Tubes in Hi-End Preamps


I’m confused. If some of you engineer types could pipe in on this subject, it would be greatly appreciated. I know a little, but not a lot about electricity. I’ve been in the battery industry for 20 years and have taken two semesters of college electronics, so I know just enough to be dangerous.

For 15 years, I’ve been sans preamp. The idea being that I don’t want anything messing up the source signal. That limits me to one source only though, and I’ve finally caved in to the need to be able to access multiple sources with the turn of a knob.

It’ll be nice to finally have hifi sound when I watch DVDs, and I would like to spin vinyl again after 20 years away from analog. To that end, I have an Audio Illusions Modulus 3A unit on its way now.

OK, here’s my question:

Why is it that many higher end preamps, Audio Research for example, that are said to be “neutral” and “transparent” sounding use tubes in their designs? Wouldn’t it be a lot easier and less expensive to build a solid state circuit that produces clean, neutral, and transparent sound? Aren’t tubes supposed to “color” the sound?

I've noticed the presence of a lot more equipment out there (the latest generation of some designs) with tube output sections that are described as not sounding "tubey." What's the point then of having tubes?

I hope I haven’t opened a can of worms here.
blumusician
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Is your Audible Illusions the latest production? If so, it will require a LOT of break-in. I was talking to Art Ferris at Audible Illusions last week. He says the caps he's using are specially made for him, and include lead wound into the cap. they are especially immune to stray interference and vibration, he says. However, they take forever to break in. I got a new one this month and I've been playing it for about 3 weeks. Only now is it starting to open up and reach its potential.

Going back to your question... the previous answers are sound, I think. The tube guys are getting very good at designing circuits that take into account the actual tube behavior at different loads, and in different parts of their response curves. So they're less coloured in sound and more linear in response. And the comment about even-order harmonics being psychoacoustically more benign is a tube advantage. But most of my engineering buddies believe that it's possible to design solid state circuits that will match or exceed the performance of any tube-based preamp, with better objective performance, and greater long-term reliability. Of course, they're the kind of people who see the glass partially full of water as simply being over-designed...

My previous Audible Illusions preamp had a sort-of "holographic" quality that made musicians almost real in my listening room. I liked it, even if it WAS based on artifacts of the design. As a previous poster said, my CD-player sounded much richer and more "real" through the preamp. Of course, since most of my listening is vinyl, I don't really have a choice. But I think you'll like what the Modulus does for you after it finally breaks in!

Hope this helps!
Thanks for all the great input.

Question for Dfhaleycko:

My AI pre that’s in route now is a used one. It’s supposed to be about two years old. After reading more threads on this device, I understand that they eat tubes for breakfast, lunch, and dinner. Any recommendations on what the best replacements would be. Do you think I should listen to the unit first and then decide if I should try retubing or install new tubes right away so that I know I’m getting the best performance from them without guessing?

Also, I understand the AI pre is constantly evolving. Is there any difference between the units being made now from ones just a couple years ago?
"All active and passive devices add distortions; we simply pick the ones that are most consonant with our inner paradigm of what music sounds like." ... "most of my engineering buddies believe that it's possible to design solid state circuits that will match or exceed the performance of any tube-based preamp"... Which makes you wonder if any of the solid state designers are tinkering with adding a bit of even harmonic disortion to voice for what is percieved as neutrality or as depth in midrange.
neutrality does not exist. it is unattainable. all components are colored. choose your favorite coloration.

unfortunately many allegedly "neutral" components have a character which is evident after extensive listening.