At least with my experience, when the amp is new it can be harsh sounding. The Mark V is a very bright amp compared to many other amps I have or had. At first I had to dial out the presence and treble on both CH2 and CH3, even that did not eliminate the ice pick tone. After 3 years of use, I can dial up the gain, treble and presence to some extent without causing too much pain hearing wise. I did start of with a OS Recto Cab with V30 as my amp was a head. I recently converted the amp over to a combo but will use my 412 cabs I have every now an then with the amp. Also what I prefer is running the amp with two cabs thought he 4 ohm jacks since the tone is not as bright as it is with a single cab or speaker on the 8 ohm jack. The more use I get on this amp the better it sounds even with new tubes it is not as harsh as it was from the first time I used it.
Speakers and or cab style will make a difference on your sound. Dial the amp in with your ear is usually the best method. The factory settings are good guides to get started but learning a few tricks can make a difference. I do have my preferences in amps, my two favorite amps would have to be Roadster and RA100. The Mark V is quite different but yet I can still enjoy the amp at any volume or power setting. The main reason for my change from head to combo was for that rich tone in the clean channel and open back cab, the higher gain channels sound great too, and I can still use my 412 cabs if I choose to.
As always, different types of guitars (pick up type) may require different settings I have several guitars with different pickups (strat sized humbuckers on a strat type guitar with Floyd Rose bridge and bolt on neck, many neck though with humbuckers a few with active tone controls and the rest are passive, and two set neck guitars each having a different tone and character to them).
My favorite is the CH2 crunch mode, 90W, gain almost maxed out, treble at 10 o'clock, mid set to 2 o'clock and bass set to 11 o'clock. Use the presence to dial in to your preference. Also the EQ active in preset. I have used the sliders but prefer the preset for CH2.
As for CH3, lower gain settings seem to work but now I can set the gain much higher as well as presence and treble.
What sets the Mark V from the others, the three different channels do not have the same basic voice. I actually found the Mark V to be easier to dial in when compared to the Roadster or any of the Rectifier amps. That being said, I have only owned Mark Series amps in the past before I got into the RA100 and Roadster amps. If the Mark V is new to you (first Mark series amp) it will take a bit of time to get familiar with the amp. I still have to refer to the owners manual on the Roadster every now an then in order to get some a desired tonal character but when it comes to the V I can dial it in without thinking about it. I was originally after the Roadster but came home with the Mark V since it seemed familiar to me (had a Mark IV and Mark III) and I could not get the Roadster to sound good due to unfamiliarity along with the tech who was helping me choose who was just as unfamiliar with the amp as I was.
You can use the 45W or 90W modes and not be too loud if you use the FXloop set to active and use the master control for volume adjustments. Do not fear the higher power modes, also try the variac power vs the full power as this will cut some of the top end a bit.
