Bought a Mark VII!

[mace]

Holy heavy hardware. I have a 1x12 Thiele with the 12L and it’s a backbreaker.

Since this is a Mark VII thread of sorts I’ll add that I’ve gigged with the VII combo 3x so far and it has been absolutely wonderful. It sounds so full, so aggressive but not scratchy. This is for light rock to hard rock, hair metal stuff. I’m loving this amp.

In comparing it directly to the V it seems the biggest difference is the VII has more low end thump. This was using a 2x12 Recto V30 cab dialing in IIc+ and IV modes, with the same dial settings, the VII has more low end. The amps sound similar on their 90W settings using Crunch, IIc+ and IV but to my ears the VII is less fatiguing after extended use. Maybe I’m still in the honeymoon phase after only 6 weeks but it is my go-to amp right now.

 

[bandit2013]

it must weigh a TON.

It only gained weight for what I had to add to secure the baffles. It was on older cab and the center post broke off on me and I could not reuse it. Had to add some additional support as the top baffle was loose and would vibrate. The EV speaker is only 9 lbs heavier than the V30, not that it really makes a difference as the cabinet is heavy enough. Not sure what it weighs now, probably closer to 145lbs vs the 104 lbs. The extra 5lbs is due to the added reinforcements, not needed if the cab was in good shape. I doubt I could lift it by myself without injury (at my age) to stack onto a straight 412 cab (something I do not have nor plan on getting any time soon).

What I found amazing was the widebody 112 open-back cab with the EVM12L classic. That speaker just works well with the Mark VII or the JP2C. It was not bad with the stock MC90, but my luck with those speakers has been low. The EVM12L with the Mark V90 emphasizes the boxy characteristic of that amp so it is a no-go. It just sounds sterile, I had the same response with the Mark IVb. The Mark III was great with those speakers as that was what it had stock but the Mesa black shadow version.

I am looking forward to getting the Mesa boogie 4x10 open back cab, will be sometime near the end of the year but it could be pushed back until 2024, just depends when SW gets them in. That may be a surprising change to the vertical 212 cab.

 

[dlpasco]

...I have an EVM12L. I may have to try it out with the VII.

 

[dlpasco]

Since this is a Mark VII thread of sorts I’ll add that I’ve gigged with the VII combo 3x so far and it has been absolutely wonderful. It sounds so full, so aggressive but not scratchy. This is for light rock to hard rock, hair metal stuff. I’m loving this amp.

I'm glad to hear that you're having a good experience with it

 

[bandit2013]

...I have an EVM12L. I may have to try it out with the VII.

If you have a spare cab, that may work. I found with the Mark V and the Mark IV combos, I had to mod the grill just to get it to fit since I could not use the rear baffle mount method and retain access to the removal of the tube shields. I know the IVB and V are different layout and the preamp tubes were more central to the chassis. The EV speaker basket will be more in the way.

I did a front mount on the Mark V90. Needed to sand out the circular opening since the basket did not fit through it. Drum sander powered by compressed air but low RPM so I do not dig into any given area with the sanding drum. Painted it flat black after sanding so if I returned back to the MC90, you will not see the raw wood. That is an Organic Timbre speaker. I did add some foam pads to prevent vibration on grill frame. The 4 stand-off screws were not enough. Much easier with a wide-body cabinet vs the traditional small size cabinet.

Replaced the OTR with the EVM12L classic. The OTR has more midrange and less treble than the EVM12L.

To secure the speaker, it is just with screws, washers, and nuts. No T-nuts as that takes out too much wood, especially around the baffle opening. If I remember, the 10-24 cap screws (type that uses an allen wrench vs a Philips or flat screw driver) Flat washers, and locking 10-24 nuts. No need to use all 8 holes, the 4 screws already there can be removed and use those holes. Those are #8 screws and the length of the screw may not be long enough to get through the thick gasket on the speaker and have enough room to get the nuts on them.

So doing a swap in a Mark VII combo may be more work than you expect. Just keep that in mind. Since the Mark VII combo is much smaller, closer to the traditional size of a Mark III combo, not sure how the EV speaker will fit. May not be a good idea.

 

[dlpasco]

I put mine in my V combo as well You did a much better job on your's than I did.

Yeah, I'm not sure what mounting it in a VII combo would entail yet.

 

[bandit2013]

I should take a picture of the back of the grill, I did it by hand using a router with a 1/4 inch bit. Compressed air to get all the wood dust out and ready to go. Took about 30 minutes as I had to test fit the grill. Not recommended for someone not familiar using power tools in such a manner.

 

[playingitloud]

@bandit2013

I was going through my collection of preamp tubes and I was wondering if I should place these preamp tubes in my MKV or MKVII.

Here is the type of tubes:

Two NOS Mesa SPAX tubes (the ones with the rubber on top) where one of them is from the 80's.

Also, a Tungsol.

 

[bandit2013]

Not sure if that would be good nor not. And which amp to try it in.
Would the 80's tube be a tungsram ? I am not sure when Mesa brought in the Chinese 12AX7 (6N4-J). those were stock tubes in my Mark III I bought in 1989. Still a good tube though. If you have two of them, V4 and V5 would be my choice in the Mark V90. Helps to reduce flub, sounds much tighter in the low end, but that is with the Beijing Square Foil getter tube (6N4-J). TungSol in V2 of the Mark V also improves CH2. Not sure what tubes to explore with the Mark VII. Review your warranty, I think it includes the preamp tubes and not just power tubes. Doubt there would be any issue with preamp tubes as the Mark VII does not have any cathode followers (assumed) Not sure about V2B triode. It could be a plate driven gain stage with just your typical voltage divider circuit for the FX send level or it could be a cathode follower stage like a Recto or Badlander.

I am still curious why each of the channel volume pots are dual pots. Two circuits so is one a pre-FX and the other post-FX? Would love to see the general schematic on the VII, don't need the relay control circuits just basic stage design and how the controls are used.

 

[playingitloud]

@bandit2013

Yesterday, I had noticed a plastic burning type of smell while playing my MKIV then today a power tube went red.

Once I had noticed that a power tube started glowing then I turned off the amp.

I had let it cool down long enough so that I could readjust the power tube positions (I had recently moved the MKIV from one rack to another rack case and I figured maybe the tubes might have moved out of the socket a little bit).

I had turned on the amp again and waited a few minutes then turned standby off and the amp shut down (probably blew a fuse).

Does anyone know where to order replacement fuses for the MKIV?

The manual says:

The FUSE should be a 3 amp Slo-Blo for use with 100 or 117 volt A.C. Mains.

However, the back of the amp says 4 AMP S.B. so I am a little more than confused here.

Thanks ahead of time for any help!!

 

[bandit2013]

What was on the fuse ends, it should be stamped on one of the metal ends with the amperage.

Go to digikey. Better pricing and you can buy in bulk just the one fuse. Most places in my area sell a mixed variety of fuses. Lucky to get one 4A slow blow in with 7 or 9 other fuses you would never use.

Digikey part number: F1768-ND

https://www.digikey.com/en/products.../778305?s=N4IgTCBcDaIGIEYDsA2AHAWgHYBMQF0BfIA

 

[bandit2013]

My bad, it is a 3A slo blow. I could have sworn my mark IVB had a 4 amp fuse. I sold it long ago so have no means to compare it. It should be a 3AB/3AG size. This is the 3 amp version.

https://www.digikey.com/en/products/detail/bel-fuse-inc/3SB-3-R/1009736

 

[playingitloud]

My bad, it is a 3A slo blow. I could have sworn my mark IVB had a 4 amp fuse. I sold it long ago so have no means to compare it. It should be a 3AB/3AG size. This is the 3 amp version.

https://www.digikey.com/en/products/detail/bel-fuse-inc/3SB-3-R/1009736

It looks like Mesa Boogie has used 3A fuses for some versions and 4A on other versions.

I had found that the fuse says 4A on mine so your first link will be the right one for me, thanks.

 

[bandit2013]

It looks like Mesa Boogie has used 3A fuses for some versions and 4A on other versions.

I had found that the fuse says 4A on mine so your first link will be the right one for me, thanks.

There were some changes made between the Mark IVA and Mark IVB. The online manual is more generic than model specific. Too bad there is not one for the Mark IVA and one for the IVB. Not sure but I do recall some Mark IVB were in the smaller chassis before they changed to the wide body format.

 

[Joey1970]

Not ALL respects. While the VII definitely does some great things and excels for home use it's not perfect. The attack is mushy & undefined, the sound has no push and heavy playing completely disappears in the live mix. I really enjoyed mine till I played it next to my vintage Marks in the band, then I sold it the next day.

It's hard to beat the 105 PT and Sylvanias loaded up Mark 2 or 3.

 

[Joey1970]

The guy that I had purchased the MKVII from back in April/May (he had it about 6 weeks) decided to sell his JP-2C last week so I purchased it from him since it was only about six months old and still looked brand new.

The JP-2C definitely has a killer tone.

I think it might have a slightly thicker tone than the MKVII and a little less compressed (I didn't feel the MKVII sounded compressed but the JP-2C just sounds a little more open to me right now).

The clean is really great on the JP-2C (a thick clean tone) and I might like it better than the clean on the MKVII which I thought sounded pretty nice as well.

I've only played on the JP-2C for about an hour here and there so time will tell if I like it more than the MKVII.

I don't see myself getting rid of either amp since they both have their place for different tonal options.

The JP-2C should feel a little more punchy in the low frequencies due to its 60/100 style power section.

 

[bandit2013]

The JP-2C should feel a little more punchy in the low frequencies due to its 60/100 style power section.

And yes, the JP2C rips quite well with the STR415 Sylvania tubes. It may not have the 105 transformer but them NOS tubes are the way to go with the JP2C if Mesa still has them. They are hard to get. The alternative would be the STR448 in grey bias color. The STR445 in green also sounded similar.