tube watts vs solid state watts


(newbie here)...Does a 60 tube watt amplifier produce the same perceived "loudness" as a 60 watt solid state amplifier with the same speaker/preamp level?
samuellaudio
When comparing solid state or tube amps, be aware that the rated output is based on impedance. Speakers vary greatly in both impedance and efficiency, making this a difficult decision to make if looking at specifications without every fact revealed.

What follows is a perfect example of how output power ratings can be confusing to the buyer after auditioning and not getting the results they expected.

Compare a large solid state amp rated at 1000 watts compared to a 200 watt Atma-Sphere OTL. For the speaker, an early (1990) pair of A-1 Sound-Lab.

The 1000 watt solid state amp drops to about 75 watts at the most difficult to drive bass frequencies (80 HZ and below) as the impedance rises to 56 ohms (+). The Atma-Sphere MA-2 OTL will produce more than 200 watts into that same difficult load.

The Atma-Sphere will have problems with that same speaker at 22K because the load is now 2 Ohms, but since there is so little music at 22K it becomes irrelevant. The outcome is the 1000 watt amp is clipping much of the time and the Atma-Sphere will drive the paint off the wall.

The listener is confused, why more volume with 200 watts than 1000? The problem begins with most speakers impedance being listed as "nominal." The actual full bandwidth impedance is seldom revealed.

Some speaker designs are extremely low impedance (below 2 ohms) and other vary at different points in the frequency spectrum. Yet another reason to choose an amp design that's sound appeals (transistor or tube) and try it in YOUR system with YOUR speakers to see if the combo flies.
In my opinion Tube amps appear to so a better job of driving a load than most average solid state amps and thus may appear "louder". In addition most tube amps like my Audio Research VT60SE are so beautifully made and include such heavy metal power supplies etc, that they tend to sound more powerful.
You boys are filthy, filthy, filthy! Minds in the gutter at all times eh? The reference was to the movie "Spinal Tap"...I guess no one's seen it!? Y'all should be ashamed. This is a public forum after all!

Marco
This is a public forum after all!
Marco, I hate to red pen you, but did you intend to include the L in "public"? After all, if yours goes to 11...
Actually, most tube amps run into difficulty driving low impedance loads and put out less power at 4 and 2 ohms than most equivalent solid-state designs (many of which double power into 4 ohms and then double again into 2 ohms). So if you have a well designed ss amp rated at 50Wpc into 8 ohms it could put out 100Wpc into 4ohms and up to 200Wpc into 2ohms. A typical tube amp rated at 50Wpc will put out nearly the same 50Wpc at 4ohms and much less power (maybe 25 watts) at 2 ohms. That said, a few tube amps are specifically designed to drive low-impedance loads more efficiently. I believe that VTL has a few models optimized to drive 4-ohm loads.

Additionally, tube amps traditionally have terrible damping factors which is why their bass is loose and indistinct compared to decent solid-state.