Why is the Mesa 2:90 so much more powerful than SS power amps?

GotMetalBoy

GotMetalBoy

Power User
I have a Mesa Boogie Simul Class 2:Ninety that's over 10 years old and it is the loudest yet clearest power amp I have ever used. Why if its only 90 watts per side can it be more powerful than a 1000 watt per side solid state power amp? The only SS power amp I have ever come close to being as powerful was my Carvin F1200 believe or not and the only reason I don't have it anymore is bc it got wet when my basement flooded 4 years ago :-(

I know the 2:90 and F1200 both colored the sound a little but I felt like they did it in a Fetcher Munson kind of way. When I play through my 2:90 I have the deep, half and modern off, keep the presence knobs all the way down and level all the way up and control the level w/ my AF2. I play very dynamically, so I need lots of headroom. I never had a chance to play my AF2 through the F1200 but I had played my Mesa Boogie TriAxis through both amps.

Also, I'm thinking about replacing my 2:90 w/ a Matrix GT-1000. Is the Matrix going to be as powerful as my 2:90? Should I get the single or double rack space? I'm used to the fan noise in my 2:90 and F1200 and it's never bother me but I don't know if either is considered quite. My main reason for replacing my 2:90 is to reduce weight and the yearly cost of tubes.
 
GotMetalBoy said:
I have a Mesa Boogie Simul Class 2:Ninety that's over 10 years old and it is the loudest yet clearest power amp I have ever used. Why if its only 90 watts per side can it be more powerful than a 1000 watt per side solid state power amp? The only SS power amp I have ever come close to being as powerful was my Carvin F1200 believe or not and the only reason I don't have it anymore is bc it got wet when my basement flooded 4 years ago :-(

I know the 2:90 and F1200 both colored the sound a little but I felt like they did it in a Fetcher Munson kind of way. When I play through my 2:90 I have the deep, half and modern off, keep the presence knobs all the way down and level all the way up and control the level w/ my AF2. I play very dynamically, so I need lots of headroom. I never had a chance to play my AF2 through the F1200 but I had played my Mesa Boogie TriAxis through both amps.

Also, I'm thinking about replacing my 2:90 w/ a Matrix GT-1000. Is the Matrix going to be as powerful as my 2:90? Should I get the single or double rack space? I'm used to the fan noise in my 2:90 and F1200 and it's never bother me but I don't know if either is considered quite. My main reason for replacing my 2:90 is to reduce weight and the yearly cost of tubes.
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Hi there,
If you dont mind me asking, what cab/s are you going to be playing into ?
My best regards
Matt
 
GotMetalBoy said:
I have a Mesa Boogie Simul Class 2:Ninety that's over 10 years old and it is the loudest yet clearest power amp I have ever used. Why if its only 90 watts per side can it be more powerful than a 1000 watt per side solid state power amp?
Click to expand...


Short answer: It isnt.

Long answer:

Let us assume you are playing into a 16 ohm cab, and the Mesa has it's transformer set to give 90W into 16 ohms ... you'll get 90W at roughly the point where at starts to compress and maybe 120 or so when its nice and crunchy.

Your 1000W amp .. maybe its 2 ohm rated? .. so it will develop 1000W into 2 ohms ... but only 500W into 4 ohms, 250W into 8 ohms and 125W into 16 Ohms ...

The other thing to bear in mind is that valve amps are often rated to the point where they are clean, but there is a further 3db or so of power to be had as they compress and distort .. so you could expect to get 200W of power out of your 100W rated head once you push it into "crunch" territory ... a solid state amp tend to just hit the end stop and go clipped hard .. so you have to keep a little way off the limits to keep it clean sounding, the 100W rating on a solid stat

However, hook them up to a 4 ohm cab (eg a 2 x 12 with a pair of 8 ohm speakers in parallel) and the situation would be reversed. With the same transformer tap the Mesa would develop just 25 watts or so into 4R, and the solidstate amop 500W. Its just a question of matching the cabinets to the amps to get the best out of them. When run into their designed impedances, they work just as expected.

This is part of the long running misconception that "solid state amps are not as loud" ... mostly down to people running amps designed for 2 ohm or 4ohm into 16 ohm cabs and wondering why they dont develop much power. The only upside is that an amp designed for 4R run into 16R doent mind too much .. but run a 16R amp into 4R and your output transformer may let the smoke out ...
 
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MatrixAmp said:
Hi there,
If you dont mind me asking, what cab/s are you going to be playing into ?
My best regards
Matt
Click to expand...

For guitar I have a Marshall 1960av 4x12 Slant cab, Peavey 412MS 4x12 Slant cab and Peavey 412M 4x12 Straight cab. Each cab is 150 watts RMS at 8 ohms per side when stereo and 300 watts RMS at 16 or 4 ohms when mono.

For bass I have a Peavey 412MS 4x12 Slant cab that I replaced the speakers w/ 4 Carvin PS12-8 300W 12 Inch Speakers, so it can handle 1200 watts RMS at 8 ohms mono. I'm getting a SWR Goliath III 4x10 cab soon and it can handle 700 watts RMS at 8 ohms. I may get 2 of them if I can find used ones in good condition and at the right price.
 
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As crazy says, power is power.

However, several things come into play.

A ss amp had a max op, but to remain clean needs to stay on that power. In practice that means staying 3-6db below its max for the majority of the time. That's 1/4 power so around 250w. A valva amp gives its op clean and I'd quite capable of double that when pushed, so neater 180w.

Next, rated power is into a given load. For the valve amp you chsnd the tsp to always match the loaf but not with a ss amp. There normally rated at 4ohms (though can be 2) and for every doubling of the loaf you get roughly 2/3 the power. Do into a 16 ohm can the ss amp is down to neater 100w.

Finally the op is for a given ip strength, and the amps may differ. The mesa is likely 0db, which is 0.775v. Many ss amps ate +4 db which is 1.4v. That means for the same signal the ss amp gives half its rated power as the ip is half required to generate it.

Add these together and its quod possible your 90w rated MRSA could actually produce 280w, while the 1000w rates ss amp may only be producing 50w.
 
Oh, forgot this. A .1000w rated ss amp is generally two 500w channels not 1000 where as the mesa is two 90 w channels.. So unless you bridge the amp, its giving another 50% less op, so now your comparing a potential 180w. From the mesa to 25w from the ss amp.
 
1. The loudness of a speaker is proportional to the Voltage applied at its terminals. When you see a sensitivity rating that is 2.83V (1W@8Ω) applied το speaker terminals NOT 1 real watt.
2.A SS amp has a voltage that is indepentent of the load( constant voltage). The output voltage can keep going up until it reaches the PSU supply voltage. Then it clips.
3.A Tube amp has a voltage ouput voltage propotrional to the load impedance (constant current). A typical guitar speaker has an impedance that can be as high as 50 Ohms at the resonance frequency (80-100HZ) and as low as 4 ohms around 250HZ.

A SS claiming 100W/8Ω will output 28.28 Volts. A tube amp would produce the same Volts if it was driving a pure 8Ω resistor but at the resonance freq where the impedance is 50 Ohms it will (try to) output 50/8*28.28V= 176Volts or 16dB more than the SS or 3900W !
Of course the tubes will clip way before that . I fact I remember reading in a Marshall JCM800 schematic that that amp's equivelant power would be around 270W using the calculations above and taking into acount the actual el34s current capacity.
 
drosei said:
1. The loudness of a speaker is proportional to the Voltage applied at its terminals. When you see a sensitivity rating that is 2.83V (1W@8Ω) applied το speaker terminals NOT 1 real watt.
2.A SS amp has a voltage that is indepentent of the load( constant voltage). The output voltage can keep going up until it reaches the PSU supply voltage. Then it clips.
3.A Tube amp has a voltage ouput voltage propotrional to the load impedance (constant current). A typical guitar speaker has an impedance that can be as high as 50 Ohms at the resonance frequency (80-100HZ) and as low as 4 ohms around 250HZ.

A SS claiming 100W/8Ω will output 28.28 Volts. A tube amp would produce the same Volts if it was driving a pure 8Ω resistor but at the resonance freq where the impedance is 50 Ohms it will (try to) output 50/8*28.28V= 176Volts or 16dB more than the SS or 3900W !
Of course the tubes will clip way before that . I fact I remember reading in a Marshall JCM800 schematic that that amp's equivelant power would be around 270W using the calculations above and taking into acount the actual el34s current capacity.
Click to expand...

And that is only accounting for the amplifier/speaker relationship, which is further complicated by a crossover in the case of a monitor which incorporates a passive crossover...
 
A tube amp into an frfr would be a disaster because u are dealing only with a 12" resonance but also crossover resonance and HF resonance. If you look at the impedance of a 2 way speaker THATS your eq profile
 
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