Originally Posted by
2obed 
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Originally Posted by
2tvsonecup
As far as DACs are concerned - I have not listened to new cheap built in DACs. Perhaps they have become superb. The DAC built in to my HK3490 is no worse than my aging CPDs, it also is no better. All of them are better than the DAC built into a iPod touch (2nd gen, I think) which created a haze to my ears. My kids lived with it happily, they hardly heard it. I trust my kids' opinion that it was not important to them. But for me it was a reality I could not accept in audio reproduction. I could happily live with the DAC in a 30 G iPod of whatever generation. Apparently it was a different DAC - a better DAC for an iPod that was intended primarily for music. I guess the Apple designers decided that there was a difference to the sound. Or perhaps it was just a marketing decisions - though I doubt very much that the average iPod buyer would have heard of Wolfson or Burr-Brown, and TI would mean a calculator
I now use a relatively cheap outboard DAC ($200) / preamp. To my ears it has improved the depth and width of the soundstage, and cleared up a bit of the haze. (As a bonus, the preamp section was better than the HK pre-amp, so I am bypassing the HK pre-amp and use the HK as a power amp.)
One of the problems with subjective technology is that it is sometimes hard to figure out what is actually meant.
A comparison between an iPod and a home stereo is particularly difficult because unless the listening evaluation is set up right, I can guarantee an audible difference ever if we were comparing two identical iPods. What I'm referrring to is the fact that iPods are usually listened to with earphones or headphones, while receivers and CD players are usually listened to with loudspeakers. That is a huge difference due to the use of such different ways for listening. In general headphones let you hear far more of the detail and the built-in acoustics of the source recording because there is no room to smear the music by adding its own acoustics.
So, lets say that to make this more of an apples-to-apples comparison by hooking the iPod up to the AVR and using the speakers to listen to for both devices. The next big difference will be that unless you do a very careful setup with test recordings and test equipment, the listening levels will be different. Even small differences in listening levels sounds different. Some will tell you that louder always sounds better but I know from experience that is not a true statement for all possible listening levels. However, it is a true statement that different listening levels will sound different and when presented with the same music played at different listening levels you may or may not perceive the difference to be just louder or softer. There will also be changes in timbre, imaging, and inner detail and even haze. Once you get the levels matched closely enough (which can't be done reliably with a SPL meter) there are still other issues that need to be handled.
One of the true and sometimes tough tests of a listening evaluation is that it will produce an outcome of "no differences" when there are actually no differences. This may seem trivial but it is not in actual practice.
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If you cannot hear the difference between SS and Tube gear, it would be logical to pick the SS gear for its ease of use. No tubes will blow, taking caps with them to audio heaven. Power tubes last about 3000 - 5000 hours before they begin to degrade. It does cost money to replace them. You get a lot more WPC for your buck with SS. SS tends to control bass better than tubes. SS is less sensitive to impedance curves. SS will probably produce less heat in this price range than even an class A/B tube amp. You need a lot more space above a tube amp than above a SS amp for ventilation.
All true. One of the ironies of audiophilia is that back in the days when tubes were all we had, there was a more-or-less tacit agreement to try to build tube amps so that they had as little coloration as possible and therefore sounded as much alike as possible. In recent times a goodly portion of the tubed amplifer business is devoted to equipment that to an old-timer like me looks like it is as badly engineered as possible. For example since it was invented in the early 1930s, push-pull operation has been a leading technology for making tubed amps sound as good and uncolored as possible. So, what has tube-audiophilia brought back but SET amplifiers that are not only not push-pull but also have avoided many other technical refinements that helps tube amplifiers sound as good and transparent as possible.
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I am not sure that tubes are not for beginners. Tubes are what our parents and grandparents grew up with. They did not have the option to progress to tubes from solid state. Most of them lived long enough to reproduce despite the onerousness of tube equipment, Today's entry level tube equipment tends to be auto bias, other than replacing tubes there is little that needs doing. I do watch my tubes when I turn on the amp - just in case. Tube equipment is more prone to hum because of the big transformers - but with a bit of care mine are dead quiet through the speakers. The transformers on my 300B have a physical hum that I can hear from 2 1/2 feet (when there is no music playing.)
The suggestion that tube equipment works like a tone control on SS gear is not consistent with my experience.
One difference being that tone controls are adjustable by the end user while the tonal variations that modern tubed amps add to the music are not easily controlled by anybody. They are largely determined by the impedance curve of the speakers that you use with them.
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I do think that there appears to be some inconsistency in believing in measurements (Tube equipment tends to measure quite flat over an extended frequency range)
That is incorrect. Tubed amps are especially prone to having non-flat frequency response due to the technical problems of output transformers.
Consider the following test results for a tubed power amp based on 300B tubes::
versus this SS amplfiier (Bryston 7B);
Notice that the vertical dB scale is greatly expanded in the second chart, magnifying the appearance of non-flat frequency response. Its vertical scale is about 4x that of the upper chart, so the same amount of wiggling around represents 4 times
smaller actual variations! I would say that it has about 8 times flatter frequency response which in this case means that the tubed amp is probably audibly non-flat and colors the music while the SS amp is probably completely free of audible coloration.
