Issue with Mesa 50 Cal + tone knobs at different volume/gain/channel settings

[Snoogles]

so I have a Mesa 50 Caliber +
I can only use it at "television/living-room/thin-walled-apartment/cranky-neighbor-next-door" volume levels

I've found that the tone knobs on this amp are very peculiar
they go from left to right: Treble - Bass - Middle

and some how the Bass and Middle knobs are dependent on where the Treble knob is set. if the treble control is lower, then the bass and middle controls have more affect. if the treble knob is set higher, then the bass and mid controls don't affect the tone at all.

and some how the Bass and Middle knobs are interactive in a similar way that I haven't quite figured out.

this phenomenon is SERIOUSLY SERIOUSLY confusing to a tube amp noob

the MIDDLE tone knob is giving me the most problems though, and here are the symptoms:

in the clean channel with the "Gain" knob on a higher setting, and the "Master" volume set to lower settings to compensate for volume loudness, the "middle" tone knob (with the treble, and bass knobs set to lower settings so the damn thing actually has an effect) works as it should up until the 6/10 mark. then turning the "middle" knob higher than 6/10 the sound from the speaker starts to fizzle, crackle, fart, sputter, spit and piss. sort of like there's dirt in the contacts inside the pot. but that's NOT what this is

this issue doesn't seem to repeat itself in the lead channel. maybe because the higher gain masks this phenomenon... edit: scratch that. it does indeed repeat itself in the Lead channel

I might try to make a video of it in the morning.

edit: also, this amp has a "reverb" knob. but that thing doesn't do jack squat. even on the clean channel. knob set on 10/10 its dry as the Gobi dessert in summer

 

[Boogie Bill]

Re: Issue with Mesa 50 Cal + tone knobs at different volume/gain/channel settings

Too bad you can't let your .50+ rip. These really aren't bedroom amps, they work best on a stage or in a studio.

The first thing you need to do is to thoroughly familiarize yourself with the controls. Read the owners manual, you can download a copy from the Mesa website. There are sample settings, and a description of how each of the controls work. You're right, the controls are VERY interactive; it allows for tremendous tonal variation. You don't get that with a lot of other companies' amps. But the controls do have limits, so you'll want to try to keep them set close to the sweet spots.

I'd only be speculating on the noise coming from the Mid pot. It could be a bad pot, or a bad ground, or a circuit problem. You should give Mesa a call, and see if they can point you in the right direction.

Likewise, it's hard to pin down the reverb issue from a distance. These amps don't have the deep reverb of a BF Fender, though. You could try replacing the reverb driver tube. (The manual probably has a tube function chart.) Check that the gray and white reverb tank wires are connected at the pan, and the RCA plugs are in their correct jacks. See if a footswitch makes a difference.

It shouldn't be a surprise that a 25-year old amp might need a tune-up and a bit of TLC. Once you have a better idea how to use the controls, you should be able to produce some great tones from this amp.

Bill

 

[JeffB]

Re: Issue with Mesa 50 Cal + tone knobs at different volume/gain/channel settings

Heh.

Welcome to MESA products.

My first was a studio 22, then a 50 cal.

Both were a complete PITA,and I did not keep them long because I was always having to vary output volumes for different places, and my settings were constantly screwed. The 50 def needs to be pushing some air to sound worth a crap.

Sounds like you need to take the amp in for the reverb issue.

In general, I find that MESAs tones.shpuld be set by the idea that MORE= subtraction. E.g. need more mids? Reduce treble and bass slightly. Want less bass? Add more mids and treble.

Def not easy to dial in good tones.

 

[Dr. Vegetable]

Re: Issue with Mesa 50 Cal + tone knobs at different volume/gain/channel settings

I'm relatively new to Mesa myself, but my take on it is that playing a Mesa is like driving a car with a manual transmission. You have a little more control over your tone, but you need to take more time learning how to operate it.

The tone controls do interact with one another, and Mesa talks about this at length in their owner's manuals. They also talk a lot about a different approach to using the controls, and usually have some good sample settings that you can use as a starting point.

No reverb, and crackling/scratching sounds could be one or more blown tubes, dirty pots and jacks, loose connections, or any of a number of other ailments. Start by getting that bad boy tuned up so you know you have a stable platform.

Good luck with it!

 

[jpistolas]

Re: Issue with Mesa 50 Cal + tone knobs at different volume/gain/channel settings

As far as your technical issues you should visit the grailtone message board. There's several folks that can help quite a bit with your 50 cal. My DC-5 (similar amp) has a very weak reverb issue. Just been too lazy to address it. I can hear it though.

My solution for tolerable bedroom/apt volumes has been to make a home made master volume. When your neighbors are away, get your volume and settings the way you want and place the volume control in the effects loop. Behaves like a master volume. I built mine after this design:

Many thanks fo Beavis Audio. Guy is a genius and explains things well.

The switch is unnecessary. Handy if you want to use it as a boost for solos or something though.

Also, you don't need an actual pedal enclosure. Mine's in a small cookie tin. :14:

 

[Chickenwings]

Re: Issue with Mesa 50 Cal + tone knobs at different volume/gain/channel settings

if the mids are set at 5, then the bass and treble are also at 5 by default...even if the knobs say zero.
The mid knob is kinda like a secondary gain knob on your amp.
If your mids knob is at 5, and your treble and bass knobs are at 1, then its the same amount of treble and bass as if they were both on 6 and the mids were on zero.
So it works like this....wherever the mids knob is, thats your base level for all 3 bands. As you dial up the other knobs, that letting you know how far above the base level they go.
For a chance to see how this all works in a visual sense, try downloading the duncan's tone stack calculator and fiddle with the knobs on the fender tone stack model:
http://www.duncanamps.com/tsc/

So for a "flat" (there is actually no such thing as flat) frequency response on your amp, set bass and treble to zero and wind up the mids until you are happy. If you want more bass and treble, just dial them in to taste.
Amps also behave differently as you wind up the volume and the extremes of bass and treble become less defined and the mids become more prominent.
You actually have a killer amp...but its definitely not built for bedroom levels. Its a serious professional musician's gigging machine. Its like having a ferrari and using it only to roll up the driveway to pick up your mail from the front gate. Its no surprise that the clutch feels heavy and the wheels spin in the gravel.

Re: your reverb...its busted. Most likely one of the tiny wires inside the tank that connect to the springs have worn out and broken. Its very common and easily fixed.

Re: the crackling sound. I think your amp is most likely due for a service and very likely a new set of tubes. At the very least you need to do some troubleshooting to diagnose if it is only one or more of your tubes that are on the fritz.