Mesa Mark IV Noise

[nicyrocks]

I have a fairly new Mesa Mark IV Widebody Head (about 6-mo. old) that I've just noticed is doing something that isn't right. It sounds like the reverb unit (but not sure). When I play a chord in any of the three distortion channels (R2, Lead or Lead EQ), there seems to be some bleed over reverb sounding almost like springy sounding noise. It doesn't seem to affect the tones or sound quality; only the after-math of the chord after the strings are muted. Any idea's?

Thanks for your help and support. Tom

[bbartilson]

I have a fairly new Mesa Mark IV Widebody Head (about 6-mo. old) that I've just noticed is doing something that isn't right. It sounds like the reverb unit (but not sure). When I play a chord in any of the three distortion channels (R2, Lead or Lead EQ), there seems to be some bleed over reverb sounding almost like springy sounding noise. It doesn't seem to affect the tones or sound quality; only the after-math of the chord after the strings are muted. Any idea's?

Thanks for your help and support. Tom

If I'm interpreting what you're describing correctly, this was a well known issue on the MKIII's of which I saw quite a few for service. It's been so long since I had one with the symptom that I don't even recall what the problem actually was. The fix was to change one resistor value - something about the reverb drive for the clean channel sneaking into the return for the hot channel(s). I can almost recall the values - like a 150k becomes a 220k. Unfortunately, I have no recollection of why or where, and those notes are long gone. Well, wait. Enzo might still have them. He keeps everything.

Not all of them did it, but the ones that did were easy to fix. In any case, one phone call to Mesa should confirm or deny that this is the same issue. I suspect that it is. It just sounds too familiar.

-Bill

[pdf64]

What guitar are you using?

[stokes]

If you dont get an answer here,try this link to the Boogie Board,http://forum.grailtone.com/index.php Lot of guys over there that are pretty current on Mesa problems. I've never heard of it in the MKIV,I thought it was the MKII,and thought Mesa had resolved it starting with the IIC.Not sure if this was the actual problem either.What you describe sounds like it could possibly be a microphonic reverb tube.Does it do it with the reverb switched off?Has it always done it,or did it start recently?

[Don Moose]

The MkIV schematic I have has a reverb knob (just one), but no switches to turn it on or off.

[nicyrocks]

Thanks for the feedback

Thanks for all the feedback and great suggestions. I think I might have it figured out, however I am still at a loss on what to do. I think I may make a trip to the music store tomorrow. I am using a PRS Custom 24. The problem only occurs when using this guitar. My Strats sound great no resonance noise. I tried the PRS in my DC3 and same issue. I am thinking it is the guitar. Any thoughts - ????

Thanks again,

Tom

[Don Moose]

Your PRS has a whammy bar?
Then so does your strat.

Just for fun, stuff a sock or something in the whammy's spring cavity to keep it from reverberating.

[stokes]

The MkIV schematic I have has a reverb knob (just one), but no switches to turn it on or off.

The MKIVB,which I assume this is,since he said it is fairly new,has a foot switch for the reverb.
Thats an oddity,that it only happens with the PRS.The only difference that comes to mind offhand is that the humbuckers put out a bigger signal than the single coils in the Strat.Try tapping v3 and v4,with the controls set like you have them when you are playing and see if tapping either of them causes the sound you are hearing.

[nicyrocks]

Thanks - I'll try this. The Strat also has a whammy bar, but no noise.

[nicyrocks]

The MIV doesn't have a footswitch for the Reverb. I tried shutting it to zero and even unpluged the unit.... still the same noise. Thanks for the feedback!

[Jag]

I have a CE24 with wammy that does this too. My strats don't have that issue. Trying the sock thing will show if it's the guitar as opposed to the amp.

[Don Moose]

If that works, you gotta wonder how to actually fix this.

Replace the springs with surgical tubing?
Weave some rubber-band-things around the springs in a couple of places? (big, fat ones that won't slip in between the coils - like surgical tubing)

Try fewer springs at higher tension?

Do you actually USE the whammy? If not, block it and yank the dang springs out alltogether.

[Jag]

I think you kind of have to live with it. I've played around with different numbers of springs and differing tension but you still get the bleed through.

I don't use the trem so I made a little spacer of hardwood to put under the bridge and "blocked" it. Because of the way the PRS is built, you can't block it the way you would block a Strat, you neet to make a 1/8" hardwood spacer to fit unter the bridge and tighten down the springs. Then I put a piece of foam under the springs to dampen the ring. I'm more into altered tunings than whammy dives so, it works for me. Now that I've got a couple of Pauls, I'll probably set the PRS up for trem again though.

I suspect well potted, lower output pickups (not as in active though) might help too, but then you're messing with the tone. IIRC there used to be a company in the '80's that sold "quiet springs" that were coated with PVC. Not really sure how well that would work.

[stokes]

The MIV doesn't have a footswitch for the Reverb. I tried shutting it to zero and even unpluged the unit.... still the same noise. Thanks for the feedback!

The MKIVB does have a footswitch,if it is only 6 mos old,as you say,it is a IVB and the jack for the footswitch is on the bottom of the chassis inside between the tube sockets.If you dont have a footswitch,which you obviously dont,you can turn it off by inserting a "shorted jack" in the recepticle.