Can tube amps give true high end bass?

Damping factor does not play much of a role in the sound of a speaker, previous posts notwithstanding! In fact damping factor is really a spec that gets touted a lot, but would seem to be mythological in its effects.

Damping factor is a means of expressing the output impedance of an amplifier. It is true that as the output impedance of the amp gets closer to the load impedance, that distortion rises, but the idea that the amp 'looses control' of the speaker is a myth, really a sort of chicken and egg thing.

In a conventional speaker, the voice coil requires a certain amount of power in order to displace the speaker. Any amp, regardless of its 'damping factor' that can make the power can displace the cone the same amount. At any and *ALL* cone positions that are possible, the cone will be in that position *because of the power from the amplifier directing it to that position*.

Note also that all bass waveforms (where 'damping factor' is touted as an issue) are real-world mathematical functions, and therefore continuous in nature. The are no worries about 'stopping' and 'starting'- unless you listen to some very weird, amusical stuff that no-body has made up yet :)

Most speakers if heavily damped will in fact not be able to reproduce the bass waveform. This is one of the reasons that high damping factor amplifiers tend to be bass shy, while at the same time having a sort of 'punch' but being otherwise bereft of bass definition and tone. Problematic, as amplifiers with a high output impedance can on some speakers fail to cut power in the frequency band where the speaker/cabinet system develops resonance.

How is this solved? It turns out that there are 2 paradigms of design, test and measurement in competition in the world of audio today. *IF* you mix equipment from one paradigm with that of the other, you will have a mismatch- it will not work right. see:

http://www.atma-sphere.com/papers/paradigm_paper2.html

for a more in-depth explanation of the differences in these paradigms.

BTW there are tube amps with full power to 1Hz and able to reproduce 20Hz square waves with no measurable tilt. This bandwidth has nothing to do with power or output impedance FWIW.

Atma

Most speakers if heavily damped will in fact not be able to reproduce the bass waveform.

A tiny clarification:
"overdamped" could be the result of a combined effect of driver & amp. I.e., if one uses a highly damped Lowther PM4 (x-max 1mm, flux: 24.000 gauss, quoted Fs= ~35Hz) for bass duty and drives this with a low output impedance amp, the audible low frequency result will be... inaudible. The amp-driver combo is over-damped (i.e. the electrical q is approaching 0 :) ).
This is just for the sake of example, no-one to my knowledge uses a PM4 for bass -- but I think it illustrates what atma is referring to.
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T_BONE: Another question back at you would be... how much tube power (watts vs output impedance) would one need to adequately power an 8ohm 96db woofer? say, the way a 40W solid state amp might...

Theoretically, Watts are exactly the same whether they come from a solid-state or a tube amp, so a 40 Watt tube should produce the same acoustic output as a 40 Watt SS amplifier. In practice, it depends on how conservative are both manufacturers on their power specs, but the differences should be negligible even for differences up to tens of percent (for example, a 40 W SS amp vs. a 30-60 W tube amp).

A more relevant factor is: How loud you like your music? With 40 Watts, you can have undistorted peak acoustic levels of about 112 dB at 1 meter with your speaker in anechoic conditions. Adding the other speaker and the room gain, you could easily surpass 120 dB peaks in your seat!! Ironically, at such loud levels a solid-state amplifier with better bass extension might stress your speakers and cause them to produce a phenomenon known as "Doppler distortion" (don't confuse this with another, notorious concept mentioned in the H-thread). In this case, a tube amplifier having weaker bass would produce a cleaner, more enjoyable sound, provoking the logical conclusion that the tube amp sounds "better" than the more accurate solid-state amp. The morals of the story is: If you want powerful low bass from your amplifier, first make sure your speakers can handle it!

Regards,

""The are no worries about 'stopping' and 'starting'- unless you listen to some very weird, amusical stuff that no-body has made up yet :)""

I don't agree with this.Every bass drum pedal hit is a sudden start and stop.Of course,it is an electric waveform,but our ear hears it as "start and stop".
And if you have dynamic double bass (in heavy metal for ex.),it will sound better with SS.More tight and controlled.

Atma is obviously an expert and knows more on subject than the rest of us.But i only report what i heard myself.
I thought damping factor was a part of it,and i am still not convinced it isn't.I read Atma's post a few times,and i'm still gonna get into that.But obviously Peak and Recovery time is better with SS.
I like tube amps more,espec. SET,but SS also has its strong points.

Audiobb, I play heavy metal too and I also have a few friends in the heavy metal world and I opened for Therion when they toured here a couple of years ago. The start and stop of a Kick drum is *way* too slow for any sort of stop and start that might actually be a 'damping factor' phemon! If you look at a bass drum waveform, you will see that even in a fast double bass passage, the waveform dies out as the kicker pedal is damping the waveform. Speakers are a whole lot faster than that: even a 15" has bandwidth to 500-800Hz. The bass drum (actually a typical area where 'damping factor' is brought up) is a red herring.

Jmaldonado's comment about bass extension is non-sensical, although I have to guess that it is only based on his experience. So I will share an experience of our own:

Some years back we used the Snell Model B for our main system. The speaker is full range, and was easily driven by our smaller M-60, although it was only 89 db. We went through 4 sets of woofers before Snell replaced the woofers with a re-engineered set that was more durable. We were not damaging the voice coils- the spider part of the suspension was failing, due to the excursions we were putting the speaker through (we like to play stuff with impressive bass tracks, as with 1 Hz full power in our amps, the bass we get is a strong point in our products). Snell told us that they had the same problem with mastering houses that were doing lots of dance tracks with heavy bass (we were playing that sort of material too)- see http://www.atma-sphere.com/awards/bya/index.html
for some of the discography.

So tube amps can put as much excursion on a speaker cone as a transistor amp, FWIW. In our case, in repeated demos with transistor amps, I have yet to see one that has proper bass extension. So while I accept that transistor amps can play bass, I do not accept that they can do it any better than a proper tube amp.