Re: Hot plate vs. Mass (I have searched)
I'll chime in...
I own the Mass 150 and a Hot Plate. Both are effective tools, but different.
The Hot Plate is THE industry standard. I mean it! Amp companies will sometimes NOT honor warranties if its anything but a Hot Plate (this is not ALWAYS the case, but it does hold). I can also attest they are built like tanks.
The Hot Plate is more aggressive and has more attitude, allowing the amp to really sing. This is NOT always a good thing. Why? Because I have played many a club where you need to achieve your sound at a VERY controlled volume so they can mic you, and the sound man will be quite particular. You need to respect that! So it's better for those who want MORE volume. This can be trouble with a NMV Marshall as your AMP volume settings really impact tone, breakup, and feel.
I have called THD and they feel the 4dB increments on the Hot Plate are ideal to human hearing. Moreover, they feel the best way to balance out the sound is to change the amps volume, which is NOT the solution I want with a lot of amps, esp NMV's. BTW, the noise redux is a nice little feature, bc the amp still seems to shine thru (not totally, but close).
Onto the Mass. The Mass, as some people say, almost feels like it is never gets as loud as the Hot Plate, or as loud as the amp should be when the MASS is on 10. People who want volume take note!
The people who like the Mass often remark that it has a nicer feel. I liken this to the greasy and spongy feel of a cranked NMV, OR you can take the comparison of an Alnico 2 magnet and its spongy feel (Mass) vs the Alnico 5 open, brightness.
The Weber Mass' main appeal is the CONTINUOUS VOLUME CONTROL. Given that it really dials in that old school tone, adding the continuous control means you can dial in your exact tone and then use the Mass almost like a Master Volume control.
The Weber works on the principle of a speaker motor taking up the load - so it does feel and sound different but its not a mile of difference. Its like a variation on a sauce - like Heinz vs Hunts Ketchup, or maybe not even that much.
Both units have tonal coloration, and get to sound more like poop as you lower the volume - you can only know by playing them.
The Mass lacks a fan, and at times it feels warm under heavy use. It is a little bigger and bulkier. The knobs are a little harder to turn.
Thus far I own BOTH and have yet to be able to decide which to sell. I would say the Hot Plate is the industry standard and opens up the amp more for live playing BUT, if you have volume considerations like at home or you play places like high end clubs or casinos you might want to look at the Mass.
I will probably make a new YouTube and start doing some gear demos as they have helped me when i have seen other's demos in the past. I have video of me with everything from Lindy Fralin amps to G12-65s to Menatone pedals, but they are for my own reference/use, since I look like hell and am playing sloppy hehehehehe.