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amplification = to tube or not to tube ,that is the question

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  • amplification = to tube or not to tube ,that is the question

    tube equipment always seems to be the choice at audio shows , music only applications , what's the reason ?
    surely there are high end companies out there that make pre-amps and amps that could compete with or possibly outperform tubes !?

  • #2
    Tube are by and large more expensive than SS, audiophools equate quality with price. SS eclipsed tubes in performance roughly 40 years ago.


    • #3
      My vague memory is that Sony (?) developed a Field Effect Transistor or "MOS-FET" about 40 years ago which really made an impact on people who'd always believed that tube amps 'sounded better'.

      In the days before larger amplifiers became the norm, maybe early 70s, most affordable transistor amps seemed to be 10-20 watts RMS. Combined with speakers which liked power, many people including me drove their amp into 'clipping', which resulted in harsh distortion. Supposedly, valve amps didn't and don't have such distortion when driven too hard.

      I've never driven my old Yamaha into clipping as the volume/gain knob only has to go half way and it's too loud.

      These days I don't know anyone with a big valve amp: no one I know could afford them.


      Last edited by Geoff Millar; 08-18-2019, 06:59 AM.


      • #4
        I have read that solid-state amplifiers usually employ negative feedback which serves to control loudspeaker motion in a way that tube amplifiers do not. The example given was to tap a loudspeaker with your finger and then tap it again with the input terminals shorted with a screwdriver held against them. Supposedly with the screwdriver, the cone would make a dull thud but without the screwdriver, the cone would sound like you had tapped a drum. Is this baloney or does it have something to do with how amplifiers and loudspeaker mechanisms interact and consequently why tubes might be favored by "audiophiles"? (who have more money than sense, and whose appreciation of the difference between a recording of Ella Fitzgerald and Ella Fitzgerald in concert has nothing to do with the fact they could afford the tickets and caught her act six times)


        • #5
          IIRC, tube amps can, like SS amps, employ negative feedback. I could be wrong.

          donwc I built a universal tube preamp called the 4s found here, Although not ideal for every 12a*7 tube, it allows you to row about half a dozen of them. If you find a tube you prefer, you can then make a few changes so it operates optimally for that tube.

          There was one old tube in particular that was literally magic on Natalie Merchant, Diana Kraull, and anything containing mostly vocals.

          I'm pretty sure that tube was bad.

          What it taught me is that distortion and a lot of other specs we deem most important, may, to our ears, not be that important. In fact, I'll go out on a limb and say that our ears may very well find certain types of distortion pleasing and thus, prefer that type of sound over technically superior audio reproduction.

          I am a total solder nube, but with lots of coaching from Tom_s and PWRRWD over on MAC/DIY, I was able to complete the project with no smoke or anything blowing up. If you are interested in the 'tube' sound and the 'tube rowing experience', I suggest you try and build something like this inexpensive tube preamp and find out if tubes do, or do not, make you have an eargasm.

          Link to DIY/MAC universal preamp build


          • #6
            Originally posted by Kornbread View Post
            The one instance where tubes are decidedly better than SS is in musical instrument amps, and then only when they're clipping. SS can sound the same, but only with additional processing, mainly compression, that tubes do on their own. There are preferences within the tube amp genre too, with those made before the mid 1960s being the most sought after. The reason is that they used tube rectifiers, not solid state diodes, in their power supplies. That added another layer of soft knee compression to the sound.


            • #7
              Totally up to you. Some tube equipment doesn’t sound “tubey” at all. Some sound very lush, which is just likely inflated second harmonic distortion. It is technically distortion but it is perceived as pleasant. It depends what you want. Some people want flat, lab-sterile, .001% thd setups, some like the smiley face eq, and some like warm sound commonly associated with tubes.

              I personally like the cliche tube sound. I have found I like the control over the woofers and bass from a solid state. Other things to consider is tube amps typically are fussier about speaker impedance swings and phase.

              You can also greatly change the sound of a tube amp by switching the brand of tube. This could be good or bad. Also consider tubes are wear items.

              Personally I think the best option for numerous reasons that are all nothing more than my opinion is using a tube preamp and a solid state amp. Ymmv


              • #8
                For sound engineering advice you should read the discussion of tubes on Rod Elliottts sitre Elliott Sound Products; there is quite a lot there.




                • #9
                  I built a tube amp and preamp from kits. I didn't really find them exceptional except in how much they cost. They sit under the bed with the rest of my excess stuff.

                  The amp gets hot, and if you remove the cover the tubes look cool.

                  dwight yoakam and flaco jimenez carmelita - YouTube


                  • #10
                    Originally posted by djg View Post
                    I would not but a really expensive tube amp thinking it "sounded" better. I would buy/build a moderately priced one and think I might subjectively like the sound better but the primary reason would be because it would look cool.


                    • #11


                      • #12
                        What people lose sight of is that tube amps aren't expensive because they're better. They're expensive because their obsolete technology makes the parts they're built from expensive. I can remember when tube testers were in just about every corner drugstore, because tubes were in everything, even car radios. Now they're only used in audio gear, and a very small percentage of audio gear at that. The economy of scale that once made tubes, high voltage power transformers, output transformers and high voltage capacitors affordable hasn't existed for decades. If not for the musical instrument amp market the situation would be even worse, chances are there wouldn't be any consumer gear with tubes.


                        • #13

                          That does look kool! Sexy ...

                          Sound and a light show 1kw tube amp.


                          • #14


                            • #15
                              It just got out of hand. I was going to build one of those little Tube Depot amps but it escalated.