Mark IV Malfunctioning

[NickSleeper]

Hello everyone...
I have a little predicament on my hands -

I recently bought a Mesa Mark IV "A" second hand.
This was my first mesa purchase...and needless to say, when I opened it up and plugged it in (don't worry - I didn't just plug in....I used a couple of mesa's recommended preset tone setting combinations) I was quite astounded to hear how cheesy and dry it sounded. I was also surprised to hear sudden "volume swells" and gain boosting in and then dropping out. The tone was absolutely not what I was expecting. At first I figured the tubes were malfunctioning - so I replaced them. After a fresh set, the tone is still not what I had perceived a Mesa amplifier to have, and the volume and gain swells were still occurring. Attached to this post is two links to audio clips I recorded....

The first one has a clip of the "Crunch" channel (Rhy2) with full gain. After the playing ends, I switch to the Lead channel and silence the guitar - This is when you can hear a sort of "chugging" in the background. I continue to play on the lead channel which seems to have a little bit more gain to it, but you will probably agree with me doesn't have the best lead tone on earth.(Understatement)

In the second clip, I AM NOT TOUCHING ANY KNOBS ON THE AMP, GUITAR, OR COMPUTER SOFTWARE - and yet you can clearly hear the gain on the amp fluctuating up and down while I make a consistent signal on the guitar.



mesaiv.mp3
mesaiv2.mp3


If anyone has any idea whats going on, or if im all wrong, the clips sound fine, and that this amp is not for me....Please let me know! Shoot me a message or post here or email me at [email protected] , or AIM SN NickSleeper.

 

[Shep]

take it to a tech!

 

[ibanez4life SZ!]

More than likely requires a preamp tube swap...a full retube would do you well though.

 

[disassembled]

Turn all of the knobs a few times to try and clean out any dirt/grime that may be built up.

Plug a cable in each effects loop jack (send to return)

Pull the preamp tubes one at a time and swap them out one at a time. Just because tubes are new doesn't mean they are free from defects.

Also, check your instrument cable, guitar, and remove any pedals from the signal chain. Do you have an active guitar? Have you checked the battery?

Did you buy the amp locally or from ebay or something? If you can ask the original owner if they know of the problem.



Greg

 

[NickSleeper]

Off to the tech it goes! Ill let you guys know the outcome - and for anyone else who has/will have this problem.

Nick

 

[Xqzdust]

I had a similar problem with my MKIV a when I bought it. It sounded like it had a tremelo effect. I lived in an eighty year old house at the time and the wiring was not up to date. Turns out the ceiling fan was causing the tremelo. Yes proper grounding is important. So think about what is going on in your environment. What other electrical devices could be interfering with your signal.Try plugging it in in another room or even someone elses house. I know this sounds simple but sometimes the simple stuff will drive you crazy

 

[NickSleeper]

Good Call!

Tech just called today and said that it was due to bad wiring(and some grime on the dark sides of the pots) that was messing with the gain, volume, and tone.

Ive learned my lesson - if somethings busted and you dont know what it is, take it to a professional and pay them to do it right.

Hell, it only cost me 40 bucks.

 

[metalblitz84]

That's cool. So often I hear people just give up and sell it or dump it off somewhere. I'm glad you took it to get looked at. Enjoy!!!

 

[NickSleeper]

Just got it back - the noise and the volume / gain fluctuations are gone - but I STILL cant help feeling like my previous amp (Peavey Triple XXX) has more crunch and balls on its rhythm channel than the MKIV. Ive tried various settings - do Mark IV RHY2 channels usually need a boost or distortion? Do I just need to get used to it?

Im still not ready to accept defeat!

 

[disassembled]

I've owned a Triple XXX before I moved to a Peavey Tubefex and then FINALLY went to a Triaxis after listening to people ***** about a preamp is not worth more than few hundred $ let alone over $1k :shock: BALONEY!(cheap bastards!) Now I have a Triaxis, Mark IVB, RK I, Subway Rocket, and too much other crap to list. When I listened to the Triple XXX all I heard was grainy distortion that just seemed too stiff. Yeah, it got heavy and bassy but I had to do some serious tube swapping to get a good tone. The Mark IV breathes more and is soooo much smoother. Any lead amp that I choose from now on must have a smooth quality because that is the tone I imagine for an amp that sits in the mix well. You made the right choice; trust me.

I guess it was good I owned the TA before I got a Mark IV so I had a very good idea of what to expect and how to get what I want.

You should also consider this:

How old are your tubes?
What speaker(s) and cab(s) are you running through?


The thiele 112 cabs are great and having one of them is just the right size for toting around and can be loud enough for gigs. They aren't too expensive on the used market either (between $2-$300).


As far as R2 goes.....it's a tricky channel to dial in but I've read some people choose to EQ R2 first and then go back and EQ R1 since R2 is a little harder to dial in. You really have to pay attention to flub on R2 because what sounds good with R1 may not work AT ALL with R2. I used to like my bass on 5-6 for R1 to get a nice fat tone but it just automatically turned R2 to flub and I really didn't understand. The louder you play the better R2 seems to sound and the more you can really hear your EQ changes.


An OD pedal is a good investment since you can go as cheap as the Digitech Bad Monkey ($40) or as high as your wallet can take you.

Personally, I haven't spent much time with an OD through the Mark IV as I get the tones I want without a boost but I am certainly not opposed to the idea.

The site has a great database of settings which shouldn't be over looked.

Have fun tweaking!


Greg

 

[lockbody]

Ive tried various settings - do Mark IV RHY2 channels usually need a boost or distortion? Do I just need to get used to it?

Yes and yes. A lot of people end up being disapointed in rhy2 because they expect a "modern" crunch channel instead of the late eighties kind that rhy2 really is. For me, rhy2 really shines best for classic rock type music.

I always used rhy2 as more of a "pushed clean" and used an overdrive to kick it to the next level.

 

[NickSleeper]

The Tubes are brand new - JJs - two 6l6 and two el34s.

Cabinet is an Avatar 4x12 with Celestion Vintage 30's.

I love the gain on the Lead channel, I just dont like the idea of using one channel for rhythm crunch and for the leads. Guess I will have to play around with the EQ toggling and knob settings so I can differentiate the two on stage.

Nick

 

[scottywompas]

I use my MKIV with a classic rock cover band and spend most of my time in R2.

I too was innitially not thrilled with R2 but i played around and got pretty close to what I needed for the job.

Gain pulled around 7 bass,mid around 4-5 treble, 8 or so, presense around 5.

It works pretty good for BTO,Rick Drringer,AC/DC,ZZ top,etc..type stuff that we play.

Scott

 

[devilrob1979]

Rhy2 is becoming my favorite channel. It's not super high gain but that's what the lead channel's for. For mid breakup tones RHY2 kicks ***.