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Post by Boomzilla on Jun 9, 2013 9:31:30 GMT -5
Mr. Carver's fortuitous addition to the Jade Design Group hopefully portends great things to come. The current leaders in the area of vacuum tube preamplifiers, Audio Research and Conrad Johnson, produce wonderful products, although at awesome prices (and the adjective "awesome" is here used in its traditional meaning - "inspiring of awe"). Hopefully, the Chinese manufacturing and internet-direct sales model of Jade will be able to result in equivalent or better products at more affordable prices. As to the product lineup, KeithL has already implied that the first product may be an "entry level" preamplifier. A separate thread has proliferated with multiple requests for inclusion / exclusion of specific features. I won't drag all of that into this area, but the interest is obviously high. After the initial preamp succeeds, I'm far more interested in the follow-up products - perhaps a state of the art (SOTA) preamplifier with an intermediate-level product as well. So for the moment, I'd like to speculate on just what a SOTA tube preamp might include, here at the beginning of the 21st century. Because home theater and stereo listening are becoming so integrated in the vast majority of homes, I'm wondering if a "hybrid" preamp that offers elements of both types of systems would be appropriate. Features that might be included in such a preamp would be very diverse: - USB, TOSLINK, digital RCA, and HDMI audio inputs (notice that I specifically omitted mention of video inputs, which should NOT be part of any tubed preamp)
- D-A Converter (with software upgradable ROM) for not only stereo but also all current multi-channel surround sound formats
- Bass management and room correction (with software upgradable ROM) in the digital domain (prior to D-A conversion)
- Some adjustable version of "sonic holography" for stereo-only listening - If the concept is good enough for the hoity-toity reviewers to put on their recommended list vis-a-vis the BSG Technologies QOL "Signal Completion Device," it's good enough for a SOTA preamp
- XLR inputs and outputs
- Optional phono stage
- Optional unbalanced inputs/outputs
- Output buffer to drive long interconnects and low-impedance amplifier inputs
- Electric-fence-style shocker to dissuade tube rollers
I'm sure that Lonnie & Mr. Carver have their own ideas, but the above are my humble suggestions. In any case, I'd be interested in other Lounge denizens' thoughts on what a SOTA tube preamp might need or not. Cordially - Boomzilla |
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DYohn
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Post by DYohn on Jun 9, 2013 9:35:42 GMT -5
I say get rid of the digital inputs. Analog only, please. And why would you want to dissuade tube rolling when that is one of the joys of owning tube-based gear?
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Post by Boomzilla on Jun 9, 2013 9:37:05 GMT -5
I say get rid of the digital inputs. Analog only, please. And why would you want to dissuade tube rolling when that is one of the joys of owning tube-based gear? I'm a male curmudgeon, thanks...  |
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Post by mgbpuff on Jun 9, 2013 9:57:00 GMT -5
Keep all digital crap out of it. Analog only including any bass management it may have. Holographic circuits welcome provided they are analog in nature. Buy outboard RMC,DACs,or digital bass management if that is your desire. By all means allow tube rolling. Make it differential fully balanced inside and out with single ended and XLR multiple connections. See a Cary SLP-03 for the kind of analog flexibility without digital encroachment that it should emulate. In fact the Cary is flexible and affordable, so the new Emotiva would have to beat it and be even more affordable. A phono input would elevate it above the Cary in features.
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Post by jlafrenz on Jun 9, 2013 10:18:51 GMT -5
I say get rid of the digital inputs. Analog only, please. And why would you want to dissuade tube rolling when that is one of the joys of owning tube-based gear? Agree |
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Post by Chuck Elliot on Jun 9, 2013 10:54:18 GMT -5
I say get rid of the digital inputs. Analog only, please. And why would you want to dissuade tube rolling when that is one of the joys of owning tube-based gear? +1 But a separate tube DAC with a tube stage I/V* and not just a cathode follower(buffer) would also be a nice addition too. *Most DAC chips output current which needs to be converted to voltage.  |
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Post by AudioHTIT on Jun 9, 2013 11:36:05 GMT -5
I'm a male curmudgeon, thanks... Is there any other kind? |
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Post by Boomzilla on Jun 9, 2013 12:25:16 GMT -5
I'm a male curmudgeon, thanks... Is there any other kind? You haven't met my wife? LOL |
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Post by Boomzilla on Jun 9, 2013 12:40:01 GMT -5
I say get rid of the digital inputs. Analog only, please. And why would you want to dissuade tube rolling when that is one of the joys of owning tube-based gear? Keep all digital crap out of it... But a separate tube DAC with a tube stage... Youse guys are so 20th century! Nevertheless, I'm sure Lonnie & Mr. Carver hear ya... I'm just hoping that they also have the market savvy to look beyond all of us "grouchy, male audiophiles" as we're called and consider the future. Aint a kid on the block that much cares about analog, but they'll hear the difference with tubes - particularly affordable tubes. That'll happen if and only if they need not listen with the atrocious DACs in their iGear. For that reason, I think that any "high end" preamp absolutely MUST contain good DACs. |
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Post by jlafrenz on Jun 9, 2013 13:07:09 GMT -5
I think those who listen to the type of devices you describe and want convenience for them are not the same market as those who are buying tube gear.
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DYohn
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Post by DYohn on Jun 9, 2013 13:26:49 GMT -5
Agree. People who are interested in tubes for more than the pretty glow want amazing sounding analog line stages. Period. When I need a DAC I'll use one, and I want the flexibility to use the one I like. Don't put one in my 2-channel preamp, thanks. |
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Post by Boomzilla on Jun 9, 2013 14:30:35 GMT -5
I understand what you're saying. We'll just agree to disagree on this one. I suspect that your preferences rather than mine will win out in the end.
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Post by arthurz on Jun 9, 2013 16:54:13 GMT -5
I agree about not including a DAC, but I really wish someone made a preamp that is able to communicate with a multi-input DAC to switch a number of virtual inputs using the preamp's remote. What I mean is that you could have a computer, an Airport Express, and an Apple TV connected to the DAC, the DAC connected to the pre-amp using one set of cables, but then the three DAC inputs would be managed as three separate inputs to the preamp.
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Post by mgbpuff on Jun 9, 2013 17:02:33 GMT -5
Why not use the DAC remote? The XDA-1 has input selection, for instance!
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Post by arthurz on Jun 9, 2013 17:25:01 GMT -5
That would be perfectly fine if all your inputs were on the DAC, but that's not the case, so you have to choose the right combination of inputs on TWO remotes before you get what you want. As they say in Argentina, that's retarded.
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Post by jlafrenz on Jun 9, 2013 18:35:35 GMT -5
I agree about not including a DAC, but I really wish someone made a preamp that is able to communicate with a multi-input DAC to switch a number of virtual inputs using the preamp's remote. What I mean is that you could have a computer, an Airport Express, and an Apple TV connected to the DAC, the DAC connected to the pre-amp using one set of cables, but then the three DAC inputs would be managed as three separate inputs to the preamp. If all your sources are connected to the DAC and you have one set of cables running to the preamp, you would only need to switch the source in one place. You would just leave the input on the preamp as it is. This is assuming that you don't have other sources not running through the DAC such as a turntable. If this were the case, then you would only have to switch the input on the preamp and leave the DAC source selection alone. |
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Post by arthurz on Jun 9, 2013 19:33:06 GMT -5
I understand this . Not all my sources are connected to the DAC. If one is willing to embrace complexity, today's arrangement works perfectly fine, just like MS Windows. I am a Mac user... |
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Post by mgbpuff on Jun 9, 2013 20:00:55 GMT -5
Program a universal to do it. I have an iTouch with a NewKinetix IR sensor and software that would allow you to program a sequence of commands from a simple screen prompt such as 'listen to computer music' or 'watch Apple TV' or "listen to Airport Express".
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Post by arthurz on Jun 9, 2013 20:09:21 GMT -5
I've implemented an even simpler solution – I have one XDA-2 per source and use the XSP-1 to switch them . (The real reason for this is that my AV7701 can only use analog sources for zones 2 and 3, but I still really appreciate how this setup simplifies my life in zone 1.) |
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KeithL
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Post by KeithL on Jun 9, 2013 20:29:12 GMT -5
What you've shown is *not* a tube-based I/V stage. It is a passive I/V stage (the two 60 ohm resistors to ground) followed by a high gain differential tube preamp. The optimum output termination for a current-output DAC is a current-to-voltage converter input at virtual ground potential. Typically, this is achieved by connecting the current output(s) to the inverting input of an op-amp (or a pair of op-amps for differential) connected in an inverting configuration. The current output "sees" a virtual ground, and the op-amp output is a voltage that is directly proportional to this input current. The 60 ohm resistors in this circuit are a rather severe compromise on that goal - the voltage they generate from the current outputs of the DACs will be very low, which will result in an overall signal-to-noise ratio comparable to a decent tube phono preamp (which is far inferior to even a mediocre DAC). Since they are not really at virtual ground potential, they will also introduce offsets and other problems which will have to be addressed as well. As a "proof of concept" for "using more tubes" the circuit is interesting, but, if you want to get the best audio quality from a DAC, yet impart some "tube sound" (the characteristic coloration added by tube amplification circuits) to the results, it makes much more sense to do the I/V conversion optimally (with a solid state I/V stage), and then add a tube buffer to the output. I say get rid of the digital inputs. Analog only, please. And why would you want to dissuade tube rolling when that is one of the joys of owning tube-based gear? +1 But a separate tube DAC with a tube stage I/V* and not just a cathode follower(buffer) would also be a nice addition too. *Most DAC chips output current which needs to be converted to voltage. |
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