Long time follower and now first time poster on Talkbass! I hope everyone has enjoyed their holidays! From the looks of it, seems most of us have acquired some new gear, including myself. Now having both the old MB Fusion 500 and the Legacy 500, I thought I could share some of my observations.
MB Fusion 500:
Although subjective, this is an absolutely incredible sounding amp. I would describe this tone as clean, articulate, warm, powerful, and easily cuts through the mix. With dedicated A and B channels, you can go from clean to burly in no time. Combined with Master - A and -B, its nice to have the option to either maintain the same volume or increase the B-Channel for solos if or whatever application you need really. Personally, I have rarely used this feature simply because I'm a simpleton with no need to switch channels. Nice to have though. One thing I do like about this head is the adjustable contour knob. I like this because its not a simple on or off feature and I can carve out the mids however I like. Other features I enjoy is the selectable mid frequency switch for tone sculpting, "presence" switch for a brighter top end, and the "deep" switch for a pretty noticeable bass boost. DI out is incredibly silent. No issues with mine whatsoever when running into a Focusrite. However, as small as it may seem, my only real problem with this amp is the cooling fan. As others have noted, it sounds like a small jet on takeoff. If you're recording DI, its not an issue. If you're using a mic', I'd recommend getting it as far away from the amp as possible. At the end of the day, you really can't go wrong with one of these.
Legacy 500:
Also a matter of taste, this too is a fantastic sounding amp. Personally, I have never tried the older RB series so I can't speak to its similarities but if I understand it correctly, I would agree that this head is definitely capable of achieving that "grind" that GK is known for. Like the Fusion however, the Legacy exhibits similarities as in its all part of the GK "sound" except with a few added bonuses such as the overdrive channel (which essentially is an A/B channel), build quality, and improved electronic components for longevity. As far as tone is concerned, everything about the Fusion that has already been said also applies to this head except a few key differences. The biggest differences being 1) the low end -- bass for days and a lot tighter without burying the bass in the mix.. 2) low mid "grind" -- having done an A and B test of this, I can say with certainty this amp easily cuts the mix from this low end growl.. 3) although its not adjustable, I think GK got it right with the contour settings. Even though its either on or off, whatever frequencies this switch affects are the right ones. To my ears, this cuts out the mud and really cleans things up.. Really, the only thing I don't like about this amp is once its turned off but in standby mode, there seems to be a dull ticking noise that (realistically) can only be heard if you put your ear right to it. Perhaps mine is faulty but I wouldn't expect this to be an issue for others. May be a capacitor or something.. Either way, it does not affect tone. I may just have to contact support at some point.
Conclusion:
Both are absolutely fantastic heads and you really can't go wrong with either. Tone wise, if you're looking for something a tad bit mellower, I'd go with the Fusion. If you want the additional low end grind, go for the Legacy. As a player who only plays at home in "studio," power requirements aren't factored into this thread but it should be noted that if you play bigger venues, go for either the Legacy 800 or Fusion 500.. or if you're playing stadiums, go for the Legacy 1200 or Fusion 800.
MB Fusion 500:
Although subjective, this is an absolutely incredible sounding amp. I would describe this tone as clean, articulate, warm, powerful, and easily cuts through the mix. With dedicated A and B channels, you can go from clean to burly in no time. Combined with Master - A and -B, its nice to have the option to either maintain the same volume or increase the B-Channel for solos if or whatever application you need really. Personally, I have rarely used this feature simply because I'm a simpleton with no need to switch channels. Nice to have though. One thing I do like about this head is the adjustable contour knob. I like this because its not a simple on or off feature and I can carve out the mids however I like. Other features I enjoy is the selectable mid frequency switch for tone sculpting, "presence" switch for a brighter top end, and the "deep" switch for a pretty noticeable bass boost. DI out is incredibly silent. No issues with mine whatsoever when running into a Focusrite. However, as small as it may seem, my only real problem with this amp is the cooling fan. As others have noted, it sounds like a small jet on takeoff. If you're recording DI, its not an issue. If you're using a mic', I'd recommend getting it as far away from the amp as possible. At the end of the day, you really can't go wrong with one of these.
Legacy 500:
Also a matter of taste, this too is a fantastic sounding amp. Personally, I have never tried the older RB series so I can't speak to its similarities but if I understand it correctly, I would agree that this head is definitely capable of achieving that "grind" that GK is known for. Like the Fusion however, the Legacy exhibits similarities as in its all part of the GK "sound" except with a few added bonuses such as the overdrive channel (which essentially is an A/B channel), build quality, and improved electronic components for longevity. As far as tone is concerned, everything about the Fusion that has already been said also applies to this head except a few key differences. The biggest differences being 1) the low end -- bass for days and a lot tighter without burying the bass in the mix.. 2) low mid "grind" -- having done an A and B test of this, I can say with certainty this amp easily cuts the mix from this low end growl.. 3) although its not adjustable, I think GK got it right with the contour settings. Even though its either on or off, whatever frequencies this switch affects are the right ones. To my ears, this cuts out the mud and really cleans things up.. Really, the only thing I don't like about this amp is once its turned off but in standby mode, there seems to be a dull ticking noise that (realistically) can only be heard if you put your ear right to it. Perhaps mine is faulty but I wouldn't expect this to be an issue for others. May be a capacitor or something.. Either way, it does not affect tone. I may just have to contact support at some point.
Conclusion:
Both are absolutely fantastic heads and you really can't go wrong with either. Tone wise, if you're looking for something a tad bit mellower, I'd go with the Fusion. If you want the additional low end grind, go for the Legacy. As a player who only plays at home in "studio," power requirements aren't factored into this thread but it should be noted that if you play bigger venues, go for either the Legacy 800 or Fusion 500.. or if you're playing stadiums, go for the Legacy 1200 or Fusion 800.