A great idea.
I think it would be worthwhile for a rebuttal or analysis
by a tech experts on ASR.
Here is the conclusion:
They are clearly insinuating that ASR is lacking in "technical accuracy".
This is my summary of the response:
- The product was "understood to be B-Stock"
- ASR Vol 78 us 4V rms. design output is 2V rms XLR and 1V RCA
- ASR fell into a ground-loop issue
- 1kHz tone measured with limited 10Hz to 29 kHz bandwidth
- Intermodulation Distortion -101 dB when bandwidth limited to 20 kHz
- Jitter test issues are due to 16-bit not 24 bit test and ground-loop
- DAC Reconstruction by design filter design for alleviate pre-ringing also, bandlimit to 22 kHz
- 32 tone test is not representative of music because of high amplitude at high-frequencies. Using two-tone 19khz and 20Khz. Note: relatively high spikes are present 28 and 29 kHz.
It seems like this product output voltage has reduced to a relatively low 2V RMS XLR to achieve better results. This device is rated for 1 volt RCA and 2 volt XLR, this is ridiculous for a product at this price point. The answer, buy Arcam amps
The ground-loop is unproved and certainly not atypical of the real-word where multiple sources are normal. Normal is not a pattern generator and measurement from an analyzer.
Bandwidth limiting is used to improve the results. For some reason, 6 kHz was selected as an upper limit to improve the reported results.
Perhaps, this response would make sense if other >$4000 processors had 2V RMS XLR limits, bad reconstruction filters, and lots of out-of-band noise. The specifications appear to have been written after the design.
A response will take a lot of posts however from even one person, if lots of people contribute the response will cover may pages, but that seems fine. Chime in if you find I've made a mistake(s). Have the Arcam document open since you'll need to refer to it.
The response from Arcam is great fun and will provide days of entertainment since it is a target rich environment. Things were a little quiet so someone please send Arcam a thank you note.
Feedback on form of response:
- Who wrote it, the person(s), organization and location?
- Where's the email address for responses and questions? Amir is out in the open. The authors of the response don't give their names and contact information.
- Why aren't the pages numbered and the document dated? Pure amateur hour.
(You were warned, this will be long!)
ASR is making measurements of the Arcam 40 based on criteria established by ASR. The ASR piece isn't a test to determine if Arcam meets Arcam's specifications, the piece is a set of measurements based on criteria ASR, with input from site members, has determined are important in an AVR/AVP.
For perspective: Sorry rookie, but this is the big's, you didn't see 95 mph fast balls down in AA or in college. If you want to stay in the show you'll have to excel at this level. There is no crying in baseball!
1V out from RCA's (single-ended, SE) won't most power amplifiers to full output. (1V into a typical power amplifier with a 28 to 29dB gain will only produce 100W). 2V from XLR's isn't' enough voltage to drive multichannel amplifiers from sources such as Marantz (example, MM8077), Parasound (example, A52+), and won't make the best use of XLR inputs from companies from Bryston to Benchmark.
Bottom-line 4V from XLR's, which normally means 2V from RCA is valid test benchmark. 1V RCA's, 2V XLR's is unacceptable regardless of whether the unit meets it. So there is no reason to test at 1V and 2V.
Concerning the multiplexer: The measurement isn't at 4V SE, the measurement is at 4V from an XLR (balanced, +/- 2V). Whether the internal architecture is balanced or SE internally, 2V per single line maximum is being handled assuming the DAC outputs 2V, or 2V after the I/V conversion if the current output mode is used from the ESS DAC IC. 4V balanced is 2 x 2V SE lines, otherwise a 2V SE drives a double opamp stage with a follower and an inverter stage to get 4V. Nothing in this signal chain is handling over 2V so the writer doesn't understand how any of this works. Hopefully the writer wasn't the designer.
There are excellent products, such as the OPPO BDP105 (and likely all OPPO's, I don't know) where both the digital outputs (HDMI, coax) and analog outputs (RCA, pin 1 of XKR) outputs are grounded to the case. This means the analog and digital grounds are connected. This connection exists in most D/M gear as well. In D/M gear the digital and analog grounds are connected at the DAC IC based on AKM specifications. Does this mean that OPPO's can't be used with the AV40 with both wired digital and analog outputs connected to the AV40, without the output of the AV40 being negatively affected by the ground loop that will be created according to the text in the Arcam response. If so, this is unacceptable.
In one older Yamaha AVR that I tested (RXV 3010), the digital and analog grounds aren't connected. This may be true for all Yamaha's AVR's of this series since they change little over the years. It appears this is true from the schematics, but I can't be sure. Do all Yamaha's have this ground loop issue when used with OPPO's? Anyone used that connection? Does this connection make a chattering noise?
Is the AV40 only usable in A/V systems that use Class 2 electrical safety? That is, are connected only with a two conductor power cable with no third, safety ground connection (Class 1)? If only Class 2 equipment is allowed then some of the best equipment in the world is eliminated. The AV40 must have a really amateurish electrical design if it can't be use in systems with Class 1 gear. Denon/Marantz and numerous other companies produce Class 2 equipment that can work without issue along side Class 1 gear.
That is enough for now. The response from Arcam is in many ways makes the AV40 appear worse than the ASR measurements IMO.