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In Reply to: RE: Why so few Tube Dacs? posted by Dynobot on July 14, 2012 at 18:11:38
These normally take the digital output and convert the signal into an analog line-level output that can then be fed into an amplifier to drive speakers. Why does a device that converts a digital code to an analog signal need a tube?
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The Driver smiled when he lost the car in pursuit...
Follow Ups:
Why do you feel the need to add a meaningless graphic to every post you make? It serves no purpose and for the folks on slow connection it is a royal pain in the ass....Wake up, dummy.
-RW-
-RW-
I am sorry that you do not understand the need to have adequate Ram on your machine. I get the feeling that a lot of the Audio things being addressed here including but not limited to audio players, dac's, pre-amps, connections, amplifiers and even speakers. Are patches to try to bring antiquated, devices up to what is possible today. If your priorities are in order, keeping a state of the art computer will save you more time per dollar, than patching up any old audio only system. When someone in the future searches to find the answers in the data base we are laying down here, we would all be fools to optimize for the past centuries dial-up, instead of the normal speeds that has been available for the last decade.The thousand words in this picture shows a corner that could be taken slow, but you might choose to accelerate and have some fun when you are confident and driving a Porscha. You go slow because you want to go slow, that is your life, your choice. That is not a valid reason to hold everybody else back.
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The Driver smiled when he lost the car in pursuit taking the S turn at speed...
Edits: 07/24/12 07/25/12
> > The thousand words in this picture shows a corner that could be taken slow, but you might choose to accelerate and have some fun when you are confident and driving a Porscha. You go slow because you want to go slow, that is your life, your choice. That is not a valid reason to hold everybody else back. < <
Actually, going DEAD SLOW around such dangerous corners is a required safety issue for both you, oncoming traffic, or kids, pedestrians and/or animals that cannot be seen otherwise.
Your example of "fun" in this particular case could kill someone.
tb1
I used to enjoy driving fast. (Won't say how fast...) After living in Vermont for almost 20 years I've seen two fatal accidents caused by cars hitting moose and had a few close calls myself. One of the fatal accidents on an Interstate highway involved a car in front of me that hit a moose. The driver was going slowly and I was a few seconds from making the decision to pass her when the accident occurred and I ended up driving through the debris field. Just last week I would have hit a small doe and tiny faun if I had been speeding down a steep hill, but fortunately I was going the 40 MPH limit.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
The output of DAC chips is small. Amplification is therefore a required function of a DAC, which must drive a line level signal. Using a vacuum tube is only one possible mechanism to achieve the amplification. One needs some amplification, but it doesn't have to come from a tube.
Some people want the noise and distortion of tubes, although this isn't the terminology that they use to describe the coloration of sound. Perhaps the noise and distortion are covering or cancelling some defect in their recordings or playback chain. One problem with many systems is that their high frequency response on axis is too flat, making many recordings excessively bright. Tubes have a higher output impedance than solid state line drivers and this combines with the capacitance of interconnect cables to provide high frequency roll-off. It is one of the inane aspects of "high end" audio that some people result to extremely expensive means to accomplish something that used to be accomplished inexpensively (e.g. with a tone control).
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
nothing to do with it. It's not the high frequencies that matter it's the midrange, Midrange, Midrange! That is where vacuum tube circuits sound more real and life-like, especially with vocal material, than solid state circuits ever seem able to pull off. After all, we’re not trying to trick an oscilloscope we’re trying to trick the human ear / brain auditory neural system into believing that a recording is instead a real live sound. It's all a magic act and thermionic emitters perform the prestidigitation with more finesse than a hunk of silicon.
> > It's not the high frequencies that matter it's the midrange, Midrange, Midrange! < <
the only way for me to have a pseudo realistic image of an audio live event within the confines of any living space via any "stereo" is totally equal to how the system reproduces the frequency extremes, not simply how it reproduces the midrange. The fact is, systems that do not properly reproduce the extremes, won't reproduce the midrange properly either.
> > That is where vacuum tube circuits sound more real and life-like, especially with vocal material, than solid state circuits ever seem able to pull off. < <
Just another myth easily proven wrong by reality!
tb1
This confirms my experience. When I applied corrective room EQ DSP in my computer playback I expected the bass to be smoother as I cancelled three room modes that had 6 - 10 dB peaks. What I didn't realize was how the sound stage improved, even when listening to portions of an orchestral performance that hadn't been obviously exercising the room modes.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
> > What I didn't realize was how the sound stage improved, < <
I've heard far too many systems that supposedly had a "great" midrange ... but to my ears, couldn't throw out a proper 3 dimensional soundstage because the extreme frequencies were either absent and/or phasey.
Although an entire system is responsible, far too many source components fail to deliver the freq. extremes in proper fashion. It took several decades for CD players to reproduce the highs properly, and most analog units still produce phase issues with the highs.
The bottom line with audio reproduction, you simply can't have a "great" midrange without proper freq. extremes, despite what some tube fanatics claim.
tb1
Ideally, the DAC should produce the same output as the ADC received as input. If that input is "magic", then the output will be equally "magic". If your DAC changes the sound then you will miss out on the really magic recordings.
If you haven't made recordings then I would not expect you to understand the issues involved.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
lifelike than even today's high resolution digital does. And, I didn't say it was magic I said it's like a magic trick, the whole point is to fool the auditory sense into believing something that is not real.
The best records from the golden age of stereo recording in the 50s were all done on tube gear. That is not to say that a quality recording could not be made today but unfortunately there is no economic incentive to do so. Also, when one starts with forty channel multi-track mixers and digital compressors the temptation to do ill is apparently too great and sound quality goes south in a hurry as over 90% of the current media market painfully demonstrates. Thank you, Theodore Sturgeon.
Lastly, all the solid state proponents disdain for vacuum tubes does not seem to have adversely affected Audio Note and Jadis sales any or for that matter the thirty other companies I listed that sell vacuum tube DACs. Plus, the fact that here we are in the second decade of the 21st century and vacuum tubes are still being made; if you had told someone that back in the 1970s they would never have believed it.
I have many of these "best" recordings and they have been sonically surpassed by modern high resolution digital recordings, including those made by Reference Recordings (176/24), Water Lily Acoustics (dsd64) and Channel Classics (dsd64). Alas, the musicians (long dead) have not been surpassed.
The problem with the classic recordings is the poor S/N ratio of the tape, and/or the saturation distortion which resulted when engineers such as Lewis Layton attempted to compensate by boosting the levels. It was always easy to hear a difference between a live microphone feed and a 15 IPS tape playback of the same recording, whether solo music or the Boston Symphony Orchestra.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
case of a current out DAC the output must go through a current to voltage conversion I/V, typically an opamp circuit. In the case of a voltage out DAC the signal still requires a buffer stage as a DAC chip cannot drive the line out directly, no power to speak of. Think of it like moving coil cartridges require a step-up and phono stage before a line level output is achieved. Actually, all DACs are current out in the case of voltage out DAC chips they simply have the I/V conversion built into the chip. In the case of commercial CD or DVD players they may have five stages or more of opamps in-between the output of the DAC chip itself and the actual RCA jack output. Those opamp circuits could be replaced with discrete transistors or in this case vacuum tubes. In the case of current out DAC chips a transformer is used for the I/V conversion and then a vacuum tube stage is used to amplify the resulting signal to a usable line level output.
nt
... Keynes, Galbraith, Samuelson, Shiller, Reich, Stiglitz, Krugman, Singh
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