preamp is a little bit more scooped and agressive, it's a bit tighter too, both really great amp

[@ultimatemetalguitartones]

@@YsAbTones agreed

[@YsAbTones]

​@Deconstruction 33 would advice to dont overthink it too much, at the end of the day it's a matter of taste and we all end up with the one we like (in a particular application)

[@TK96]

Rev A for me it has musical mids.

[@crankyourampupalltheway]

A is better I think. How did you set your ts9 clone? Gain 0, Level max? Is it generally useful for tight rhythm to use ts9 for Mark series amps? What do you think? Your clip sounds amazing!

[@jake13b]

both sound great. sound wise i think i lean more tword the B. what are your thoughts ? i would think the A, having an older transformer, may actual be better in the room and playing.

[@YsAbTones]

i prefered the B overall, but i would take a mark III over both IV

[@jake13b]

@@YsAbTones wow, interesting. any mark iii color in mind ? red seems to be the most sought after. i had a green for a long time, just wondering.

[@torreyintahoe]

I have an A from 91' and a B from 95' and I can barely tell them apart.

[@austinsandefer649]

Wow.

[@nunoharris]

Hi.. whats the year of your amp ? Thanks

[@FEAROWNAGE]

Do you pull back on the gain to get the clear chun chun chuns?

[@YsAbTones]

not really , i use the pull fat only for lead parts (not for rythm), generally i tend to play with just enough gain needed (not too much)

[@fabiol.9161]

The question should be why mesa made these changes from A to B.. What whas the reason in your opinion? They should be set to sound identical with different eq?

[@YsAbTones]

well the power amp/presence/GEQ is way different on each, that said the B can sound close to the A , not the other way around imo

[@dnd820]

Apples to oranges.......Both sound good

[@tomh4244]

Rev A vs Rev B is apples to oranges?? 🤦‍♂️ 🤦‍♂️ That'd be if you compared a mark to a recto, not 2 marks, especially 2 of the same but different revs 😂😂

[@txhc666]

B A sounds kinda dark to me

[@puppet-m]

looks like you have the A&B mixed up on video? My revA looks more like your B and all the RevB iv seen have that light switch over top of each other?

[@YsAbTones]

my rev B was a short head, you can find short heads in A & B revision

[@puppet-m]

iDK that.@@YsAbTones

[@Infineonxdpe132g5c]

But can they sound same? Its a most interesting question… Because if they can, there is no point of trying to get rev that you need…

[@YsAbTones]

no they cant

[@micropaint.limited]

Great comparison! How did you capture the sound? Did you simply use a Shure SM57 microphone and a Mesa cabinet, or something else?

[@YsAbTones]

thx, with loadbox and IR

[@austinsandefer649]

Eat it.😊

[@Astral_Wave]

A

[@lukaszkosakowski1470]

Rev A sounds more natural

[@scription7277]

the rev A is much clearer.

[@depafranko]

REV B