NADT: Mesa Mark IV content and questions

[philb]

Congrats! I have a Mark IVB that I love!!

Yup, so do I!
I've had it for 3 years now and it's not going anywhere.

 

[blackba]

There are mixed thughts on EC caps. The bottom line is they dry out over time. They have a five year shelf life. When used regularly, they can last quite a while. Most reccommend to change them after 12-15 years. they can do alot of damage if they fail. Some sighns of wear are bulging at one end, or leakage. I am fairly handy with an iron, so I figured why not. I actually enjoyed doing it. I was able to easily lift the power board up and replace the 2-220uf by only needing to desolder one wire. The 3-30uf caps I desoldered from the top of the board and soldered the new ones in. I also replaced the smaller caps as well. I completely removed the old leads. Job came out perfect. I did notice a difference in the bass and punch of the amp. After 18 years they surely dried up at least a little. Another thing that made a huge difference was putting in a super hot mixed quad from Eurotubes. My 6L6's are reading at 37ma, and the E34L are biasing up to 18MA(Which is alot for this amp) Sounds killer.

Its good to know its not too hard to do, I thought the mark IV might be a pain, due to all the stuff in there. I have changed the Electrolytic caps in my Vintage amps (60's), but was going to wait another 10 or so years before I thought about it with my Mark IV or Marshall Silver jubilee.

I thought you might have noticed your caps leaking or bulging. I have heard that modern electrolytic caps should last longer than those used amps in the 50's, 60's and 70's. I think if we did a poll on those who had changed Electrolytic caps on amps that are 1980 or newer, the percentage would be pretty low for those who have changed them. Maybe that makes most people ignorant, not sure.

 

[stephen sawall]

I am the original owner of the 12th one made. (I payed for it over a year before I got it). #68 is from the first run in 1989. I had mine open a few years ago and the caps were fine .... I have not replaced mine yet.

 

[RJF]

I just received my Mark IVB and am NOT meshing with it at all.

 

[stephen sawall]

I just received my Mark IVB and am NOT meshing with it at all.

The IV is one of the easiest amps to get bad sounds from. I would look at how others set it up to get you in the ball park.

http://www.grailtone.com/tone-settings/ ... ings.html#

The EQ settings well make a huge difference.

My settings are on this page .... if you set it up like this .... then just slide up and down the 750 it is not a bad place to start, I also drop the 2200 down often. I use a full stack with it most of the time ....

http://www.grailtone.com/tone-settings/ ... etting=243

 

[richierich]

I got one at a guitar center years ago. Did tons of research before trying it out. Got to guitar center asked to see the Mark IV and the sales dude was like, "REALLY". 5 minutes later he was a believer. Got a great deal on it at the time. This was just before the Lamb of God hype. Poor amp had cobwebs on it. $1000 for that floor model. Sounds especially nasty with an old TC Booster/line driver pedal. I've also found a NOS RFT in V1 works well. Don't skimp on power tubes. They make a big difference in this amp. I think it sounds best using a 6l6/EL34 combo.

 

[glip22]

I got one at a guitar center years ago. Did tons of research before trying it out. Got to guitar center asked to see the Mark IV and the sales dude was like, "REALLY". 5 minutes later he was a believer. Got a great deal on it at the time. This was just before the Lamb of God hype. Poor amp had cobwebs on it. $1000 for that floor model. Sounds especially nasty with an old TC Booster/line driver pedal. I've also found a NOS RFT in V1 works well. Don't skimp on power tubes. They make a big difference in this amp. I think it sounds best using a 6l6/EL34 combo.

The hotter the better. Eroutubes can hook you up with a hot integrated quad. 6L6(Grade 62+) E34L(Grade 50)

 

[blackba]

I got one at a guitar center years ago. Did tons of research before trying it out. Got to guitar center asked to see the Mark IV and the sales dude was like, "REALLY". 5 minutes later he was a believer. Got a great deal on it at the time. This was just before the Lamb of God hype. Poor amp had cobwebs on it. $1000 for that floor model. Sounds especially nasty with an old TC Booster/line driver pedal. I've also found a NOS RFT in V1 works well. Don't skimp on power tubes. They make a big difference in this amp. I think it sounds best using a 6l6/EL34 combo.

The hotter the better. Eroutubes can hook you up with a hot integrated quad. 6L6(Grade 62+) E34L(Grade 50)

I agree, the Mark IV is biased cold, so hotter tubes helped. I actually had a bias pot installed in mine, it didn't make as much of a difference as I expected though....

 

[peterc52]

I got one at a guitar center years ago. Did tons of research before trying it out. Got to guitar center asked to see the Mark IV and the sales dude was like, "REALLY". 5 minutes later he was a believer. Got a great deal on it at the time. This was just before the Lamb of God hype. Poor amp had cobwebs on it. $1000 for that floor model. Sounds especially nasty with an old TC Booster/line driver pedal. I've also found a NOS RFT in V1 works well. Don't skimp on power tubes. They make a big difference in this amp. I think it sounds best using a 6l6/EL34 combo.

The hotter the better. Eroutubes can hook you up with a hot integrated quad. 6L6(Grade 62+) E34L(Grade 50)

I agree, the Mark IV is biased cold, so hotter tubes helped. I actually had a bias pot installed in mine, it didn't make as much of a difference as I expected though....

I actually thought of making my tech do a bias pot. It would make the tubechanging easyer in the future right?

 

[blackba]

I agree, the Mark IV is biased cold, so hotter tubes helped. I actually had a bias pot installed in mine, it didn't make as much of a difference as I expected though....

I actually thought of making my tech do a bias pot. It would make the tubechanging easyer in the future right?[/quote]

Actually no, it makes tube changing more of a pain. To check the bias I have to pull my chassis to get the bias probes in. I also check the bias in all modes, just to be safe. The inner tubes are always biased cold, even with a bias pot. If I had it to do over again, I probably wouldn't install a bias pot. It was in many ways more hassle than what it is worth.

If you don't get the bias pot you can just get power tubes from a good tube dealer and tell them which amp it is for. Doug's tubes for example will set you up with a set that works.

 

[RJF]

I just received my Mark IVB and am NOT meshing with it at all.

The IV is one of the easiest amps to get bad sounds from. I would look at how others set it up to get you in the ball park.

http://www.grailtone.com/tone-settings/ ... ings.html#

The EQ settings well make a huge difference.

My settings are on this page .... if you set it up like this .... then just slide up and down the 750 it is not a bad place to start, I also drop the 2200 down often. I use a full stack with it most of the time ....

http://www.grailtone.com/tone-settings/ ... etting=243

I can see that! I used one of the Mark Morton settings and am getting a pretty good metal tone out of it, but the problem is if I close my eyes the amp sounds almost identical to my 2 channel Dual Rectifier.

 

[stephen sawall]

The IV is very much a Swiss army amp ... it can do a lot more voices than most amps. Because the tone stack is pre gain you want to keep the bass low most of the time. 3 or less for most applications, many like it off or 0. You can get all the bass you want from the 5 band EQ that is post gain.