wipster Posted July 9, 2011 Share Posted July 9, 2011 While we were moving things around to properly place the the Heresy's, we decided to do a blind A/B comparison between the two speaker pairs. I had a spare speaker switch (I save everything... I think I have the first patch cord I ever bought), so we were able to easily switch between the speakers without the listener knowing which speakers they were listening to. While both speaker pairs sounded great, it was obvious to the three of the people listening (all Klipschoholics) that the Heresy's clearly sounded the best of the two with vinyl and the Fortes clearly sounded the best with CD’s and digital feeds, all with the same amplification (the tube system)... almost like they were designed that way and maybe they were? I know when I first heard the Fortes, a CD was used, and obviously an LP was spinning when I first heard my Heresy's. Even though we were using tube amplication for this test, I would bet money that the Heresy's sound better using tubes and the Fortes would sound the better of the two using solid state (note I did not say they would sound better using solid state because when I was using the Fortes both both amps, they sounded better using the Eico's as well, even though the Onkyo is a great sounding SS amp). Thought I would share, as this experiment was a lot of fun, with some definite conclusions about heritage speakers and analog v SS at least. The only flaw in the experiment that you outlined is that you didn't state whether you level matched when switching between speakers. Without that, it's almost impossible to draw definite conclusions. We considered if level matching would be necessary, but honestly there was not enough difference between the efficiency of the Fortes (98 dB) and the Heresy's (96 dB) to make a difference, at least one that we could distinguish. At very high levels you could discern a slight difference in volume, but that's not why we were comparing the speakers... we wanted to see how different the tonal quality was, and it was a learning experience, as there was more than we anticipated. If I were doing a blind A/B comparison for Stereophile, I'm sure I would have all the proper equipment to perform proper level matching; however, we were just three guys having fun and we more than accomplished our goal, flaws and all. Quote Link to comment Share on other sites More sharing options...
jhoak Posted July 10, 2011 Share Posted July 10, 2011 Here's an interesting article on the subject of "tubes" that I received today by way of the TubeStore newsletter. http://electronicdesign.com/Blogs/Communique/tabid/731/entryid/170/Default.aspx Quote Link to comment Share on other sites More sharing options...
Chris A Posted July 10, 2011 Share Posted July 10, 2011 Could someone explain to me why tubes sound so much better, especially with Klipsch speakers, that audiophiles are willing to spend more money and time to obtain even a used set. I think that best source on that subject that I have seen is an interview with Bob Carver of Sunfire, Carver, and Phase Linear fame. The funny thing is, what he says is that the high output impedance of tube amplifiers actually cause the speaker/power amplifier loop to reverberate based on room acoustics - thus adding a (artificial) sense of spaciousness to the listening experience. It's actually very interesting - and explains a lot to me. It also explains why so many tube fanatics usually have small listening rooms (at least to me). The smaller the room, the better the effect since the room's first reflection SPLs fall off something approaching the square of the distance to the reflecting point. Also note that any disturbances in the input impedance curve of the speaker will tend to interact with the amplifier in a non-linear way. Here is a link to a paper on the Khorn's input impedance. You can see that what the real effect is isn't "linear". I'd say that the tube amps are actually serving as a reverb unit that sounds like added spaciousness, and also acting as an EQ unit. Carver is the guy that designed and marketed the "Silver Seven" tube amplifiers of $$$$ fame, among many other things (including the first really high power/low cost SS amps) - and also met and exceeded the Stereophile challenge to duplicate high dollar Conrad-Johnson Premier Five tube amp performance with low cost SS gear (I still own a copy of his amp that passed another test to duplicate a Mark Levinson ML-2 SS amp.) [8-|][][] Chris Quote Link to comment Share on other sites More sharing options...
WMcD Posted July 10, 2011 Share Posted July 10, 2011 I'll have to read that article. I suppose there could be something going on with horn speakers being sort of good microphones which feed room sounds back into the amp -- but it seems far fetched. It would be interesting to put a K-Horn in one room and wire it to a K-Horn in a distant room or garage. Then hear how much they act as self powered telephones. "Come here Watson, I need you." One starting point of mine is that notion that all accurate amps sound the same. That is not to say that all amps sound the same. Quad pretty much showed that the input and output of their amps were indistinguishable except for level. So there are accurate amps. (At least at high power -- see below.) But do accurate amps sound good? And do accurate speakers sound good? Maybe not. It is pretty well accepted that even order (?) harmonic distortion sounds warm and musical. Probably K-Horns are so accurate that this type of distortion is lacking. A cure might be to use an amp which has more of the favorable distortion. There are other issues with damping. The horns create a damped condition for the driver. PWK favored autotransformers in the crossover to maintain electrical damping (low drive impedance). Yet in a footnote to one of his articles, he later said it is not necessary. A final issue regarding amps and maybe even capacitors and inductors is performance at low levels. We're getting 104 dB at 1 watt or 2.82 volts (nominal). In some classical music I'll say we're listening to nuances at 44 dB which is 60 dB down from that peak. Pretty much near the noise floor of a room, but it is there. I'll ask Dr. Who and others here to check my numbers -- they are astonishing. But in my calculations, that the 44 dB (60 dB below 1 watt) number results in the amp putting out 1 microwatt. Yes, one-one-millionth of a watt. Into a nominal 8 ohm load that is 2.828 millivolts. It really does give one pause. If you go into a theoretical store to buy an amp for a K-Horn you will be shown amps putting out 10 watts or 100 watts with some distortion measured at full power. What you should ask for is the amp's distortion level at 1 microwatt or at levels somewhat above. Are tube amps or SS amps good or bad at this level? Comments? WMcD. Quote Link to comment Share on other sites More sharing options...
gnatnoop Posted July 10, 2011 Share Posted July 10, 2011 Thanks Tube Fanatic. Your explanation is very helpful. I'll check out the companies you mentioned. Tube Fanatic covered it much better than i could have. [Y] I'd only add that you need not match brands on pre's and power amps. Quote Link to comment Share on other sites More sharing options...
Chris A Posted July 12, 2011 Share Posted July 12, 2011 Good to see you out of the "hole", Mr. Deneen ...[] I always enjoy reading your opinions, especially in this subject area... Chris Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted July 15, 2011 Share Posted July 15, 2011 Tubes and SS can both sound good with Klipsch speakers. Quote Link to comment Share on other sites More sharing options...
Don Richard Posted July 15, 2011 Share Posted July 15, 2011 Here is part of a recent thread in the Technical section that helps explain some differences: http://community.klipsch.com/forums/t/150977.aspx?PageIndex=2 Quote Link to comment Share on other sites More sharing options...
gagelle Posted July 17, 2011 Author Share Posted July 17, 2011 Dave: I recognize some of the best and most collectible vintage units ever made. Absolutely beautiful! Quote Link to comment Share on other sites More sharing options...
gagelle Posted July 17, 2011 Author Share Posted July 17, 2011 Tube Fanatic: I never imagined that my question would lead to so many responses and points of view. I appreciate them all but don't have the time to answer everyone. Your explanation stands out for some reason. Perhaps because it seems more balanced and objective. I've been doing some research in my spare time and I've found several very nice tube amplifiers that are new. They are low powered, like five or six watts. The ones that are close to 18 watts are double the price which is already high. Then one has to add in the cost of a preamp which sometimes is as much as the amp itself. Then there's the cost of a tube preamp for records which may not be part of the regular preamp. In all fairness, some of the amps have one input but sometimes lack a volume control. So I may have to spend close to $3,000 for a 5 watt setup which may or may not sound good. When I read different reviews, it leads to more confusion. One person thinks the five watt unit sounds great. Another swears they have to be used as monoblocks to get a good sound stage. The used equipment is even more confusing. The popular vintage units cost a fortune and often need to be refurbushed. They need bias adjustments and the really old ones may not work with modern electric current.. I exclude the cheap Chinese amps, but I have no knowledge of these either. But my impression is that a good tube setup is expensive. One statement that you made makes the most sense: I have to listen to one myself. Unfortunately, I have to drive several hours to get to an area that has a showroom with tube amps. But this whole exploration lead me to one good thing. I found a cheap "learn to solder" kit complete with a small circuit board. It's made by Carl's electronics, which sells various tube kits that are much less expensive than completed units. In any case, I thank you and everyone else for all the valuable information. Quote Link to comment Share on other sites More sharing options...
gagelle Posted July 18, 2011 Author Share Posted July 18, 2011 Another thing that I noticed with the vintage tube amps on eBay: some of them have no cover. So I go look at reviews and find out there are lethal amounts of electricity flowing through sections of the chassis. The company added a cover the following year. That would go over well with my cats-returning home to baked cat. Quote Link to comment Share on other sites More sharing options...
Don Richard Posted July 18, 2011 Share Posted July 18, 2011 You would have to have a tube like a 6146 with an uninsulated top-of-tube plate connector for any lethal voltage to be exposed on top of the chassis. There are not many, if any, hifi amplifiers using that tube. Power tubes do run rather hot, so the cover is there to prevent burns from accidental touching. The bottom cover should always be installed on an amplifier that uses high voltage power supplies for safety's sake, or on any sort of amplifier to keep out dust, insects, etc. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted July 18, 2011 Share Posted July 18, 2011 Another thing that I noticed with the vintage tube amps on eBay: some of them have no cover. So I go look at reviews and find out there are lethal amounts of electricity flowing through sections of the chassis. The company added a cover the following year. That would go over well with my cats-returning home to baked cat. Cabinets/covers for many 50s and 60s amps were an optional purchase since many users installed the amps in custom enclosures, book cases, etc. Since the cabinets were often costly (by the standards of the times), I always felt that the manufacturers were being considerate in not forcing consumers to purchase what they didn't need. Another advantage to having an exposed chassis and tubes is the greatly improved ventilation which translates into longer tube life (especially in designs which ran the tubes at or even above their design maximum ratings). Quote Link to comment Share on other sites More sharing options...
Chris A Posted July 18, 2011 Share Posted July 18, 2011 Quote Link to comment Share on other sites More sharing options...
gagelle Posted July 19, 2011 Author Share Posted July 19, 2011 Perhaps one day if I get the money. I already have a collection of equipment I'm not using. I'm also surprised at some of the prices that anything with tubes in it is going for on Ebay. Even low end units that sold for $150 a few years ago are selling for over $300 now. There seems to be a "tube mania" going on. I don't know if these buyers realize that you can't just "turn on" an amp made in 1959 without a thorough professional evaluation. Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted July 19, 2011 Share Posted July 19, 2011 Most of the discussion pretty much hits the nail on the head so to speak... Different physics yield different sound (good and bad) Tubes can be manipulated (rolled) to induce subtle and sometimes very desirable differences that are very difficult to duplicate with solid state. To forgego tubes in favor of solid state requires the ss amp to be generally of a high quality, and like tubes, may require a number of different amps to find the "right one". It's all in the ears of the listener..... [H] Quote Link to comment Share on other sites More sharing options...
Boxx Posted July 21, 2011 Share Posted July 21, 2011 I don't know if these buyers realize that you can't just "turn on" an amp made in 1959 without a thorough professional evaluation. It is great to be able to thoroughly restore vintage gear before using, but very few Ebay buyers do that. Most roll the dice. This is so true and more often than not results in very unsatisfactory results following a transaction (ie. poor feedback, claims, etc...) Quote Link to comment Share on other sites More sharing options...
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