Twl...In a nutshell, you say that errors of the amp and a particular type of speaker are "correlated". (That's the word we academic types use for this well-known situation). Could be so. Thanks for the logical explanation instead of just the usual rant. Unfortunately, not everyone believes that full-range single driver speakers are satisfactory.
As I stated above, the technology of these amplifiers is interesting, but, in your crusade to convince people that tube amps are the best, I suggest that you find a more conventional circuit to tout. |
Tubegroover..OK, I checked it out. The technology (OTL) is interesting.
70 watts at 2 percent distortion, with output impedance of 8.7 ohms, and all for a mere $4500. Sorry, I don't think my Maggies would like that.
So I also checked out the other model called "Siegfried 300B". Into 4 ohms it clips at 8 watts. Distortion, at some unspecified power level, is 4.3 percent. All for only $6950.
You must be kidding. My original (1949) Stromberg-Carlson (pre-HiFi) receiver did better. I know that distortion specs are not the whole story, but when THD gets over 1 percent it becomes a big obstacle to overcome by other virtues. Fear of such an amp doesn't seem at all "irrational" to me. But then, we are all allowed to do some things that aren't rational, but are fun. Enjoy your hobby. |
The high voltages running around in tube amps cause capacitors, both in the power supply and between amplification stages to degrade. Of course tubes degrade.
Reliability, both with regard to performance specs and physical damage, is certainly affected by the degree of skill and care taken in the design and manufacture of the unit, be it tube or solid state, but success is harder to achieve with tubes.
Except for a few audiophiles, transistors have replaced tubes. There must be a reason. |
Tubegroover...If you define an "audiophile" as someone who uses tube equipment, you can say that 100 percent of audiophiles use tube equipment. I have experienced the "cutting edge" of tube design, but the wounds are almost completely healed.
Seriously, I think that we all agree that the best tube equipment, when maintained in tip-top condition is arguably the best. However, the financial investment both for purchase and for maintenance cannot be justified by most people, especially when there is so much good SS equipment available. To use an analogy: a Ferrari is a wonderful performance car, but most people couldn't put up with the constant expensive tweeking needed to keep it running, and they find that a Honda is more satisfactory overall. |
Tubegroover...Perhaps I am just lucky, but the only failures I have ever experienced with transistorized equipment involved a power supply diode (easily fixed, and could also have occured with many tube amps) and a bad wiring connector internal to a Tandberg preamp (unrelated to the amplification devices).
I got into the HiFi hobby (which was what audio was called) about 40 years ago, so I obviously used (and built and repaired) lots of tube gear. I enjoyed it, and some sounded darned good, like Dynaco amps and preamps, but reliability was never a strong suit.
I will check out the Berning zh270 amp, as you suggest. Perhaps tube amps have improved in the last 20 years. |
Twl...I am not all that impressed with academic credentials, although I have some myself. I agree that a listening test would be interesting, but unless I get to an expo it can't happen. Tell me one very simple thing. Are the specs I quoted wrong? How can four percent distortion be covered up with other sonic characteristics? |
Sean...About the pop music performers using tube gear..if the naturally-produced distortion isn't enough, they have a gadget that makes more!
About the RF application...My hearing range does not extend to RF. But, seriously, when Transponders for light aircraft first came out the circuitry was all transistors, except for one Traveling Wave Tube. Guess why the thing was frequently in the avionics shop. Now they (ours anyway) are all solid state.
Tubegroover...What's the point of this amp if you can't use the low feedback configuration. Also, according to Twl, the distortion characteristics of a particular type of speaker (single driver full range) are necessary to cancel out the amplifier distortion. How does this work with Maggies? |
Twl...Digital PWM switching amps are a long way from tubes! Interesting just the same. I am contemplating the Spectron unit, if they agree to put out a 3-channel version.
I gather from the link, that the adverse specs result from aberations which are at too high a frequency to be audible if the speaker were capable of reproducing them, which it isn't. This is a bit different from the tube amps we were discussing. |
Tubegroover...A slight correction..I am not "hung up" about high distortion as you might note from my remark:
"I know that distortion specs are not the whole story, but when THD gets over 1 percent it becomes a big obstacle to overcome by other virtues".
I think that this comment is pretty reasonable.
Regarding degradation of electronic components in tube power amps...back when I was involved with repairing/tweeking these things it was "standard operating procedure" to go through and replace all the interstage coupling capacitors every time you worked on it. I never asked why, but such customs are usually based on experience.
I just observed another thread where MacIntosh amp characteristics, considered good, were attributed to use of output transformers (even though the circuit is solid state). And here we have ingenious circuitry designed to avoid the use of a transformer in a tube circuit. Go figure!!
|
Johnk...It has long been recognized that the fact that tube amplifiers characteristly produce even harmonics, and that even harmonics are typically part of musical instrument sounds, makes their distortion relatively unobjectionable. A violin, for example, might sound not like itself, but still very much like a violin: just one made by a different craftsman and having different harmonic structure. The unmusical harmonics produced by transistor amplifiers require that distortion be at a low level, and it generally is. If so it is inaudible. Both amps can sound good, but the transistor amp sounds like the real violin and the tube amp sounds like a different violin, and the difference will be a richer harmonic structure which gives a lush sound that many people find enjoyable.
Allanbhaganinfo...I'm in western Massachusetts. Are there any Berning dealers? Anywhere? |
Tubegroover...I agree that "piano as a litmus test" is good, but I have never heard a recorded piano that sounds exactly right (and I know what it should sound like because we have a Steinway grand piano in the house). Do you have any suggestion as to a recording (LP, CD, SACD, DVD-A, no tape) that you find exceptionally good, so that I can reduce the effect of that variable in any comparisons? |
