Can tube preamps be as 'detailed' sounding as ss?

Zaikesman, I appreciate that you have a level headed attitude towards the sport. If you look back at my original post, you will find in the second paragraph the acronym 'IOW', which is to say that I was indeed commenting on the fact that many audiophiles accept brightness in lieu of detail.

I have a customer now that is objecting to the idea of a 'detailed' preamp, on account of he does not like brightness. So I am commenting on a very real phenomena (although I don't think you were objecting to that in my post).

I do think you were objecting to my initial assertion that many ss preamps get identified as detailed because the high/odd-ordered harmonics that they make (in very small amounts) are interpreted by human ears as loudness cues. This does happen to be a fact, as the human ear uses the higher (+9th - +17th) odd orders to tell how loud a sound is.

One time (30 years ago) I was servicing a transistor amplifier and had it on the bench VU meter. I noticed that when the amp was distorting heavily (malfunctioning), the -30db signal that it struggled to make sounded louder than the 0 VU signal it made when it worked correctly. I later found out that General Electric had proven in the 1960s the human senstivity to the harmonics just mentioned. Oddly, many audiophiles are not aware of this study!

Admission: I didn't, and still don't, know what the acronym 'IOW' means...

About the amp thing, I play electric guitar, which as you know is often intentionally distorted, either via amp overdrive or by a fuzzbox, and think I'd have a pretty good sense of it if heavily distorted sound were actually perceived as being louder than undistorted sound measuring 30dB higher in level. I understand that the ear/brain is supposed to increasingly identify and object to harmonic distortion with increasing order. However, I don't think it's universally true that SS gear produces more of this content, although it may be true that tube gear generally produces more low-order content which helps mask it. (Although what you're alleging sounds as if it might have more to do with TIM than THD.) You are right though, I'm not aware that the ear/brain uses harmonic content to help determine loudness -- do you have a citation on this?

IOW means 'in other words'.

The 'citation' I've been referring to is the study by General Electric that was done back in the 1960s. In it, they found that people will tolerate quite a bit of even-ordered harmonics added (up to 40%), but were not tolerent at all of odd orders, objecting to vanishingly small levels. The study showed that the human ear uses odd ordered harmonics as the primary means for determing loudness.

What this means for audio design is that designing with an eye to remove this harmonic content (+9th odd orders) will result in a more relaxed presentation.

If you want to see how this works in the tubes vs transistor thing, all you would have to do is run a sine wave into a preamp, run it up to clipping and view the output with a scope- the tube unit will have a rounded waveform at clipping, the transistor unit will look on a scope like somebody cut off the top of the waveform with a scissors. This 'cut off' area is a place where odd ordered harmonics abound.

Semiconductors, even FETs, by their very nature tend to generate these harmonics more than tubes, even if not being overloaded. It is something that comes with the territory in things solid state.

My active solid state preamps (H2O Fire) couldn't be more clear, with no discernible foreign harmonics whatsoever. What they are, I don't know. The builder says, unconventional. Whatever, it works.

Atmasphere: Most tubes go into "soft clipping" ( rounded edges ) because they don't have the necessary speed / bandwidth to reproduce the sharp edges that make up a heavily clipped sine wave aka a square wave. Then again, i'm not telling you anything that you don't already know, so this is really for everyone else reading this thread : )

Other than that, i've always been a proponent of having "MEGA" overhead in system capacity. I learned a LONG time ago that it is not sheer spl's that make things sound "loud" and / or "aggressive", but distortion. By using high powered amps that are never pushed, and speakers that aren't easily driven into compression, one can listen at astonishingly high spl's with little to no fatigue. Not only that, but it doesn't sound nearly as loud as it really is. That's because the system is free of distortion, which is what adds the apparent volume that brings both fatigue and ear strain with it.

As far as Muralman's comments go, most good quality switching amps can sound quite clean even when spl's are roaring. This has to do with their reduced duty cycle, which minimizes thermal stress. When it comes to SS amps, the faster that you can dissipate heat, the better off you are. Both sonically and in terms of product lifespan. Sean
>