Messa Express 5/50watt modification?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by donnyb, Jan 26, 2012.

  1. donnyb

    donnyb Member

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    Hi again. If you read an earlier thread of mine where I was chasing getting the sounds I need from my MB Express 5/50.... I got great advice and use the amp now in the 5 watt mode. It sounds great in the distortion channel !

    However, I have noticed over the last month at gigs that it does not sound as sweet in the Clean Channel in 5 watt mode, less depth not as clean. It's OK, but I miss how it sounds in the 50W mode, even though I did not (due to our venues) play with much volume.

    So, I asked Mesa Boogie USA if I could modify this amp to make the 5/50W switching done by a footswitch while gigging. I explained to them that when in distortion mode doing solos for example, I would be on 5 watts in Channel 2, and then switching back to Channel 1, and also switching to 50watts mode as I finish up the solo. I appreciate the volume levels would need to be set up right between the Channels and it would be 2 foot actions - one to change the Channel, one to change the wattage mode. I asked MB if it would : 1. Damage the amp internals going from one power setting to another all the time,, and 2. would the change be seamless?

    Their response was quote "We do not have any information regarding a mod like this. It has never been performed here by us, & therefore we really can not offer any advice on such a thing.
    Sorry for the inconvenience.
    Thanks for your interest in MESA! " UNQUOTE

    Would anyone like to give their opinions on this mod as Im sure I would not be the first to raise this. Thanks, Don
     
  2. phsyconoodler

    phsyconoodler Member

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    It really is not a good idea to do a mod like that.Not only is is almost impossible because of the PC board layout in that amp,it's really not a good mod.
    Because of the nature of such a mod and the way the amp derives it's 5/50 watt modes,it would likely cause damage to the amp because of the voltage changes involved.
     
  3. donnyb

    donnyb Member

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    Im not sure I follow physconoodler (that's hard to type! :) ). What I want to achieve at a gig is theoretically possible now by reaching over and flicking the amp 5/50 mode switch. Are you saying that by making it more convenient to do so via a footswitch implant, my more frequent action of swapping between wattage modes will do the damage? Or put another way, did Mesa only ever anticipate that users would only change between wattage modes infrequently = no damage?
     
  4. AR-305

    AR-305 Member

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    The mesa boogie mark v has a power selector switch on each of it's 3 channels. The roadking and roadster also have assignable channel specific power switches. This is accomplished by a somewhat complex "switching matrix" with multitudes of relays, logic chips and muting transistors. The mod "could be done" but it would first void any remaining warranty from mesa and you would have to wrestle with the question "am I willing to pay a tech qualified to design and install the circuitry necessary"? OR wouldn't it be easier and more cost effective to use an A/B switch and two different amps.
     
  5. phsyconoodler

    phsyconoodler Member

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    I wouldn't want to do it after working on a few mesa amps.There is very little room inside those amps to add stuff like extra relays.
    It just seems like you could accomplish the same thing by switching in a boost pedal in the 5 watt mode.
    Modding mesa amps is somewhat of a nightmare even on earlier versions that didn't use jfets and multiple relays.
    You could theoretically use a relay to switch the modes but a switch is designed to handle high voltage and current and a relay is best left to signal paths unless it's a heavy duty automotive style one and then power supply becomes an issue.
    I suggest you try more setting adjustments and not dwell on the topic too long.Enjoy your amp before it gets turned into a molten mess with mods that often go wrong in complicated amps like the mesa.
     
  6. AR-305

    AR-305 Member

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    I UNDO way more botched attempts at "mods" on mesa amps than install them. And I won't begin any rants. Like was just said, there are many good alternatives to try first.
     
  7. donnyb

    donnyb Member

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    Thanks to All. I get the message... Is it worth it ? NO.

    So I will keep hunting for a tone in 5 watt mode for the Clean channel that comes closer to the depth of tone it (the clean channel) has in the 50 watt mode. Fortunately, the Mesa Express has a lot of tone control as I have found courtesy Gear Page members who have taken the time to respond to threads I have posted. Many of us think we know stuff, and we do, but we also don't know what we don't know, so Im never too old to ask and learn ! thanks again.
     
  8. soundchaser59

    soundchaser59 Supporting Member

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    There is a good reason why those power select switches are NOT on the footswitch, they are toggles on the back of the amp, inconvenient to get to......for a reason. The most obvious clue is you are supposed to switch to Standby mode before you change the power select. That loud pop you hear when you change it without going to standby is your clue that this is not good for the amp.

    In my experience with the Express amp, the best answer for what you want is a clean boost in the fx loop. You'll get an instant warm and clean power/volume boost without any of the preamp gain/distortion you would get if you put the boost in front. In fact, the clean boost in the fx loop makes the Express sound so rich and warm I ended up leaving my clean boost on all the time. For me it made the Clean channel what a clean channel is supposed to be, clean and loud.
     
  9. donnyb

    donnyb Member

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    Thanks Soundchaser. I have a Xotic BB Plus, which I could use as a volume boost and tone control (instead of setting it up for overdrive/distortion). Is that what you are suggesting via the effects loop?
     
  10. donnyb

    donnyb Member

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    Just to clarify - Its not a volume issue my wanting to use the 50 watt setting in the clean channel - its the tone difference I hear between the 5 and 50 watt modes in clean.
     
  11. soundchaser59

    soundchaser59 Supporting Member

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    Yes, in fact the Xotic BB is one of the pedals I used for my fx loop boost at first. But later I switched to the Boosta Grande, then to a Visual Sound Truetone. Even if you dont make it louder, it will definitely change the tone. I tried it at first because I was wanting that rich, full tone at low volumes, and it seemed to do that for me.
     
  12. hmontgomery

    hmontgomery Member

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    Sell it and get a Lonestar (Classic or Special). They have channel assignable power switches.
     
  13. donnyb

    donnyb Member

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    (Groan) Pity it was offered on the Express. Maybe MB will read this and add it to the Express in the future. Its the only thing I would like to be able to do. I will try the Lonestar thank you. The Aussie to US $ is pretty good, so maybe I wont go backwards too much .
     
  14. soundchaser59

    soundchaser59 Supporting Member

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    I was never able to bond with the 5 watt mode. When I went back and forth the full power mode definitely swamped the 5 watt sound.

    I'd much rather have the ability to footswitch all four channels at will, if I could only pick one thing to change on the Express.
     

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