Originally Posted by SteveCallas Hold on just one minute
The purpose and goals of our test were clearly stated in post 1, sound quality based on DACs and analog prestage. This is what Jon and I wanted to test, as we are both using discrete amplification (with beefy amps) and neither of us needs much more inputs/outputs then what a common unit provides.
If you are trying to compare DACs and analog prestages, would it not be of some value to have researched (and posted) exactly what parts are performing these functions? If it happened that all of you test gear contained the very same parts, then what value would your test have then? One would think Science 101 would include at least this much basic info, lest this be considered pseudo science instead.
For example: If I were comparing (and I currently am) the Anthem AVM-50 to the Anthem D2, I would note that the AVM-50 uses AKM AK4382 converters on the DAC versus the D2 using the AKM AK4395 parts. I would also note that the both do upsample D to A up to 24-bit/192kHz and maybe even that the D2 uses two Freescale 56367 DSP engines, while the AVM-50 use just one of those processors.
Don't read much more into our test then what I have written. If sound quality is paramount to you, and you were questioning whether or not the DACs in varying price ranges of equipment will affect sound quality (as we are often led to believe), the four of us in Jon's room, using the equipment mentioned, in a very disciplined blind, level matched test, found that answer to be no.
I don't mean this to sound unkind Steve, but it is hard to read more in to what you have written, when what you have posted is so bereft of details (at least IMHO). Double blind testing is great, but you are still making basically subjective observations, are you not? There are enough Geeks here, that I would think some other quantifiable factual items would be of interest here. Since I just came from the Anthem web site, I'll c&p some of their sales points about the parts that they claim make a difference and why they believe they do help produce better sound.
-------------------------------------From Anthem Web Site --------------------------------------
"What makes an edge-of-the-art high-end preamplifier? Some say the quality of its component parts. For them the D2 exhibits an impressive résumébest-quality Crystal® analog attenuators, high-value ADC reference voltage decoupling capacitors, audio-grade Nichicon® MUSE® Series UK signal-coupling capacitors, low-ESR electrolytic OS-CON SVP capacitors, and the list goes on. For others, it's in the detailsthe number of design features compared with other high-end preamplifiers on the market. One simply has to glance at the D2's Design Overview (pages 5 and 6) to see why it is one of the most comprehensive, feature-laden high-end preamplifiers on the market. Finally, some use price to measure a preamplifier's worthit stands to reason the more expensive the preamplifier, the better the performance. Or does it? The D2's sonic presentation rivals that of the most expensive preamplifiers. Highs are refined, open and silky smooth. Mids are rich, full and exceptionally revealing. Bass presentation is articulate, with extraordinary power, depth and pace while still capturing the delicate edge of each leading bass note.
24-Bit/192-kHz Precision Upsampler
All Digital-to-Analog Conversion (DAC) uses a reconstruction filter as the final step in the conversion process. Without this filter, recreating the original signal would not be possible. The side-effect of this filtering, however, is a harshness in the upper frequenciesa result of audible errors in phase- and frequency-response. The best high-end DAC designs go to great lengths to minimize this distortion, with very good results. The D2, however, does even more
UPSAMPLING: Increases the sampling rate of the incoming digital signal. This allows the reconstruction filter to operate at a higher frequency, making it less intrusive in the audible bandwidth. While outboard Upsamplers can be purchased as an add-on component, their output is restricted to a maximum of 96 kHz due to the bandwidth limitation of S/PDIF (RCA/Toslink) and AES/EBU digital connections. When outboard Upsamplers are used with SSPs or separate DACs capable of 192 kHz they will, in reality, never operate at better than 96 kHz. In addition, they only operate on 2-channel PCM, not on decoded Dolby® Digital or DTS® program material.
The D2 includes its own built-in state-of-the-art Upsampler incorporating Analog Devices' AD 1896 and converts the sample rate of all incoming digital signals to 192 kHz. Since this is done completely inside the D2 there are no digital connections to limit the upsampling frequency. Our D/A converters then operate at their full 192 kHz capability. And unique to the D2, our Upsampler also operates on all decoded Dolby® Digital and DTS® program material.
OVERSAMPLING: Along with upsampling, the D2's DACs also incorporate 128X oversampling to increase the sample rate to 24.576 MHz, thereby ensuring the best phase- and frequency-response possible.
This combination of upsampling and oversampling allows the D2 to use much gentler 3rd-order Bessel reconstruction filters. Measurable results are profoundly superior, reflecting exceptionally flat frequency response and THD+N in the upper frequencies up to twenty times lower than some of the best high-end outboard DACs.
Sonic performance is astoundingsmoother high-frequency response, superior detail, better image focusin essence, a far more transparent window on the original performance. While this is enormously beneficial for music it is even more beneficial for home theater. Since the D2's Upsampler operates on all formats and all channels, the result is a much higher level of transparency for both multichannel music and movies.
Digital-to-Analog Converter (DAC)
Superior digital-to-analog conversion in the D2 is courtesy of our very high-quality DAC design. Here again, we have essentially eliminated ultrasonic noise and distortion in the 20 kHz to 80 kHz frequency band. Our six-layer converter boards use separate analog and digital planes as well as separate power- and groundplanes for the lowest noise possible. Since the D2 also includes our own built-in state-of-the-art Upsampler to convert the sample rate of any incoming digital signal to 192 kHz, the DACs are able to run at the highest speed (192 kHz), regardless of the incoming digital bitstream. The result is extremely low background noise up to almost 100 kHz.
AKM® AK4395 converters operate at their full 24-bit x 192-kHz resolution and switched-capacitor output filters significantly reduce the DAC's sensitivity to rapid fluctuations in the bit rate during the conversion process.
Audio-grade Nichicon® MUSE® Series UK signal-coupling capacitors with low-voltage coefficient ensure minimal distortion and low microphonicsdramatically reducing the DAC's sensitivity to vibration.
By eliminating the potential for errors in timing, our DAC's high-accuracy clock generator (49.152 MHz, ±0.001%) makes a substantial contribution to distortion-free performance.
Analog-to-Digital Converter (ADC)
Our use of the highest-quality ADCs essentially eliminates ultrasonic noise and distortion in the 20 kHz to 80 kHz frequency band. Dual independent six-layer converter boards use separate analog and digital planes as well as separate power- and groundplanes for remarkably low noise. The AKM® AK5495A ADCs are capable of up to 24-bit x 192-kHz resolution.
Analog input level is controlled through a balanced configuration of six highest-quality stereo Crystal® CS3310 analog attenuators arranged in differential modeone for each channel of the 6-channel input. This arrangement promotes greater dynamic range and contributes to an impressive reduction in distortion.
High-value (1,000 µF) ADC reference voltage decoupling capacitors provide the lowest possible THD+N below 1 kHz.
Low-ESR electrolytic OS-CON SVP capacitors are used to decouple the input stage bias reference voltage ensuring lower noise and distortion.
Audio-grade Nichicon® MUSE® Series UK signal-coupling capacitors with low-voltage coefficient ensure minimal distortion and low microphonics reducing the ADC's sensitivity to vibration."
----------------------------------------End Anthem C&P-------------------------------------------
My apologies if I have belabored the point here Steve, but I feel like your testing drew conclusions, but did not really answer any of the more obvious *why* questions, as is suggested by those conclusions. I mean, what is the point of such an elaborate test, if all you can tell us is that everything sounds the same, but you really can't tell us why that is. Is it possible that your testing process was simply not capable of discerning some of the less obvious differences?