Solid State Amp Watts VS Tube Amp Watts

[coyote]

You're kind of begging the question; of course that stuff matters when choosing what you're going to use, because it affects the subjective experience of the sound.

Yes. And no.
If I play thru an amp/speaker rig that sounds good to my ears, then if I want that sound again from a different rig it helps to know the specs of the earlier rig. But if I enter a stage and play thru an existing rig and it's awesome, or if I walk into a music store and plug into a random amp and it sounds great, then the sound is all that matters! Particularly nowadays, when almost every stage deploys sound reinforcement (which obviates the need for a big guitar rig), all that matters is the sound experience itself.

But let's turn your argument around. What if my default guitar 'requirements' were three single-coil pickups, a 25.5" scale, and an alder body? And if a guitar lacked those specs I refuse to try it? Answer is that I would never have even tried a PRS! But I saw that 408 hanging there, and even though I'm a "Strat player" I sidestepped my tech specs and picked it up.

That is why specs don't matter. All that matters is the subjective experience of the sound (for amps), and of playing (for guitars).
JMO of course.

 

[Boogie]

Like the old days of specmanship of consumer-grade stereo amplifiers, it's tough to make an apples-to-apples comparison to amplifiers - and preamps - when the methods of stating specs are, well, speculative. Finding a common denominator to make real world comparisons is always the challenge. A solid state amp, that has the capable power stage capacitors to prevent current starvation, can be perceived as a more powerful amp than one of the same ratings but a weaker power support stage. Most tube amps come equipped with such features, so perception wise, it's tough to make a comparison. Mathematically, if you had common specification generation methods, it could be analyzed. But since that's unlikely, the math won't come out. Trust your ear.

 

[rugerpc]

Loudness perception doesn't work the way most people think it does.

Our ears are marvelous organs but their sensitivity is not linear across our hearing range. The sensitivity is very much frequency dependent.

Have a look at these equal loudness curves and how the signal varies through frequency yo produce the Sam perceived loudness...

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eqloud.html#c1

That site, by the way, is very well done.

 

[drdoom8793]

There is no true way to gauge loudness based on wattage. You can set two 15 watt amps next to each other and they may not be the same in terms of loudness. Now comparing SS vs Tube wattage, if you put a 15w solid state up against a 15w tube amp, the tube amp will pretty much always blow the solid state amp away. But, as Les said, the general rule is that as wattage is doubled, you only get an extra 3 dB. Which complicates things further, as dB is measured on a logarithmic scale, not a linear one.

 

[CVS]

there are always some interesting responses when this topic comes up...

Boy - Do I agree with that

 

[CVS]

Now - One last question - If you have 2 50Watt amp heads and 1 speaker cabinet with 1 - 12" speaker and you also have another speaker cabinet with 2 - 12" speakers in it, will the cabinet with the 2 12" inch speakers be noticeably louder than the cabinet with 1 12" speaker at the same volume level ?- Please assume that all 3 speakers are exactly the same make & model etc.....

 

[László]

Yes. And no.
If I play thru an amp/speaker rig that sounds good to my ears, then if I want that sound again from a different rig it helps to know the specs of the earlier rig.

That's exactly my point.

 

[Deleted member 5962]

Like the old days of specmanship of consumer-grade stereo amplifiers, it's tough to make an apples-to-apples comparison to amplifiers - and preamps - when the methods of stating specs are, well, speculative. Finding a common denominator to make real world comparisons is always the challenge. A solid state amp, that has the capable power stage capacitors to prevent current starvation, can be perceived as a more powerful amp than one of the same ratings but a weaker power support stage. Most tube amps come equipped with such features, so perception wise, it's tough to make a comparison. Mathematically, if you had common specification generation methods, it could be analyzed. But since that's unlikely, the math won't come out. Trust your ear.

BINGO! I always read these "tube watts vs. solid state watts" threads and know what's coming. "Tube is twice as loud as SS per watt," etc., etc. A watt is a watt. Although the specsmanship makes that statement iffy at best, it is true in a literal sense. But it's the power supply differences that make the real differences. Think about how a champ has small transformers and it compresses and runs out of punch... but people love the tone of a good one. When I was modifying Valve Jrs., I added a Hammond OT to mine and it significantly changed the punch and bottom end, and the apparent headroom, but may not have tested at any more watts output.

Most SS amps are cheap and designed cheap. Small transformers, small supply caps, and thus small feeling! A Champ is designed to actually use the small OT/cap thing as a benefit. But I bet you I could take one channel of my modified David Haffler DH120 right now, run a preamp out from one of my guitar amps into that, and easily overpower most of your 100 watt tube amps. But the mods involved massive transformer, HUGE supply caps (and double the number of them) with high speed bypass caps. That that thing has punch that will knock you down and is SUPER fast. I bet that in stereo plugged into 2 4x12s would knock down the walls of a club. I know it would send everyone in a big room running for cover. But the cheap SS amps out there don't have that kind of horsepower, no matter what the wattage rating says.

 

[Boogie]

Now - One last question - If you have 2 50Watt amp heads and 1 speaker cabinet with 1 - 12" speaker and you also have another speaker cabinet with 2 - 12" speakers in it, will the cabinet with the 2 12" inch speakers be noticeably louder than the cabinet with 1 12" speaker at the same volume level ?- Please assume that all 3 speakers are exactly the same make & model etc.....

It depends on where you are taking the SPL reading. 6" from the cone will read the 1x12 as louder output. Backup 30' and the 2x12 will move air farther. More cone surface area to move more air.

 

[shinksma]

Loudness perception doesn't work the way most people think it does.

Our ears are marvelous organs but their sensitivity is not linear across our hearing range. The sensitivity is very much frequency dependent.

Have a look at these equal loudness curves and how the signal varies through frequency yo produce the Sam perceived loudness...

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eqloud.html#c1

That site, by the way, is very well done.

That is an excellent site, and presents the info very succinctly. I just printed that page out to show my colleagues as we mix songs to ensure they understand the ramifications of "needs more bass because I can't really hear it at low volume" etc.

 

[rugerpc]

That is an excellent site, and presents the info very succinctly. I just printed that page out to show my colleagues as we mix songs to ensure they understand the ramifications of "needs more bass because I can't really hear it at low volume" etc.

Yeah, the site is HUGE. And a great resource!

 

[aristotle]

Seems to be some misconceptions here....

First, it really is true, by definition, that two identical signals of the same power, if applied to the same loudspeaker, will generate an identical SPL. Regardless of the particular components used to generate the signals. If you run a test where you can compare a solid state amp and a tube amp through the exact same speaker setup, with the exact same input and with each amp set to produce the maximum rated output power and you hear a loudness difference, then one of the amp manufacturers is lying about the max rated output power.

Second, there is not any more of a difference in frequency response between solid state amps and tube amps than there is between tube amps of different designs. Ruger's link is interesting in that it shows how the ear perceives SPL as a function of frequency, but it doesn't relate to the difference between solid state and tube amps. There is arguably plenty of audible difference in the character of saturated signals, but those differences aren't significant from an overall perspective as it relates to the power spectrum and certainly don't track with the type of circuit used to generate the signal.

Finally, this business of decibels seems to cause more confusion than it needs to. The fact that the human ear doesn't perceive a sound that is twice as "loud" (as measured by SPL) as actually being twice as loud, has nothing to do with the human construct of decibels. It's just that the human hearing system (from ear to brain) tries as best as it can to hear very soft sounds and very loud sounds and everything in between. Nature's solution to that is to make the ear's response non-linear so that loud sounds don't totally overwhelm you while allowing you to still be able to detect really quiet sounds. The decibel, which happens also to be non-linear construct but based on the logarithmic scale, is used to let the human brain deal with numbers of drastically different orders of magnitude without getting overwhelmed. That, and engineers like to do addition and subtraction in their head rather than using pencil and paper to do multiplication and division.

There is just no "factor of 2" or "factor of 10" that has anything to do with solid state versus tubes.