Mark IV trouble shooting help

[Boogiebabies]

I hate them due to the problems they create.

Best of luck with your amp.

 

[tim6string]

Problems they create? In an earlier post you said people say they are safe but you wouldn't trust them. It is a load on the amp just like any other load and if that failed I suppose there could be problems. I am pretty confident you could cause problems running the amp wide open which is doable with a hotplate, but I would never do that with an amp. (With or without a hotplate.)

You gave me some great advice early in the post. And I really appreciate that. Tomorrow I am going to dig in and see what I find and report back. Once you heard Hotplate you have made some assumptions that at this point make no sense.

Trust and actual problems truly traced to a load device are different issues.

My guess is a Hotplate may cause problems with an amp to show up sooner due to the fact that it is being used harder, but unless the device fails or the user does bad things with the amp that should not be done, I really don't see how they can be a culprit.

 

[tim6string]

Let's take the Hotplate debate somewhere else. Unless you have any other thoughts, I will go do my homework on the amp and follow your earlier thoughts which will be very helpful and report back.

At this point I believe it is my turn to do some work, everything else is speculation.

 

[Boogiebabies]

Please post where I have ever endorsed a speaker load of any type.

http://forum.grailtone.com/viewtopic.php?t=993&highlight=hotplate


I have had the privledge of working on over 40 amps. I am not some shmuck sitting behind his computer with a huge imaginative ego. If I can learn from someone, I graciously accept it. If I can help, I do. So many players are under the belief that a Mesa must have massive amounts of power tube saturation and rely on a soak. Dummy loads, soaks, hotplates and whatever other type of artificial power absorbtion has an adverse effect on how the amp will sound. Why do most of them have some type of EQ or bright switch. My beef is that most guitar players know squat about the basic principles of tube amplification and they run a soak with tubes until the superb Chinese or Russian tubes wear out in half the normal time and take the OT out with it or heat digital switching componets until the amp does not work in some fashion. Fortunately for me, this is a great public forum that allows a person to speak an opinion as well as facts. I would never disrespect any of the great forum members here and there are a host of well respected members. I would never ask you to take your issue somewhere else.

 

[Antoine]

I think Boogiebabies really know Mesa Boogie amps, just search topics where he has posted and you will see he know a lot about them, he has given me some really precious informations about the Mark IV that i have never heard before, and i know a lot about the IV !
He always try to help, hopefully we have someone with all this Mesa Boogie knowledge here so, i think he deserve respect ! thanks Boogiebabies !

 

[tim6string]

I think you have misunderstood me. I didn't mean not to have the debate on this board, I just thought a different thread.

I certainly never meant to imply disrespect, it is obvious to me that BoogieBabies works on amps and nows a lot about Mesa amps.

I realize tonewise Hotplates are a big debate, people love them and people hate them. I cannot argue that point, it is a matter of taste, different for every player. I like mine. Does it change the tone, it must, because I like my amp better with it. That certainly doesn't mean everyone should go get one.

I don't think I need massive amounts of power tube saturation, but I feel the amp sounds good with the individual channel masters above 3 and the master above 4, that is too loud. I also feel the Hotplate has made the sound bigger, broader, not really sure what the right adjectives are here.
I was also very happy with my sound getting the time based effects out of the loop and after the amplifier. There are otherways to do this of course, but the hotplate solved that problem and the volume problem and I was ultimatly happy with the result.

I don't think a fried amp that has used a load device is direct proof that the load device is the cause, there are a ton of reasons that can happen, one is that the amp may have been used a little harder and problems inheritant in the parts are bound to show up. And I also think that people that do not understand tube amps can easily cause bad things to happen with a load device, they are not fool proof. (And certainly allow someone to do things they wouldn't normally do.)
Amps go bad without load devices also!

A ton of people use them without problem.

And I appreciate all of the advice I got at the begining of this thread, it was knowledgable, logical and gave me information and places to start trouble shooting without going in blind.

I also never meant to imply that you have endoresed the use of a load device, in fact I think you made it very clear that you don't trust them.

Let's not make this personal, I don't believe anyone who has been kind enough to offer advice on this thread is a schmuck and I certainly feel we have a right to our opinions.

My original problem was a One time intermittent thing (which I will have to dig into tomorrow) and once the Hotplate topic came up we have dwelled on that which may in fact have nothing at all to do with what I experienced. (It is always possible it did have something to do with it, not sure how to verify that, but I will post what I find.)

 

[RussB]

It could very well be a switch, and/or a heat related issue. I'll be watching this thread to see how it all turns out.

 

[tim6string]

I just opened the rack, checked the fan, cleaned the switch played for over an hour and all works normal.
No dim LED nothing.

So I have nothing significant to add here. I thought it did it once when I was powering up, so it is always possible it is a bad switch connection, but with the cleaning and all I could never reproduce it.

Seem to be getting that oh so familiar squeel from the preamp tubes, man this thing eats those up. It always has. But I do spend most of my time on the lead channel and I do use a lot of gain.

The rack mount kit has the fan really close and as the tubes go bad it seems to quickly start picking up the fan. Not like in the combo where it was at the bottom.

Final answer ??? It is working fine, so I guess I have to chalk it up to the switch. I gig on Friday, maybe there will be another chapter to the story then.

Thanks for all the input.

 

[RussB]

If it is indeed the switch that's going "bad" it will never start to go "better"

 

[tim6string]

Very true. I cleaned it with some good stuff, with all the smoke and stage fog, I am guessing it will be better if that is truly the issue. Maybe once this string of gigs if over I will have it looked over again. I hate to do a rush on something I can not make happen (because of course there will be no problem at the shop.)

I still want to get another Mark IV as a backup, I hate to play without this. (Just cannot afford to have one laying around) Love the amp!!!!

 

[Tuna141]

Here's a few suggestions:

1. Although your tubes are relatively new, I wouldn't rule them out as a possble cause - especially the power tubes. They can cause some weird probelms. I'd definitely keep an eye on them, especially since you push them pretty hard. You may want to swap the outer & inner pairs to see if the problem follows the tubes in the Tweed/Full power settings.

2 Another thing you can check is your footswitch. If your footswtich LEDs were going dim, I'd try shaking the cable and move the footswitch around to see if the LEDs change brightness. You may have a high resistance short or an intermittent break in the cable or connection. The jack could be oxidized.

3. Was the club's AC outlet holding the amps AC cord solidily (not cauring some intermittency)? Was the line AC stable? Voltage fluctuations can also cause amps to do some weird stuff.

Good luck.

 

[tim6string]

Good input.

I do not use the footswitch, I have an Axess Electronics CFX4 with the Mark IV custom cable so I can MIDI switch the amp. I did reseat the switching cables. That was all part of removing it from the rack.

The power seemed stable, but who knows Although that is not high on my suspect list I cannot rule it out.

I will try swapping the positions of the power amp tubes as well. Could be an issue.

I hate these weird one time glitches, if they cannot be reproduced it is hard to pin down anything, that was the reason for the initial post.

Any thoughts on preamp tubes causing this. I think I have at least one going bad. I am going to buy some today.

 

[tim6string]

Final update, played Friday night with no issues at all. I put a new SPAX7 in the number one spot, squeal went away as expected and the amp worked flawlessly all night. So I am left with either thinking it was the switch which I actually cleaned, heat, which I am not really sure there was more heat than usual, or power related to setup of the rig (because obviously that changed)

Thanks for the input and advice.