Taken from another post:
NOTE FROM THE AUTHOR: Douglas West A.K.A Tone Boy
Randy wanted me to give this bit of info to you personally, even though it felt a bit funny to write “I” as opposed to “we”, so that my personal experience could validate the source.
From 1982-1991 I was the person who tested every finished amplifier here at MESA - along with my other duties in R&D, Customer Service and writing Owner’s Manuals. I worked side by side with Randy (playing guitar and asking for more Tone and features) on the revision of the MARK II B that would eventually become the MARK II C+… as well as every amp since. During that time is when I was affectionately given the nickname Tone Boy for my relentless pursuit of a certain attack/morphing-harmonic characteristic I was hearing in my head. I was driving Randy crazy then - and I must take the time here and now to give him my deepest thanks and utmost respect for listening to my ranting and raving. He didn’t even play guitar - but he heard me - and had the belief in this quality I described just as deeply as I did. And even better - he found a way to deliver it! From myself, and all of us guitarists who have made this sound our own…Thank You!
Anyway, as to how this affects you as a MARK V owner, there is some inside info you need to know to get the most out of Channel 3. This especially applies to you MARK II C+ and MARK IV owners who will be looking for your old amps sound in this Channel and probably even be comparing the MARK V side by side to your II C+ or IV.
Back when I was testing II C+’s every day in the burn-in room, I always thought the non-graphic amps had a certain attack and purity to the sound that the amps that had Graphic EQ on them just didn’t have. There was an urgency and bold punch to the sound…they seemed tighter and more cohesive. Now granted, we made far more amps with the on-board EQ than without…probably 70% had the EQ, but not many people had the opportunity to compare day-in and day-out as I did. The EQ model had the shaping advantage…no doubt about it, and certainly all the sounds that II C+ are famous for were created with the EQ being an integral part of that sound, but when it came to the straight sound – no EQ – the non-graph model always got to me with it’s speed and authority.
So it was that I came to be the obsessive/compulsive owner of no less than 8 of the II C+ Simul-Class, Reverb (non-graphic) heads. I hand picked these as being the best sounding amps - for me - out of the thousands of II C+ we made. Out of these eight amps I immediately found my favorite - which I dubbed “His Highness the C-ness” and which I used as a reference model to have our Chief Tech and Archival Guru Michael Bendinelli, copy exactly on the other 7 amps. Everything was measured and scrutinized (pot values, resistors, caps, transformers swapped, etc.) and duplicated, and in the end… all 8 sounded alike. Regardless, His Highness was my golden reference for MARK II C+ Tone and our R&D reference amp for many MARK Series amps to follow, including the MARK IV.
Over the next two decades I found the need to part with some of these magic amps for studio gear and such and always I gave my close friends first crack at these – but His Highness remains to this day a mysterious, sweet-singing, fire-breathing beast of an amp.
So naturally when it came time to do the Channel 3 sounds of the MARK V, we went to the Oracle – His Highness The C-ness - and asked permission to pay our respects to His Golden Tone…He granted, and the work began.
In our endless comparisons of many original II C+’s - both EQ and non-EQ samples - alongside this golden reference, we discovered that I wasn’t just Tone-dreaming. There was actually a difference between the EQ model and those non-EQ models. It all came down to a coupling capacitor at the end of the EQ circuit that feeds the driver. In the EQ model, it was a great big cap that let a lot of sub-low pass, slowing down the sound and making it fatter. In my amp - a non-EQ version - this cap was smaller and didn’t let as much sub-low through - which speeds up the sound and makes everything tighter and more urgent. There it was, a simple part…but it made all the difference in the time domain.
Yet there were so many more of these slower, fatter sounding EQ versions out in the world… that many more people were used to
THE CHANNELS: (Continued)
hearing as their reference. It would not do well to set the MARK V permanently to this faster, tighter way. Too many players would have a tough time adjusting and when they compared the two amps side by side, the V would sound faster and tighter yes, but also stripped of sub-low and therefore maybe not as fat in comparison to their trusty II C+ Graphic model or MARK IV - which also had the bigger coupling cap. What to do at the crossroads? What we do is take more time… and go down both roads.
So in the MARK V we gave you both fast and fat.
The II C+ Mode in Channel 3 uses this smaller coupling cap to deliver the tightest attack and fastest response in the time domain. In addition you get the bonus of having this Mode work incredibly well with the EQ, because the lack of sub-low at the end of the preamp means you can add more low frequencies with the EQ before the sound gets flubby. So all you II-C and MARK IV guys might like this characteristic even better. You can get high gain sounds with the EQ even tighter than ever before!
The MK IV and EXTREME Modes utilize the bigger coupling cap to add sub-low and slow down the attack for a bigger, fuller slow-hand feel that is absolutely huge. You will find that you have to be a little more careful with the 80 and 240Hz Sliders when dialing in low end with the EQ because more low end happens earlier, but the sound is definitely bigger.
So if you want it tight, urgent feeling with the fastest attack and maximum focus, use the MK IIC+ Mode. If you want the fattest, warmest,
biggest sound and don’t need the super fast response, use the MK IV and EXTREME Modes.
Oh, and by the way…Mission Accomplished! The Oracle, His Highness The C-ness, now shares the Throne Of II-C Tone with the MARK V. Of course the MARK V rules in so many other sonic Kingdoms that it has it all over the II-C for all around diversity of sounds and incredible gig-ability.
NOTE: II-C+ and MARK IV OWNERS
If you do end up doing a side by side with a II-C+ for the LEAD Mode, you must use the II-C+ and MARK V set like this for a fair comparison:
SET II-C+ As Follows:
VOLUME (Far Left) control Pulled (Bright On) and set to Approx. 7 ¾. (This stage in the MARK V is set to a sweet spot we found from measuring many amps and control deleted).
LEAD DRIVE Control Pulled and set to desired setting
All Tone Controls set by ear as close as possible (we measure each pot and set both exactly with an ohm meter).
PRESENCE set to desired setting. (0 or 10 is the most fair for comparisons sake and removes any pot variance).
GRAPHIC EQ Off (Bypassed)
SET MARK V As Follows:
GAIN control set by ear and relative “clock face” setting to II-C LEAD DRIVE.
Tone Controls set by ear and relative “clock face” setting as II-C Tone Controls. (Remember that II-C BASS control is in the 2nd position
- MID is 3rd on II-C whereas MARK V is TREBLE, MID, BASS).
Channel 3 BRIGHT switch in the BRIGHT (switch down) position.
Rear Panel Channel 3 TRIODE / PENTODE switch set to TRIODE (switch down).
Rear Panel EFX LOOP switch set to ACTIVE (switch up).
CAUTION: The EXTREME Mode is LOUD in both these amplifiers…Use Care and Zero out the OUTPUT Level Controls before beginning this comparison
SET MARK IV As Follows:
Channel 3 (LEAD)
LEAD GAIN (FAR LEFT) Pulled and set to 7 ¾
LEAD DRIVE Pulled and set as desired
Channel 3 (LEAD) Tone Controls set as desired.
Pull All Controls (unless comparing EXTREME - then leave LEAD PRESENCE Pushed In = EXTREME)
PRESENCE set as desired (0 or 10 is most fair and removes pot variance)
Rear Panel TRIODE / PENTODE switch set to PENTODE
Set MARK V As Follows:
Channel 3 set to MK IV or EXTREME Mode (Make sure set the same as MARK IV)
GAIN set to match relative “clock face” setting of numeric LEAD DRIVE setting on MARK IV.
Channel 3 Tone Controls set to match relative “clock face” settings on Mark IV.
Channel 3 BRIGHT / NORMAL switch set to BRIGHT (switch down).
Channel 3 PRESENCE set to relative setting on MARK IV.
Rear Panel TRIODE / PENTODE switch set to PENTODE (switch up).
Rear Panel EFX LOOP switch set to ACTIVE (switch up).
You cannot hear the MK II C+ Mode in the MARK V’s response in an older MARK Series model because the coupling cap at the end of the EQ in those amps is simply too big and is adding too much slow-lows to be a fair comparison.
NOTE: These comparisons are as close as possible regarding the setting and configuration of the circuits. When doing these types of tests it is important to take into account that the power tubes, preamp tubes, transformers and even the caps and resistors may be different depending on availability at the time of construction