Another New Guy With A Mark V.

[bandit2013]

I would have to admit, before I bought the Mark V I knew little if anything on tubes myself. I just generally bought Mesa tubes for the Mark III and Mark IV if they were available. Come to think of it for the entire time I owned the Mark IV (bought it new in 2000) I never changed any of the tubes until 2012 (this includes the coke bottle 6L6GC tubes, would love to get my hands on those again). Thanks to the ice pick tone of the Mark V, I had no other choice to find out what would work and what does not. I spent the past 4 and a half years looking into tubes, experimenting with this and that. Of course the tube devil urged me to do the same with the other amps.....who could resist.... well as it seems the Mark V takes to different tubes quite well, the other amps, not as expected. In short the Mark V is one amp that can be tuned to taste with preamp tubes as well as power tubes. Wonder what set of tubes were intended to be used originally as Mesa was selling Russian tubes too (EHX 12AX7) early in the Rectifier amps until they found the cathode follower circuits were sudden death to the Russian variants but the Slovokian JJ tubes seems to live much longer. Note that the Mark V has no cathode follower circuits so no fear to be had when tube rolling the Mark V.


In my opinion, if you have a new Mark V, use all Mesa tubes ( but perhaps except V4 as the JAN/Phillips 12AT7 just sounds better, also it is a NOS tube since they stopped production sometime in the late 80's or early 90's, JAN specifies a Military grade such that under duress and harsh environments it will not cause issue in the signal - typically under extreme vibrations at any frequency range. If you know what a HALT test is.... there may be a specific range of vibratory vibrations and temperatures the tube must perform at).

I would probably opt for the Mesa SPAX7 for V1 as the gain and tone of that tube is not has harsh as the standard Mesa 12AX7 (JJ tube). Has a bit of treble cut but still sounds great on CH1 and CH2. Mesa 6L6 power tubes and the Mesa 5U4GB rectifier tube. The Mesa 12AT7 tube tends to add more brightness to the mix on CH3 which does not need it. JAN/Phillips is a warmer tone and still retains the top end chime you need to cut through.

I would consider the same for amps out of warranty. However I may opt for Svetlana in V1 or a Tung Sol as this adds a bit of presence to CH1 without being ice tone. Rest of tubes to be stock except V4 to JAN/Phillips 12AT7 or even other versions of the NOS 12AT7. The JAN/Phillips being more affordable than the Mesa 12AT7. You do not need to get the rare versions of the 12AT7 as there would not be much of a benefit due to the tube position in the gain chain.

If you have desires to change preamp tubes to different types, medium plate or long plate, I would recommend the JAN/GE 5751 for V4 as some of the 12AX7 variants may add more gain at lower frequencies compared to the higher frequency such that the 12AT7 does not sound as good. Still nothing wrong with chasing the tube balloon but can get expensive if you are not careful. I have spend a long time away from Mesa stock tubes in the Mark V but now I actually prefer them ( for one thing they are still available and in current production ) too bad the JAN/Phillips 12AT7 is not. I have not tried the other 12AT7 variants of tubes that are in current production except for the Chinese (Mesa) 12AT7. Note that I have three Mesa amps that use this as a standard tube for the FX loop (two RA100s, TC-50). I found the NOS RFT 12AT7 sounds much better in the RA100 than the Mesa 12AT7. I have not tried the RFT 12AT7 in the Mark V yet. I will get around to it sooner or later. On that note, I found the JAN/Phillips to be a bit brighter in the RA100 so not sure how the RFT 12AT7 would perform in the V.

 

[The Mink]

Bandit2013, I'm going to have a brand new Mark V in the house soon. I have no interest in going down the long tube swap road, especially since my knowledge is limited at best. But I am keen to try the JAN 12AT7 if it's really that noticeable. My tastes lean much more vintage than most My V players; I don't play metal or any shred-related styles and warmth is king. CH 3 will probably end up as my crunch channel. What do you thinknis my best setup?

 

[bandit2013]

The newer Mark V amps do sound really good. Stock tubes are all you really need. However if you find CH3 a bit harsh or too bright, the Mesa SPAX7 will roll off the highs a bit if used in V1 (that will not void warranty) I would personally hold off on any preamp tube swaps or power tube changes until after you break in the amp. Considering the cost of the investment, best not to go into the tube tunnel until after you have explored the amp to its full potential.

I no longer have a Warranty on my Mark V and it something were to go wrong the cost of repair would not be covered. I would look into it for information sake for a future experience. It is not mandatory to do the "saturation mod" out of the box. Chances are you may not even need it.

Just for reference......
The "big to do Saturation mod" is a simple preamp tube swap by replacing the high gain cascaded preamp tube in the secondary position (V4) changes the high frequency characteristic and thickens up the midrange and aids to tighten up the bottom end at the same time reducing the odd harmonics that lead to ice pick tone with the higher gain settings on CH3. It may not be necessary to do this with a new Mark V as many who have done the single tube swap have claimed they do not get the ice pick tone but wanted a change in gain characteristic. Some of us have not been so fortunate with their Mark V and found that CH2 has been more pleasing than CH3. My tone quest has finally ended since I got the JP-2C. One thing to point out, the Mark V is capable of performing on the same level on CH3 if you opt to swap out the 12AX7 in V4 with a JAN/Phillips 12AT7.