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Well even if they are not used in 45W mode they are still on and certainly they could effect the output.
AFA as the same not sure, but maybe @bandit2013 knows .
Mark VII power tube colours
- Thread starter Voyager72
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AFA as the same not sure, but maybe @bandit2013 knows .
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I think 1 foot is good but if you need smaller I found this one
https://www.amazon.ca/CyberPower-GC...=6+extension+cord,electronics,64&sr=1-10&th=1
The trick with the Mark VII, the center class A are wired as pentode for that extra power. Very similar to the Mark V center class A tube spots. Sine Mesa made this a power function so they can drop to 25W power wired as triode, they sort of took away some advantages of the Mark IV and V with the removal of the triode/pentode switch. If that holds true that pentode wiring provides 45W and triode wiring reduces to half power, the Mark V will do that in CH3 in the 45W mode, triode for 25W (assumed) and 45W in pentode. I guess the IIC+ reissue is more of a blend of the 25W triode and 45W or 50W of the Class AB combined.
Peak power of the Mark VII is impressive. At 90W it peaks to the same level as the JP2C at 100W and with similar volume levels dialed in. This will be in the range of 145Wrms peak power. The 45W mode peaks at 70Wrms and the 25W mode is around 40Wrms. I did want to borrow the storage oscilloscope with power analysis function just to see how accurate the load box is. That just uses a few LED lights to indicate peak power.
Peak power of the Mark VII is impressive. At 90W it peaks to the same level as the JP2C at 100W and with similar volume levels dialed in. This will be in the range of 145Wrms peak power. The 45W mode peaks at 70Wrms and the 25W mode is around 40Wrms. I did want to borrow the storage oscilloscope with power analysis function just to see how accurate the load box is. That just uses a few LED lights to indicate peak power.
I have several SSS guitars. Only one is a Fender (Dave Murray Strat), the others are Carvin Bolt and a Warmoth build I did. I swapped out the pickups with Zexcoils. The Dave Murray and the Warmoth have the Juicy bucker types which sound like single coils at reduced volume but will ramp up to PAF characteristics at higher guitar volume. The most recent conversion I did was the Carvin Bolt. This was after the install (note: I do cut the strings once I have the guitar dialed in as I do not like the whiskers poking me in the eyes). I was surprised how good those pickups sound. I believe I was more eager to run this guitar with the California Tweed and probably forgot to go any further with it. These pickups are humbucking in a different manner than a dual coil type is. So far this is the best Strat sound I ever heard to date. I went from SD "evertying axe" set to these. Before that I experimented with many other pickups like Lace Sensor golds. several different strat models from SD. With the Warmoth guitar, I first tried out the David Gilmore EMG set. then changed the pickups to other variations. Just did not like the end result, tried the Fishman Fluence and they were the worse. That is when I found Zexcoil and from there they were that satisfying it remained as is.
Here is the Warmoth guitar with Zexcoils, they are all more or less a PAF style as I was not sure what to start with. I soon discovered the litmus test amp for single coil testing. It is not the JP2C as that amp made every pickup choice sound really good. It was the TC50 or the TC100. It either sounded like crap, to total dog poop (fluence ice pick) or something of value. Considering the space I run the amps is now vacant (feel like I somebody broke in ant took my gear, never happened) I should extract the TC amps out of the closet and run at least one next to the Mark VII. Interesting that the TC has come up a few times this past week. Makes me wonder what its life expectancy is on the Mesa tone farm. I believe they already killed the MW but is still on their website in the perpetual "out of stock" status. The TC100 has that status as well and for some time now. Will there be a reissue Stiletto? Not trying to start any rumors.
Here is the Warmoth guitar with Zexcoils, they are all more or less a PAF style as I was not sure what to start with. I soon discovered the litmus test amp for single coil testing. It is not the JP2C as that amp made every pickup choice sound really good. It was the TC50 or the TC100. It either sounded like crap, to total dog poop (fluence ice pick) or something of value. Considering the space I run the amps is now vacant (feel like I somebody broke in ant took my gear, never happened) I should extract the TC amps out of the closet and run at least one next to the Mark VII. Interesting that the TC has come up a few times this past week. Makes me wonder what its life expectancy is on the Mesa tone farm. I believe they already killed the MW but is still on their website in the perpetual "out of stock" status. The TC100 has that status as well and for some time now. Will there be a reissue Stiletto? Not trying to start any rumors.
Mark IIC+, III, IV, V and VII. Don't want to leave anyone out here, when running in Class A power mode (excluding the pure class A power of the V90), the Class AB tubes are cut-off completely as the cathode is disconnected from circuit ground, so no plate current will be provided by those pair of tubes. The heaters remain active, no point in turning them off, especially if you have a different power mode set for one channel. Both the V and VII have selectable power modes for each channel. Forgot about the IV if it had selectable power modes but the IIC and III did not, it was a universal choice to turn off the Class AB pair only to find out the amp sucks in the 15W power mode. Sorry for those who like that 15W of EL34 power, it is just my opinion.
However, when running in 90W mode, if one tube craps out or red-plates, it will result in overdriving the other tubes. The output power transformer is fed by a center tap of 448VDC. There are two pairs of tubes on each end of the transformer windings. In order for this thing to work it is a push-pull function as directed by the phase inverter tube. the one set is Class AB, meaning they operate in two modes, Class A when not pushed into distortion and Class B once they begin to clip resulting in cross over distortion. What many call the Class A sockets or tubes, are use much in the same manner as the Class AB tubes. They are just operating in Class AB mode but with extended Class A operation and is still a push-pull function. When one tube on one side overloads and draws excess current, the opposing side will suffer the same and will also tend to run at a higher plate current assuming you are getting any sound. The other tube next to the one that failed is not drawing any current as that is pulled from the failed tube. Sound will cut out as you basically turned the OT into a saturable reactor such that the DC current is swamping out the AC signal transfer from primary to the secondary winding. Once you hit the thermal overload in one tube, the likelihood the tubes on the opposing side are compromised as well. If for any reason the fuse fails to blow under this operating condition, the chance of damage to the OT is possible as the varnish on the windings will degrade or crack resulting in coil shorting as the OT begins to reach unbelievable temperatures so hot you cannot touch it without getting burns. Yep, that is what my Mark V90 did all the time. Still not the reason for the ice pick tones, that is related to something else. When I got my first Mark VII, and being told it sound much like the Mark V90, my thought of that nightmare came back seeing the size of the power transformer, my initial thoughts were "here we go again". So far the Mark VII has been quite reliable and not a tube amp toaster like the Mark V90 has been. Too many bad memories of the Mark V90 dread. Reason why I call the Mark V90 I have the Yule log special. It is a Christmas tradition now that I have that amp, feel cold, just fire it up and watch it fail. Yay. Sorry, I will get off of the soap box.
Try it and find out. The SPAX7 is the same tube as the Mesa branded 12AX7 that test in the high grade range with a slight less gain. They heat shrink the glass for some better noise reduction. I never felt they sounded any better than the stock version.
I found the JJ frame grid E83CC tubes to be an improvement over the JJ ECC83s (what Mesa uses). Lower noise floor, a hint of more gain and tone response is a little better. They look identical to the ECC83s since the box plates are the same, it is what you cannot see that has changed.
I found the JJ frame grid E83CC tubes to be an improvement over the JJ ECC83s (what Mesa uses). Lower noise floor, a hint of more gain and tone response is a little better. They look identical to the ECC83s since the box plates are the same, it is what you cannot see that has changed.
Yeah I tried the SPAX7 in the Mark V90 for a couple weeks, didn't notice much difference.
Thanks for the tip about the JJ E83CC.
