Problem with a NEW MARK IV!!!!

[rich]

Hi, I'm new to the board. I finally got my Mark IV after waiting more than two months for it to be built. Its great and I'm experimenting with it, but I have a problem.

I used it at band practice for the first time at louder volumes. My lead channel volume was 3 and my output was 2. All knobs were pushed in except the gain knob. The gain was around 7.5(pulled out), the treble around 7.5, the lead drive about 7.5 and the presence around 2-3. Whenever I stopped playing, even while muting the strings, a loud squeal was heard (no matter where I was facing). There was no humming or anything like that, just a really loud, ear-piercing feedback/squeal sound. For clarification, I did not have the bright pulled, and I did not have the voicing to mid gain. Thanks for any help

I have owned a dual rec and have never had this problem not matter how high my distortion was (although I rarely put it above 1:00). I have never owned a noise gate, and I would rather not buy one. I don't even know if that would stop this squealing. Without the pull fat, it seems like I wouldn't be able to have enough saturation
Thanks

 

[rich]

i'm also running the eq in a classic v, full power, pentode, bass knob on 2 and mid knob on 3

 

[Platypus]

Sounds like a microphonic preamp tube to me... probably happened during shipping. Replace them one by one until the problem goes away.

 

[rich]

hmm sounds very possible...maybe thats why there is an extra pre-amp tube taped to the back of my amp from the factory hah

 

[Platypus]

hmm sounds very possible...maybe thats why there is an extra pre-amp tube taped to the back of my amp from the factory hah

haha, they always ship an extra

Give it a shot.. if you need help diagnosing the problem tube check out the FAQ in my sig.

 

[rich]

thanks for the quick replies dude...I can't wait to get home to try it...

I am loving this amp so far by the way...I had the eq in a classic v, but I recently messed with it and got it sounding close to a mark IIc+ (or rather, shockingly close to the master of puppets tone)

the sliders on the eq were about half way up, 3/4 up, 1/4 up, 3/4 up, and a little more than half way again....with my emg 18 volt mod, its pretty awesome

 

[Restless Rocks]

EMG 18volt Mod? Does the squealing noise stop when you turn your guitars volume off? Have you tried a guitar with passive pickups to determine if the problem is from the amp or maybe from the guitar? Let us know what you find out.

 

[rich]

yea, the squealing stops when i turn my volume off. No, al my guitars have emgs, almost all with the 18 volt mod. if its from the guitar, are you saying that my pickups would be the problem? if so, why would it happen on the mark iv, but not my dual rec? thanks dude

 

[bryan_kilco]

yeah sounds like a tube related problem to me, happened to my amp when the tubes were going bad.

 

[psychodave]

hmm sounds very possible...maybe thats why there is an extra pre-amp tube taped to the back of my amp from the factory hah

haha, they always ship an extra

Give it a shot.. if you need help diagnosing the problem tube check out the FAQ in my sig.

3 preamp tubes were bad on my new Mark IV. I am still waiting for my replacement Mark IV. :x

 

[rich]

your getting a new mark iv because of tubes? can't mesa just send you replacement tubes under warranty?

 

[psychodave]

your getting a new mark iv because of tubes? can't mesa just send you replacement tubes under warranty?

Not because of tubes….although they were bad. My Mark IV was messed up and have a cracking noise in it on every channel….with any tube. My local Boogie dealer didn’t want to mess with it. Since I already have a Mark IV and know how they sound, I was able to send it back to the dealer and get a new one.

 

[jerseydrew]

your getting a new mark iv because of tubes? can't mesa just send you replacement tubes under warranty?

Not because of tubes….although they were bad. My Mark IV was messed up and have a cracking noise in it on every channel….with any tube. My local Boogie dealer didn’t want to mess with it. Since I already have a Mark IV and know how they sound, I was able to send it back to the dealer and get a new one.

Now that's service!

 

[psychodave]

your getting a new mark iv because of tubes? can't mesa just send you replacement tubes under warranty?

Not because of tubes….although they were bad. My Mark IV was messed up and have a cracking noise in it on every channel….with any tube. My local Boogie dealer didn’t want to mess with it. Since I already have a Mark IV and know how they sound, I was able to send it back to the dealer and get a new one.

Now that's service!

On the dealers part. The guy at Boogie was a jerk....and didnt seem to understand the Mark IV, yet he is the "manager". :roll: