|
|
Post by routlaw on Dec 8, 2021 19:21:11 GMT -5
Several days ago I started another thread regarding the ERC-4 and while it didn't gain much attention I also know there are many of us that own either the ERC-4 or ERC-3 and thought my delving into this might be of interest to those owners. What I have come to believe is the ERC-4, contrary to the claims of Emotiva, is not really a truly differential balanced device with anywhere near the output they claim. This afternoon it finally occurred to my why not compare the ERC-4's balanced outputs to its RCA unbalanced outputs. It came as no big surprise the RCA analog outputs play 4 db louder than the balanced outputs, more in line with my Oppo 203, yet still a bit lower in output. The specs page in the owners manual of the ERC-4 states 4 volts RMS output for 12 db of gain, while the RCA outputs have 2 volts RMS with 6 db of gain. Effectively this is a discrepancy of 10 db. FWIW I used a pair of BJC LC-1 for the RCA interconnects and a pair of Mogami 2534 for the balanced connection for comparison. Worth noting though I have also used BJC Belden 1800F, Pangea True Balanced Premium SE, and some DIY XLRs all with the same results. I suppose one could speculate the balanced XLR inputs to the RMC are not truly differential balanced designs either but that would not explain why the RCA still has more gain when clearly it shouldn't. I welcome any thoughts and would love to hear from the folks at Emotiva what they have to say about this. Also worth pointing out the player performs as it should other than lack of balanced output, and on this issue something is awry. Thanks emotivalounge.proboards.com/thread/59458/erc-4-mystery-solve |
|
|
|
Post by garbulky on Dec 8, 2021 20:08:55 GMT -5
Several days ago I started another thread regarding the ERC-4 and while it didn't gain much attention I also know there are many of us that own either the ERC-4 or ERC-3 and thought my delving into this might be of interest to those owners. What I have come to believe is the ERC-4, contrary to the claims of Emotiva, is not really a truly differential balanced device with anywhere near the output they claim. This afternoon it finally occurred to my why not compare the ERC-4's balanced outputs to its RCA unbalanced outputs. It came as no big surprise the RCA analog outputs play 4 db louder than the balanced outputs, more in line with my Oppo 203, yet still a bit lower in output. The specs page in the owners manual of the ERC-4 states 4 volts RMS output for 12 db of gain, while the RCA outputs have 2 volts RMS with 6 db of gain. Effectively this is a discrepancy of 10 db. FWIW I used a pair of BJC LC-1 for the RCA interconnects and a pair of Mogami 2534 for the balanced connection for comparison. Worth noting though I have also used BJC Belden 1800F, Pangea True Balanced Premium SE, and some DIY XLRs all with the same results. I suppose one could speculate the balanced XLR inputs to the RMC are not truly differential balanced designs either but that would not explain why the RCA still has more gain when clearly it shouldn't. I welcome any thoughts and would love to hear from the folks at Emotiva what they have to say about this. Also worth pointing out the player performs as it should other than lack of balanced output, and on this issue something is awry. Thanks emotivalounge.proboards.com/thread/59458/erc-4-mystery-solveAn ERC-4 could simply have differntial inputs and not be fully balanced and still put out 4V. Unless you measure the output, I don't know if you can say whether it is actually delivering the output. You can send your ERC-4 to audiosciencereview. They review the products for free. I'm still banking on the RMC-1 messing around with the signal. |
|
|
|
Post by routlaw on Dec 8, 2021 20:34:19 GMT -5
An ERC-4 could simply have differntial inputs and not be fully balanced and still put out 4V. Unless you measure the output, I don't know if you can say whether it is actually delivering the output. You can send your ERC-4 to audiosciencereview. They review the products for free. I'm still banking on the RMC-1 messing around with the signal. Thanks for the response, but the ERC-4 being a CDP does not have inputs in the way I think you are referring to. It does have Coax and optical inputs but this would not apply in this case. It’s the outputs we are concerned with here. The claim at Emotiva is a fully differentially balanced device with 4 vRMS balanced and 2vRMS RCA. Just playing cd’s only reflects the comments previously. Effectively until someone can prove otherwise its fairly obvious to me the player is NOT outputting its stated specs of 4 volts RMS. I’ll pass on ASR for now. While I know there is a lot of hatred for the G3 pre-pros at least in this case it doesn’t appear to be the culprit. Again I’m playing in reference stereo with both RCA and XLR and the difference is quite obvious. Thanks |
|
|
|
Post by routlaw on Dec 8, 2021 20:46:24 GMT -5
Addendum to my previous response. When I had the XPS-1 analog preamp (recently sold) and while making the same comparisons the results were the same. At the time I didn’t make much of it other than to scratch my and go on with the procedure. It’s only recently this has sort odd behavior has crawled under my skin. I also remember a few years ago when I owned the ERC-3 while comparing it to the Oppo 203 the results were once again, more output at the Oppo’s RCA outputs than the ERC-3 balanced outputs. At the time I was using the XMC-1 also in Reference stereo mode. Seemed odd at the time but again I didn’t turn it into a science project.
|
|
ttocs
Global Moderator 
I always have a wonderful time, wherever I am, whomever I'm with. (Elwood P Dowd)
Posts: 8,154
|
Post by ttocs on Dec 8, 2021 20:59:43 GMT -5
Have you measured the voltage of each output?
|
|
|
|
Post by garbulky on Dec 8, 2021 21:40:39 GMT -5
An ERC-4 could simply have differntial inputs and not be fully balanced and still put out 4V. Unless you measure the output, I don't know if you can say whether it is actually delivering the output. You can send your ERC-4 to audiosciencereview. They review the products for free. I'm still banking on the RMC-1 messing around with the signal. Thanks for the response, but the ERC-4 being a CDP does not have inputs in the way I think you are referring to. It does have Coax and optical inputs but this would not apply in this case. It’s the outputs we are concerned with here. The claim at Emotiva is a fully differentially balanced device with 4 vRMS balanced and 2vRMS RCA. Just playing cd’s only reflects the comments previously. Effectively until someone can prove otherwise its fairly obvious to me the player is NOT outputting its stated specs of 4 volts RMS. I’ll pass on ASR for now. While I know there is a lot of hatred for the G3 pre-pros at least in this case it doesn’t appear to be the culprit. Again I’m playing in reference stereo with both RCA and XLR and the difference is quite obvious. Thanks I'm sorry. I meant the ERC-4 XLR outputs to your RMC-1 balanced inputs? I'm thinking the RMC-1 is playing around with the signal even in reference stereo which is how Amir did his tests. See Lonnie's posts. audiosciencereview.com/forum/index.php?threads/emotiva-rmc-1-av-processor-review.11673/post-347128 |
|
|
|
Post by AudioHTIT on Dec 8, 2021 22:15:27 GMT -5
Thanks for the response, but the ERC-4 being a CDP does not have inputs in the way I think you are referring to. It does have Coax and optical inputs but this would not apply in this case. It’s the outputs we are concerned with here. The claim at Emotiva is a fully differentially balanced device with 4 vRMS balanced and 2vRMS RCA. Just playing cd’s only reflects the comments previously. Effectively until someone can prove otherwise its fairly obvious to me the player is NOT outputting its stated specs of 4 volts RMS. I’ll pass on ASR for now. While I know there is a lot of hatred for the G3 pre-pros at least in this case it doesn’t appear to be the culprit. Again I’m playing in reference stereo with both RCA and XLR and the difference is quite obvious. Thanks I'm sorry. I meant the ERC-4 XLR outputs to your RMC-1 balanced inputs? I'm thinking the RMC-1 is playing around with the signal even in reference stereo which is how Amir did his tests. See Lonnie's posts. audiosciencereview.com/forum/index.php?threads/emotiva-rmc-1-av-processor-review.11673/post-347128 In the post you reference, Lonnie is discussing Dolby / DTS code, I didn’t go back to try and find context, you think this is affecting a pure analog signal through the balanced ins? |
|
|
|
Post by garbulky on Dec 8, 2021 23:07:35 GMT -5
In the post you reference, Lonnie is discussing Dolby / DTS code, I didn’t go back to try and find context, you think this is affecting a pure analog signal through the balanced ins? Unclear. If you look at Emotiva's and ASR's thread Lonnie mentioned some things that were confusing. The test was performed in reference mode. |
|
|
|
Post by routlaw on Dec 8, 2021 23:21:21 GMT -5
Have you measured the voltage of each output? No I haven’t. |
|
|
|
Post by routlaw on Dec 8, 2021 23:23:50 GMT -5
I do want to emphasize these same test were also done on a purely analog pre-amp with the same results as with the RMC. I did not initially bring this up due to the complexity of so many different devices. I would go to my grave the RMC is NOT the issue here. It may have some faults but not related to this.
|
|
|
|
Post by routlaw on Dec 8, 2021 23:31:02 GMT -5
In the post you reference, Lonnie is discussing Dolby / DTS code, I didn’t go back to try and find context, you think this is affecting a pure analog signal through the balanced ins? Unclear. If you look at Emotiva's and ASR's thread Lonnie mentioned some things that were confusing. The test was performed in reference mode. From the link you’ve provided its discussing only digital processing which I don’t see relating to this issue. I seriously doubt the RMC is interfering with pure analog signals unless of course called upon to do so by the end user. Again at the risk of beating a dead horse on this I have done this same comparison over the last few years with other pre amps and received more or less the same results. I am inclined to believe anyone who owns either of these two players can easily duplicate what I have found. whoops just realized I quoted the wrong post, meant to quote garbulky. |
|
|
|
Post by garbulky on Dec 9, 2021 0:31:47 GMT -5
I do want to emphasize these same test were also done on a purely analog pre-amp with the same results as with the RMC. I did not initially bring this up due to the complexity of so many different devices. I would go to my grave the RMC is NOT the issue here. It may have some faults but not related to this. Ah...well never mind then since you tested on a different preamp. Hmmm... well that is interesting. If you have any other gear that have RCA and XLR outs you can test it on this analog preamp and see if you get the results you are expecting. (Which preamp was it btw?) Reason I ask is I use a fully balanced amp to my DC-1. I've also used unbalanced connections. I had never thought about that the volume would be audibly louder on XLR connections vs RCA connections because of the 4v vs 2v diffference. I wonder if it really has to be? |
|
|
|
Post by routlaw on Dec 9, 2021 10:18:25 GMT -5
Ah...well never mind then since you tested on a different preamp. Hmmm... well that is interesting. If you have any other gear that have RCA and XLR outs you can test it on this analog preamp and see if you get the results you are expecting. (Which preamp was it btw?) Reason I ask is I use a fully balanced amp to my DC-1. I've also used unbalanced connections. I had never thought about that the volume would be audibly louder on XLR connections vs RCA connections because of the 4v vs 2v diffference. I wonder if it really has to be? Yes as previously stated when using my Holo Spring DAC with balanced outputs its volume output into the RMC is closer to the results while using the RMC's built in DAC however its output is rated at 5.8 volts RMS which is a bit higher than normal. Typically analog outputs will tend to be around 2 vRMS for RCA and 4 vRMS for balanced. Below I have copied and pasted direct from the ERC-4 manual its stated output specs for both outputs and you can see the balanced outputs are double the RCA outputs, or so they should be. Typically the signal to noise ratio for balanced outputs is 6-10 db higher and this along with common mode noise rejection are why this type of circuit is so favored in the pro audio industry. Its not uncommon for them to run 50, 75, 100 or even 200 feet of cable either in a studio or stage environment. ERC-4 manual page 17 Output Level: Balanced outputs: +12 dBV (4V RMS). Unbalanced outputs: +6 dBV (2V RMS). It is possible my ERC-4 is defective due to its incorrect output, but I'm more inclined to think it is something in the design of these players and for what ever reason was never caught during production. The DAC chip itself is capable of differential reference balanced output but it appears something went wrong at the output stage. Worth noting with balanced designs you have a ground (pin 1) and two signals where pin 2 is + and pin 3 is - which allows the signal to cancel all noise from the line. Once the signal reaches the output circuit board the - signal is flopped or flipped which provides the additional gain known for balanced circuits. I suspect the ERC-4 output circuit board does not flop the - signal path and thus the output is now at somewhere around 1.4 volts RMS. This should have been caught a long time ago before these players were ever released. While I'm not one to be a heavy complainer this one seems inexcusable to me. |
|
|
|
Post by routlaw on Dec 9, 2021 10:22:00 GMT -5
Have you measured the voltage of each output? I would assume the way to do this is measure the DC voltage while playing a 1 kHz sine wave/test tone? But then how would one properly measure a balanced output since it has two signal wires? One lead on ground, the other on the + pin #2? Thanks |
|
ttocs
Global Moderator
I always have a wonderful time, wherever I am, whomever I'm with. (Elwood P Dowd)
Posts: 8,154
|
Post by ttocs on Dec 9, 2021 10:34:42 GMT -5
Have you measured the voltage of each output? I would assume the way to do this is measure the DC voltage while playing a 1 kHz sine wave/test tone? But then how would one properly measure a balanced output since it has two signal wires? One lead on ground, the other on the + pin #2? Thanks Use the web address below and slide down to the lower third of the page to see the diagram with the yellow meter and connections, then read how the test is setup and read Notes 1 & 2 below that. lab2104.tu-plovdiv.bg/index.php/2019/02/28/voltage-measurement-of-balanced-outputs/This is a quote from that page: " As can be seen, no matter what kind of equipment is being checked, the unbalanced dB meter or single-ended AC voltmeter is always connected as shown, and the equipment is terminated properly. If this is done, the following two statements will always be true:
1.) Whatever voltage is shown on the meter is exactly half the true output voltage.
2.) Whatever dB level shown on the meter is always 6dB less than the dB which the meter would show if it were able to be connected across the entire output." |
|
|
|
Post by routlaw on Dec 9, 2021 10:40:14 GMT -5
Just for the heck of it last evening upon discovering the considerable difference in the output from the RCA vs Balanced outs I thought a listening session comparing the two might be worthwhile. Again starting out with BJC LC-1 interconnects on the RCA and Mogami 2534 for the balanced outs the difference in sound quality really surprised given how different the two were. More like comparing two different CD players rather than cable/output combinations. As expected based upon my sound level measurements the RCA outputs played louder than the balanced outputs and it seemed more like 4.5 db instead of the measured 4 db earlier in the afternoon. This might be attributed to what I perceived as considerably more profound bass output, not necessarily better just abundant compared to the balanced outs with Mogami. The Mogami/XLR bass was more focused and precise and perhaps a bit more tuneful.
After a couple of hours of back and forth listening I gave up on which performed the best, yet still scratching my head on how different they presented the same music. This was not subtle at all. So much for "expectation bias" and at least in this case you could throw that neurosis out the window. The only thing concrete clear was the RCA outputs played louder by some 4 to 4.5 db compared to the balanced outputs when in fact the balanced outputs should have provided a bare minimum of 6 db more output over the RCA.
Emotiva, you have a problem.
|
|
|
|
Post by creimes on Dec 9, 2021 20:47:31 GMT -5
I have the ERC-4 as well so I could try testing the same as you, another option would be connect a XLR from the output of the ERC-4 AES/EBU to the RMC-1, I know this would use the RMC-1 DAC but curious of the findings, I myself don't have a actual AES/EBU XLR cable but a regular XLR one would work fine, good way to compare the DAC's between the RMC and ERC.
Chad
|
|
|
|
Post by routlaw on Dec 9, 2021 21:33:02 GMT -5
I have the ERC-4 as well so I could try testing the same as you, another option would be connect a XLR from the output of the ERC-4 AES/EBU to the RMC-1, I know this would use the RMC-1 DAC but curious of the findings, I myself don't have a actual AES/EBU XLR cable but a regular XLR one would work fine, good way to compare the DAC's between the RMC and ERC. Chad Thanks for the suggestion, but have been doing this almost as long as I’ve had the ERC-4. Using this method the ERC-4 to RMC exhibited some 14-15 db higher volume than its XLR analog outputs. It was this substantial difference that inspired me to chase down this rabbit hole because it made no logical or technical sense. Effectively using the player as a transport only with coax or AES rendered the same volume results as with my Mac Mini and USB cable. I’ve measured all 3 and they were identical although each sounded considerably different. Thanks |
|
|
|
Post by brutiarti on Dec 9, 2021 21:42:09 GMT -5
I have the ERC-4 as well so I could try testing the same as you, another option would be connect a XLR from the output of the ERC-4 AES/EBU to the RMC-1, I know this would use the RMC-1 DAC but curious of the findings, I myself don't have a actual AES/EBU XLR cable but a regular XLR one would work fine, good way to compare the DAC's between the RMC and ERC. Chad Thanks for the suggestion, but have been doing this almost as long as I’ve had the ERC-4. Using this method the ERC-4 to RMC exhibited some 14-15 db higher volume than its XLR analog outputs. It was this substantial difference that inspired me to chase down this rabbit hole because it made no logical or technical sense. Effectively using the player as a transport only with coax or AES rendered the same volume results as with my Mac Mini and USB cable. I’ve measured all 3 and they were identical although each sounded considerably different. Thanks Indeed the balance analog connections offer less volume than the analog RCA’s. |
|
|
|
Post by creimes on Dec 9, 2021 22:00:18 GMT -5
I have the ERC-4 as well so I could try testing the same as you, another option would be connect a XLR from the output of the ERC-4 AES/EBU to the RMC-1, I know this would use the RMC-1 DAC but curious of the findings, I myself don't have a actual AES/EBU XLR cable but a regular XLR one would work fine, good way to compare the DAC's between the RMC and ERC. Chad Thanks for the suggestion, but have been doing this almost as long as I’ve had the ERC-4. Using this method the ERC-4 to RMC exhibited some 14-15 db higher volume than its XLR analog outputs. It was this substantial difference that inspired me to chase down this rabbit hole because it made no logical or technical sense. Effectively using the player as a transport only with coax or AES rendered the same volume results as with my Mac Mini and USB cable. I’ve measured all 3 and they were identical although each sounded considerably different. Thanks I'm curious to try it on my XMC-1 using the AES/EBU but I really like the analog out of the ERC-4 so I've been too lazy haha, but now I'm curious to try the RCA to my XMC-1. Cheers, Chad |
|
