People who are Irrationally Afraid of tube amps


Recently I've had a tube amp For Sale on this site. It's a well respected, great amp from a major mfg. I've owned it for 3 years, with absolutely no problems, only enjoyment. I'm only selling it because I sold the speakers I used it with, & my current speakers are a lot more power-hungry. And it's the 2nd tube amp I've owned, my first being a really early model VTL ST-85 that was several years old when I bought it, then I had it for 5 years, & the only problem I had in all that time was replacing a fuse once. And I know almost nothing about electronics, but I learned how to use a multi-meter & successfully biased & replaced tubes in both amps.

Here's the thing: Almost every person who has written to me about my amp for sale asks a zillion questions, you know the routine, e-mails back & forth, then finally says they are too freaked out at the possibility of replacing tubes someday to buy it, whining about the (relatively modest) expense, etc. (And my amp has new tubes!!). Now, these queries are from presumably experienced A'goners because most of them have a large no. of positive feedback ratings here. I mean, we're not dealing with the average shopper at Circuit City, presumably.

My questions are: 1. Why do experienced A'goners waste so much time shopping for tube gear if they're freaked out over the potential traumatic effect that replacing tubes may have on them someday? There's plenty of SS gear FS if that's what they want. 2. Why do many even relatively experienced audiophiles still believe in the "tube hassles" myth? 3. Are there no tube afficiandos who are willing to put up with a minor inconvience every few years?

I feel like putting a warning in the next ad I run for a tube amp: WARNING: THIS DEVICE CONTAINS HIGHLY VOLATILE "TUBES", WHICH MAY BLOW AT ANY SECOND & COULD DESTROY YOUR ENTIRE NEIGHBORHOOD! USE AT YOUR OWN PERIL, PREFERABLY IN A NON-POPULATED AREA. EVEN IF THEY DON'T KILL YOU, THE TRAUMA OF REPLACING THE "TUBES" SOMEDAY COULD REQUIRE YEARS OF PSYCHOTHERAPY, & MAY BANKRUPT YOU & YOUR ENTIRE FAMILY.

Well, at least that might discourage the "tire kickers". Now, if I could just afford those Cary 805C mono-blocs I've been wanting for years........& thanks for listening to my rant!
steveaudio
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?
I have to admit, Eldartfords arguments don't make my fears seem that irrational.
The specs you quoted are from the Berning website, and are the typical David Berning conservative type specs, which he always shows "worst case" types of figures. The distortion figures are at clipping for that amp. It is stated that the figures are lower at more normal outputs.

In addition, nearly all the distortion is located at the 2nd harmonic, which is where we want it to be when using the single-driver loudspeakers that this type of amp is designed to typically drive. For more info on this, see Eduardo DeLima's article "Why Single Ended Amplifiers?" on the web. This is an article with detailed test info which shows the complementary relationships between single driver loudspeakers and single-ended amplifiers, with both showing harmonic distortion profiles predominating at the 2nd harmonic. In both theory and testing, it was shown that this complementary relationship will cause the self-cancellation of some(and in most cases the majority) or all the THD in the AMP/SPEAKER combination. It shows the folly of attempting to extrapolate any meaning from single component distortion specifications, when these may not hold true when exhibited in a system context. True, most other systems with wide spectrum harmonic distortion profiles(solid state) are purely additive in distortion, due to their harmonic distortion being all over the place. But in this case, the THD is not purely additive between these types of components, and in fact is subtractive in most cases, and even totally self-cancelling in the most perfect case(not likely). So it is concievable, and shown to be proven by this article, that the case of single-ended amp and single driver speaker have a unique relationship that can actually cause the SYSTEM to have a measureably and audibly lower distortion than ANY other type of amp/speaker system regardless of technology or cost.

This is where the spec game is totally lost. Nobody measures system distortion, only individual component distortion. They see half the info, and try to make definitive statements. This is also why I urge listening testing.

I have fought this "spec battle" for over 20 years, and there is always someone who "knows it all" because he looked at some scope trace, or read some spec sheet, or rides a test bench, and thinks what he learned from that is applicable to audio. The specs are a trap. They are a trap that stops people from learning the full truth. A marketing ploy.

The "scientific minded" people are the first to fall into this trap. They are numbers minded, and get suckered right in. They use the specs to "show why this can't be so". It's a magic show. They aren't showing you everything. They are showing you just enough to make you think their way.

I have written this type of post numerous times on this forum. And there is always another person coming along with the spec argument. You cannot rely on any spec, except maybe 120VAC 60Hz input. They are measured in an "out of context" testing regime, and mean nothing in regard to how they perform in a system context. To place a big trust in these specs will lead you down the primrose path to poor sound.

Maybe I sound harsh, but I am really trying to be helpful and informative. I didn't fall off the turnip truck yesterday. I know all about testing methodology, meters and scopes, what they do and what they don't do. I was once a "spec believer". Then I woke up, when somebody showed me the flaw in it. Now I'm doing the same for others. Some won't listen.
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.