tube Watts vs solid state Watts

A Watt is a Watt.. No doubt.. This might be slightly off topic,
However I have 20 watt tube monos that Shocked the H3LL out of me, that put out more clean power and musical response than 200 watt SS monos that by the way costed in the 4 k range. Tube power is very different regardless how many here want to say its the same.. it is on paper but seems to be very different in actual use..

Another example is why would a 50 watt Marshall Guitar head amp just need 50 watts to go into concert levels? Yes a big reason is the far more efficient drivers, and the limited frequency range being not too deep of bass taxing the amp, but fact is I would still take a 50 watt marshall over a 300 watt peavy SS and walk all over it!

So don't be afraid of low power Class A tubes, they still pull way less power from the outlet than a 200 watt boat anchor like a adcom or mcintosh that dims the lights in the house when turned on, just make sure you have efficient speakers and it will not matter. Don't get me wrong I have had great amps from both camps, but low powered tubes are probably much more impressive on first listen due to very little power and big sound, vs. many solid state amps seeming to be fairly closed in and restricted regardless of power ratings. Just another partial audio mystery to most, and even urban legends that small tubes can't produce acoustical power, mostly they do more so until you get into some really serious solid state stuff.

Undertow: what is your explanation for these a bit counter intuitive findings? So those people who say that tube Watts and solid state Watts are not alike should be taken seriously?

Chris

Dazzdax, simply put I think it has to do with a
200 watt SS will put out about 10 watts of good power at lower levels, and it is not continously putting out 200 watts at all gain levels. It switches into this high wattage in peaks..

Class A tubes are running 100% at output at all times, same temperature, same stress, same outlet power draw etc...

When a SS hits it then taxes your power system in the house very quickly and can sound less impactful for the instantaneous peaks they actually perform on and off.. Tubes seem to be much more "Consistant" watts..

But measurably I am sure both would say the same on a meteer, but two totally different devices deriving these watts.

By the way interestingly I have shut down thermally exhausted and or overheated several ample powered SS devices in my day :-)

Never have I ran out of Tube power.. but again Tubes burn out due to they normally run 100% of their output at all times including Idle, Basically what I find is the only way a TUbe device fails is when the tube reaches the end of its life, which yes can be prematurly by other bad components in the unit giving out, or just the tube being not so great in the first place... However whether they would blow up under Hi volume or idle, I think it would normally just be by coincidence if they fail under hi power output to the speakers, it just could happen.

I have run several SS devices out of steam or shut them down with no better volume and actually more compressed volume than you get with much lower Tube power. Probably due to most Tube designs transformers and power supplies are Way overbuilt, and SS are built to handle their output levels in steps and part time peaks.

I am not an engineer, and actually am just going on my observations, but don't be shocked to see many tubes putting down some nasty power and seeming to be even more effortless with 10 watts opposed to 100 or even 1000 watts from solid state.. Again I am sure a 10 k, or 30 k SS device it would be no problem showing the true colors of full on SS power no doubt, and reliability is I am sure very excellent..

I am sure many more on this forum knows much more, just from some experience I have had this seem to be interesting and sometimes misunderstood.. Hey My uncle had a 30 watt Harman Kardon Receiver when I was a kid from the mid 80's and it had better sound and power output up to top output over a brand new very well known Receiver we tried 2 years ago at 250 watts and that I could not believe ~! So go figure.

While on one level a watt is just a watt, we also have to take into account how humans hear. As Duke noted early in the thread, we perceive "loudness" far more on the average level than peaks.

Take the following example with a 20 watt tube amp and a 20 watt transistor. Both are plugging along into a 87 dB efficient speaker. We're using roughly 10 watts to crank out a loud 96 - 97 dB average volume. We encounter a 3 dB peak in the music which requires doubling the needed power. Both amps deliver their maximum unclipped volume without clipping.

However, if that is a 6 dB peak, we now need 40 watts so both amps clip. The tube amp will give a better behaved clip that is less likely to draw attention to itself so we leave the volume control alone. The transistor amp clips harshly. Many people will respond to that harshness by turning the volume down until the harsh sound goes away.

This is the mechanism that causes many to say tube amps sound more powerful, watt for watt, than a transistor amp. Nothing real complicated going on.

Keep in mind that powerful transistor amps are widely available so if well matched with the speakers, this isn't a big problem these days.

As for transistors delivering more current & power as impedance drops, this only happens at certain frequencies, generally in a reasonably narrow band. You only get the extra power if your peak just happens to be composed primarily of energy at the correct frequencies. Music isn't generally composed and played with much consideration that the loud parts conform to a particular frequency profile. As such, it is a roll of the dice as to whether a transistor's extra power at lower impedances will be a benefit when playing any given piece of music.

All of that said, one is still better off buying an amp of appropriate power for your speakers and listening habits. The better solution is to avoid clipping and the need for impedance-related power all together.