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?


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!
I had a tube once, two tubes actually, in a counterpoint 2000 preamp. It was half solid state, half tube.
I loved it with all my heart, when it was working.
I sold it for junk after it stopped working again... (It sat in my closet, broken, as an object of scorn for two years, traded it for a Pioneer P2 Laserdisc player to the folks who sold it to me)
I decided never again.(at least until I win the lotto)
The fooling around to make tubes work is a full time lifestyle. And EXPENSIVE!!! (I KNOW it is not that bad, but that is how it felt)
I can live with the sound of solid state, knowing that the stuff is going to last 'till I am mouldering in my grave. (usually)
Perhaps your irritation with the tire-kickers is showing up in subtle ways and that is also a reason they back out???
After all, they certainly SEEMED interested, didn't they?
I like the way tubes sound. That is why I bought McIntosh SS. Best of both worlds.
I made the switch to tubes quite awhile back, and I have found my tube gear to be just as reliable as my SS stuff. I have changed tubes, but not because any of them went bad. I just wanted to get better tubes for the sound quality. I have never had a tube go bad in any of my tube gear.

My amps have been self-biasing, so I don't have to fuss with that, and it is just as easy to use as any SS amp. I feel reliability of the tube gear I've had is not an issue.
Most of the "reliability factor" or lack of it that goes along with tube gear is due to poor design, cut-corner build and too many bean-counters. If these products were built the way that the engineers designed them, they would probably be more reliable. The bean-counters say "this product is too expensive to produce and we won't make enough product, so find some way to knock the cost down by XX percent and we can put it into production". The end result is that they use 1/4 watt resistors when they need 1/2 watt, use plastic where it should be ceramic, etc...

Then you get into the guys that insist on keeping the circuit as short and simple as possible. Whie this may be a valid approach, it leaves little room for safety factors and protection circuitry. Even if one were to build such a design like the proverbial "brick out-house", when something fails, it fails BIG-TIME !!!

Bare in mind that this also takes place in SS gear. Since tubes run MUCH higher voltage though, the potential for increased arcing and / or "flame out" is drastically increased.

As to Elizabeth's comments above, Counterpoint was known for not being a real reliable product line. While many people loved the sound of these products, many also cursed them for all the problems that they brought with them. As far as amps go, i think that ARC's are the "king" of "spitting fire". Then again, ARC has probably sold more tube amps than any other manufacturer, so that could account for why we hear about them "putting on a fire & light show" more so than other brands. Sean
going through two amps in several years hardly sounds like a trouble free situation.
Tubes are very reliable, especially in line level applications (preamps, DACs, etc.) and even tube power amps can be made to be as reliable as solid state power amps. Sean makes some good points above as to why this isn't always the case. My main grip against tube power amps is that they are very big, require gobs of power and throw off alot of heat. To the extent that anything in the audiophile world is practical, tube power amps are not that practical. But then again, there is the Berning.
I think it must be a mental disorder similiar to claustra-phobia.....perhaps....let's call it popatube-aphobia. Do you think this phobia could be documented for the Medical Journals? Personally...I believe that good tube design to be a whole lot more reliable than SS stuff.Back in the 70's I blew up a phase linear 700b on more than 1 occasion as well as an ampzilla and a pair of Kenwood monoblocks.Built a dynakit st-70 back in 1967 that is still used every day in my kitchen.Other than replacing tubes for performance,I have never had an issue with it.I still use an ARC sp-10 preamp from 1985 and have never had a single problem.I foolishly sold the D-79b last year. Same thing...never had a problem.There are literally multi- thousands of old classic Macintosh,Marantz,Dynas,Scotts,Fischers etc from the 50's and 60,s in fine operation as we speak.Do you think any of the ss stuff of the era is still working today? I doubt it!
Since I've had a tube line stage, tube phono stage, SET monoblocks, and tube tuner for years, all I can say about the the tubophobes is, "it's their loss." I admit I had a tube DAC that was frequently in the shop, but its problems had nothing to do with the tubes.
Experienced AudioGoners? Not everyone is equally experienced with all kinds of gear. We solid state folks keep hearing that tubes are king (I've heard tubes and ss in many forms and it really is a matter of personal tradeoffs and preferences IMHO). So, some of us want to extend a toe into the water but we are nervous about it and need some reassurances and background to help with the buying decision. At the same time, we want things cheap. There's the rub: We want the advice and handholding of a dealer with the pricing of a web purchase.

Steveaudio, since it doesn't seem you wish to assume a mentoring role (and there's no reason you should), simply let folks know at the first email that you are willing to describe the equipment but will not offer advice or guidance. Don't blame folks for asking, just about everyone wants as much as they can get for free ;-)
One reason some people I know invoke is that they are not so much afraid of tubes as confused by differing opinions as to which tubes are "best." I've seen a tube aficionados argue ad nauseum about which tubes (NOS vs. this brand vs. that brand) are best for such-and-such a piece of equipment. It's enought to give a novice a splitting headache.
I'm one of those that you talk about. Although I've never tire kicked a tube amp, I have thought about trying one occasionally. I've owned tube preamps, phono stges and cd players with no problems or complaints. However, tube amps do take tube problems up a notch, IMHO. I've been in this hobby over 25 years, and I'm afraid to try one, there, I said it. I've heard of the 'problems', and they do seem to be more likely to occur in a tube amp than a SS amp. Power tubes tend to cost more to replace than line stage tubes, and from what I've read over the years, are more likely to cause 'flame-outs'. Possibly even taking out equipment down stream, such as a speaker driver. Some, like myself, are streched as thin as we can finacially to get the best that we can, but cannot afford any kind of reliability issues. I buy everything used, most from Agon. If a tube flames out and takes out a driver, it could take months for me to afford to get my system up and running again, finacially. I don't have a second system, or spare parts (preamps, amps, etc) laying around. Now maybe I'm wrong and I should downgrade from BAT, Classe, and Threshold to Rotel and NAD so I can have money to afford second systems and spare parts, but that's my choice. To squeeze every last penny into one system. Reliability becomes much more important in a situation like this though.

Wow, what a great forum. Everyone seems to be sincerely in touch with their feelings and yet so civilized. Is this really another Audiogon tube/solid state issue? Very refreshing. Well done ladies and gentlemen.

Most of the outright failures I have experienced (aside from stupid abuse/misoperation) have been with SS amps, not tube amps.


1: Musical Fidelity X-A1 integrated amp (one power section dead following < 1200 hours of usage - too bad as it sounded very nice with efficient speakers).

2. Musical Fidelity AS-100 power amp (loud hum following < 5 hours usage - returned to Audio Advisor).

3. Hafler DH-500 power amp (power cord interface became brittle and broke < 5 years from manufacture - this was an easy 5 minute diagnosis/fix once I popped the cover). Primarily for PA use, but nice with Hi-fi also.

4. Quad 303 power amp (caps and some of the resistors shot < 8 years from the manufacture date (too much of a hassle to repair per a friend/tech).

5. Quad 33 preamp (same as the 303 power amp above - I ended trading both units, with full disclosure, for a painting:-).

6. Advent 300 receiver (never a problem with sporatic usage over a 9-10 years period).

7. Phase Linear 400 power amp (had a tendency to shut down when continuously operated for approx. 6+ hours whether it be PA or Hifi use - otherwise reliable for lesser periods - bought it new and used it for a couple of years - preferred Dynaco ST-70's in mono mode for PA use as they sounded better and they did not shut down).

Tube Amps:

1: Various RCA, Emerson, etc., stereo console integrated, power and preamps (5-10 years old @ time of usage and no problems with Hi-fi use - blew up a few using them as guitar amps - 10 years old and clueless @ the time).

2. Eico HF-81 integrated (no problems and recapped after 10-12 years - standard maintenance for most any amp).

3. Dynaco Stereo 70 power amps (owned 4 of these and no problems other than having 2 people run/crank a signal through 2 of them w/o a load/speakers being connected, this caused major damage to one of them and it is a case of misuse - recapped the remaining three after 10 years, or so).

4. Mac 30 mono block power amps (never a problem and recapped once approx. 20 years after manufacture).

5. Dyanco Pas3X and Dynaco Pas3 preamps (no problems - had one of them modified with the tone controls being removed from circuit - caps reformed well and were never replaced)

6. Dynaco SCA-35 integrated amp (not mine, but on long term loan - had it recapped/refurbished even though it sounded/performed fine as the caps were original and 15+ years old).

7. Audion Silver Night 300B SET amp (no problems other than the chassis ground being miswired @ the factory, per the US rep, an easy fix).

8. Pilot 690A tuner/preamp (tuner section damaged in transit, but the preamp section is fine - reformed instead of replaced original caps, no problems with this 40 year old piece).

9. Pilot 232 power amp (replaced a single ceramic resistor, otherwise no problems with this 40+ year old piece - reformed original caps).

10. Pilot 240 integrated amp (no problems - 40+ years old - reformed original caps).

11. Bottlehead Foreplay preamp kit (2+ years old - I'm the second owner - no problems).

12. Bottlehead Paramour 2a3 SET mono block kits (same info as Bottlehead Foreplay).

From my experience tubes get the nod for reliablity and I did not even list the tube guitar amps I have owned in the past (not a problem with one). I also plan to recap the old Pilot units eventually if I decide to keep/use them long term (only had them for a couple of years now).
I can't deal with them, I know they're watching me in the dark.
Nrchy -They're not watching, just glowing in your reflection :)

Thanks for all the great responses! And for letting me rant (I figure Dennis Miller is not on HBO anymore, so maybe I can take up some of the slack :-) I just wanted to say a couple more things: 1. I have absolutely no problem with those who prefer SS, for whatever reason. One of my favorite amps right now is SS (with certain speakers, other speakers I think really need tubes). 2. Guys (or gals) like Jmcgrogan2 are a blessing, in having their system strategy figured out, regardless of whether they want tubes, SS, or both, & I'm sure he already knows what he wants when he contacts sellers. 3. Handholding, or mentoring, that's a good point: I try to do as much as I can in any sale, but it's hard to do long distance via e-mail, esp. if people already have their minds made up. 4. I know tire-kickers are inevitable when selling almost anything; maybe a lot of people who e-mailed me about my amp just use the "tube hassles" excuse later on because they really weren't going to buy anyway. They're probably also e-mailing people with SS amps FS, then later bailing because they say they really want "the sound of tubes". (I'm being facetious, but it certainly wouldn't surprise me).

BTW, it looks like I have a buyer for my amp, a great guy with a great system. And in fact, he was a bit reluctant at first to buy a tube amp. But I've offered to show him how to bias it, replace the tubes, etc. (all of which I'm amazed I can even do, with my limited technical knowledge). And someday I'm gonna get those Cary mono-blocs......I just hope the tubes aren't too expensive! :-)

thanks again, steve
Its probably a lack of knowledge about tube gear.

When im able to get a good 2ch system ive been debating on going with Conrad Johnson Tube equipment, or going cheaper and buying a Krell 300i, Running some GMA Europas with either.

Im leaning more twards the Krell because i like/trust/know SS gear. I dont PREFER it because i never heard tube gear, but tubes gear looks like fun. Albeit, more maintenance is required, but im sure there is a payoff.

If i do end up getting some tube gear, i might very well opt to buy some bottlehead kits and do it that way. It would be a good learning experience and would get me into tube gear without going broke.
Seriously, tube equipment has a major advantge over solid-state. And yes, I guess it could be scarry for a novice? With SS you can only tinker so much with different interconnects where with tubes you can really tailor a entrirely different sound w/ just one swap. I guess sorta like a Turntable cartridges? DON'T BE FRIGHTENED BY THE TUBES, THEY DON'T BITE!!! Like MIKEY says, try em you might like em??? Heck you might Love Em?
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.
"Except for a few audiophiles, transistors have replaced tubes. There must be a reason"

Except for most audiophiles, 1 out of 3 still use tubes. There must be a reason. Judging by many of the above responses and in other threads, it is fear. To those that have and prefer SS, isn't it great that we have choices? And to those that HAVE experienced a cutting edge tube design, the caveats really don't matter.
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.
Solid state wears out too,I would rather own old tube gear than old solid state at least you can repair the old tube gear + it holds its value better.Output transistors need replacement after about 10-15 years or so[ask any vintage krell owner ] they degrade over time but unlike a tube amp you cant just plug in new ones.New tubes means a near fresh amp.I have gone back and forth between high quality tube and solid state gear always come back to tubes .Happy listening
Elhartford No, I wouldn't necessarily describe tube users exclusively in the audiophile camp. There are many music lovers with tube based systems that wouldn't and couldn't be categorized as audiophiles by any measure. I would have included myself in that group 10 years ago. My response was to your statement at its face value.

You make some valid comments concerning tubes in general so far as you go. It is somehow assumed by many that SS is forever reliable which is just not the case. In fact SS gear can present the owner with very costly repair costs when components fail. I would only acknowledge that tube gear in most instances requires a greater degree of maintenance to retain its maximum performance than does SS but as JohnK notes, well designed tube gear does retain its value better and is more desirable on the used market than vintage SS.

If you want to talk about reliability, great design and performance check out the Berning zh270 as a current example. Output tubes that are auto biased and cost 5.00 each to replace and will probably last 20 years. Question, which is really cheaper long term when you look at all the factors of depreciation and maintenance? In my book the only reason for purchasing a ss amp over a tube amp would be performance, definitely not maintenance. It is a negligible consideration all things considered.
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.
I have just started with tubes, I have two in my preamp stage of my integrated. Very satisfying sound. However, I do not think I would want anymore tubes than two. It does get expensive rolling. I have already spent $100+ on 3 pairs of tubes and I still want more! Also, my thoughts are you need to pay premium prices from respectable dealers if you want to recoup some of your money back if you wish to sell.
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.
Some people just will never get it.

Why don't you bring your old Stromberg Carlson over to Mr. Berning's place and have a comparative listening session. Or for that matter, bring your currently used amp over there. After you pick your jaw up off the floor, you might think of things in an entirely different way.

Or maybe you'd like to have a scientific discussion with Mr. Berning as to the technical merits of his amps. With his Doctorate Degree in Physics, 25 year history as a pioneering audio circuit designer, and his various patents of cutting edge audio circuits, he might be able to "hang with you" in the technical department, and may even be able to "struggle through" the technical reasons why his designs sound and work better than others.

I'm sure that would be a very enlightening discussion for you.
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.
Okay. I didn't say that they were for everyone.
I'm afraid of tube amps because thier glow reminds me of the alien spaceships that keep abducting me.

Twl, your not being harsh at all. You make some very good points. I'm not deaf to the charms of tubes. I've gone on record for admiring Sonic Frontier pre-amps and VTL amps. I'm very curious to hear the Berning and Wolcott stuff. These products seem to use rather unique approaches to answer the traditional tube criticisms. I have also gone on record to say that tubes are probably the better choice for higher impedance loads. I sometimes wonder if the sometimes glibb advise that occasionlly appears from time to time that suggest tubes as the pancea for all your audio woes is a catalyst for the anti-tube backlash. I can't help but believe that like most things the answer is more grey than black and white.
Slappy, I'm not going to probe that one.
Dogs are nice but getting one is a lifestyle decision. Tubes need to be viewed the same way. When I was much younger, no effort or compromise was too great in pursuit of the absolute sound. I've since receded in my dedication to that pursuit. Today many things are just too much trouble. Tubes are on that list.
Once you progress in this hobby to the point where you can be happy with what you have, then you are no longer plagued by concerns for what you may be missing. Salud!!
A little off the subject, but the spec/measurement/listening debate
has a new battle front with the new digital amps coming
to the market.

Interesting discussion of the CarverPro ZR amps over on, with J.Curl measuring these amps.

Personally, I love tubes, but I can no longer deal with
their high energy cost and heat by products. Some people enjoy the involvement of tube rolling, tweaking caps,power supplies and cables.

Every audiophile should own a tube amp at some point. Some will fall deeply in love and rediscover the joy of listening to music.
Kana813, that is an interesting discussion going on over there at audiocircle.


thats an interesting way of putting it.
My reccommendation however, is if you have a Dog do not get a tube amp.

I have a dog, a nice german shepard mix named Jagermeister, one day she started looking ill, i took her to the vet and they thought something might be obstructing her digestive track.
Got some X-Rays done and sure enough, she swallowed a lightbulb.

She ate a lightbulb. The X-ray showed it to be intact, and they had to remove it from her belly.

Not a HUGE lightbulb mind you, just a little 40-Watter, same size as what you find in lavalamps.

So.... from MY experience, If you have a dog, dont keep things that look like lightbulbs laying around the house, which includes Tubes.

Ohyeah, and dogs CAN unscrew things. They had no trouble unscrewing the cap on my waterbed. No puncture marks, no teeth marks, but they DID unscrew the cap.
lost about 10-15 gallons. Up all night long with a Rug-Docter sucking the water outta the carpet.
Got a mattress the next day.

I love dogs.

Oh and yes, i kept the lightbulb, it still worked. :)
"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"

Elhartford, first hand I wouldn't know but it is my understanding that David Berning was using one of his amps with Maggies and I have heard from others that it works quite well although it wouldn't seem so. You are quoting the spec for the low feedback setting, you would probably have to use the normal setting with Maggies.

I suppose if specs were the be all end all of what we hear, most well healed audiophiles would own Halcro amps, they don't and some suggest it has a "sterile" sound. Reminds me of the 30K Denon amps from 10 years back or so that I heard, extremely wide bandwidth with ultra low distortion specs which is how it was marketed. Bottom line is I hold very little value in specifications when listening, the design, application and end result is what really matters. While it is quite easy to hear the 2nd order harmonic distortions in many tube amps, there are other designs where this is less apparent. Tube amps definitely have their limitations in many applications without getting into the humongous beasts that require huge transformers, many tubes and costly maintenance but a viable choice for those that have difficult loads that would pass on SS.

I'm not knocking ss, I haven't heard them all and it is evident that they are improving and if they provide the magic of the illusion to those that listen, bravo, that is all that matters. I would love to hear a ss amp based system that provides the magic I have experienced from some of the great tube systems I have heard, I haven't to date, just good sound.

And Slappy, when you finally get around to tubes, which I am confident you will, just make sure it has a cover to keep that mischevous dog from temptation.
Kana & Twl: can you post a link to the threads on Audiocircle that you are referring to ?

El: tubes are VERY much alive in high powered RF and in the music industry. Just ask a "rockin" guitar player. Sure, some of them use SS amps, but a huge portion still cling to and are drawn to the sound of a Marshall, Ampeg, Hi-Watt, Orange, Fender, Mesa-Boogie, etc.. tube head. Even some of the Peavey amps use tubes to great effect to obtain their specific gain characteristics and tonality.

Tubegroover: Low distortion can be achieved two ways. One is to build a very simple yet well designed wide-bandwidth circuit that is relatively stable into the intended type of load that will be used with it. This can be relatively costly as it is harder to keep a simpler circuit stable into various loads and do so while retaining wide-bandwidth. As such, it may require a lot of R&D prior to arriving at a suitable design.

The other method that is FAR more common is to build a pretty decent circuit and then try to correct any deficiencies in linearity with gobs of negative feedback.

The second method is a LOT cheaper than the first to build, design and market. As one might surmise, the cheaper one almost always sounds worse but is more stable over-all, hence the use of such approach by most mass production manufacturers. I think that Halcro tried to combine both approaches but probably used too much negative feedback in order to obtain phenomenally good measurements in specific areas. One could probably add a great deal of "musicality" to the Halcro by changing a few caps, etc.. internally. Just a guess though.

As a side note, I find that i like a lot of Nelson Pass' designed amps. The funny thing here is that they don't have "killer specs" in any specific area*. The distortion is surely not "ultra-low" nor are they phenomenally "fast" in terms of rise time or slew rate. As such, i think that Nelson tried to achieve the best of both worlds i.e. some of the more desirable sonic attributes of tubes with the better measurements and bass impact of SS. From what i can tell by the specs, he seems to have found a compromise between the two. The specs appear to fall somewhere between the two different types of products i.e. lower distortions and faster response than most tube circuits but higher distortions and slower responses than the "best" ( in terms of specs ) SS amps. Has anybody else ever taken note of this or shared these thoughts ? Sean

* Other than price : )
Sean- here you go:
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?
What is boils down to is $$. I've auditioned over 100 SS and tube amps combine. There are plenty of good solid state amps that performs as good as some of the best tube amps. However, the price for the SS are always outrageously higher than the equal performance tube gear.
i.e. If I need SS 100Watt power amp that can be better than a HK Citation II, I'll need to spend at least over $2000 in SS amp to achieve to same sonic performance.
Anything less just doesn't cut it.
The cost of a vintage HK Citation II is only arond $800. In the silimar price range SS amp, thin, dull, dry and flat sounding SS amp are not my cup of tea. It just doesn't have the same bandwidth as the tube gear.
However, if you're talking about current production tube amp, the price tag is much closer these days ( the manufacture jack up the price on tube gear since it is "HOT". In any case, I still prefer vintage tube gear.

Just my 2 cents
Sean, here's the link to the audiocircle discussion on the digital amps.

There's about 9 pages of discussion on the apparent poor measurements and good sound reports from it. John Curl and Brian Cheney are involved.
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.
I agree. They are a long way from tubes. Just providing the link that Sean requested.
Thank you very much for posting that Twl. I have some comments that i'd like to add to that thread, but have to run off to work. Some of my comments are both pro and con about this type of amp and other Carver / Sunfire products. Being an owner of multiple Sunfire products might help keep the negative things that i have to say in perspective for those that are otherwise "awed" by the sound of this amp even though it measures attrociously. Sean

PS... I have to wonder just how much of this really is Carver and / or if Bob is simply marketing his name ??? You guys check into that and let me know, will ya ??? : )
Correct me if I'm wrong, but, isn't the TacT really the best example (not best amp, but, best example) of a digital amp.