tube Watts vs solid state Watts

Perceived loudness and amplifier wattage is not the same thing. Agreed a watt is a watt, no matter what (excuse the pun).

On a thread some time ago (I am to lazy to search now) a couple of posters stated that even if the fundamental remains the same, humans will perceive an increase in volume when the even ordered harmonics increase in db. So when a tube amp clips in a benign fashion, additional gain will allow the harmonics to increase in db, allowing the listener to hear an increase in volume/loudness.

I use a 12wpc SE tube amp and it most certainly plays louder than my 25wpc chip or 35wpc transistor amp. So while it is technically a watt is measured the same no matter what amplifier topology we talk about, for a specific rating a tube amp will deliver substantially more perceived loudness than a transistor amplifier.

Regards
Paul

And what about pure class A solid state Watts and class B Watts? Many audiophiles (who are often non techies) say that a 50W pure class A solid state amp is comparable to a let's say 200W class B amp. Is this bullshit? Why do people give that kind of deceiving comments?

Chris

When comparing two amps, I think the power rating is the power rating - no matter whether Class A or B as long as you are comparing at the same THD. Perhaps the discrepancy is due to type of distortion as mentioned above because Class A and Class B definitely have different distortion characterisitics. But I also feel (and this applies to tube amps too) that tonality can play a role. I often hear that such-and-such low-power tube amp has better bass than some big SS amps does and that gives the impression of more power.

Another thing I have heard a few times now is that tubes are able to produce a huge amount of power for a very short amount of time - much moreso than SS amps can. I am not sure about the validity of this claim but from a signal level conduction resistance point of view, it makes sense since you are comparing vacuum with "sand."

But when you are dealing with human perception, everything gets cloudy. Everyone is entitled to their opinion so take what you hear and read with a grain of salt but don't get upset by it. :)

Arthur

In a tube amp there is (usually) an output transformer, and it, as much as the power supply or tubes, will limit the distortion-free power output of the amp. The real heart of a tube amp is its transformer. Good ones are few which is why OTL amps exist.

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.