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Post by conmoto on Apr 25, 2022 21:37:59 GMT -5
I was doing an A-B comparison between the DC-1 and a Topping D90se/tube pre and the left and right channels are reversed. I can't explain why.
A) Mac USB -> D90se RCA -> Tube Pre RCA -> DC-1 RCA -> Headphone. Left and Right are correct.
B) Mac USB -> DC-1 -> Headphone. Left and Right are reversed/incorrect.
Why is this happening. Why does it bug me so much?!
Regarding the comparison, there is a slight bit of tubey magic added compared to the DC-1 alone. I'd like to do a blind test for a more objective assessment. The calming glow of the tubes may be throwing me off :-) Bottom line is that the DC-1 is still one hell of a DAC/headphone amp after all these years. What a great value.
Thanks in advance for your input.
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Post by 405x5 on Apr 26, 2022 8:46:52 GMT -5
I was doing an A-B comparison between the DC-1 and a Topping D90se/tube pre and the left and right channels are reversed. I can't explain why. A) Mac USB -> D90se RCA -> Tube Pre RCA -> DC-1 RCA -> Headphone. Left and Right are correct.B) Mac USB -> DC-1 -> Headphone. Left and Right are reversed/incorrect.Why is this happening. Why does it bug me so much?! Regarding the comparison, there is a slight bit of tubey magic added compared to the DC-1 alone. I'd like to do a blind test for a more objective assessment. The calming glow of the tubes may be throwing me off :-) Bottom line is that the DC-1 is still one hell of a DAC/headphone amp after all these years. What a great value. Thanks in advance for your input. [br You have a lot of interconnect going on there. Simply swap the channels at the easiest point whichever that is for your system. It could be the headphone wire it could be the interconnects doesn’t matter just do the easiest one. |
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KeithL
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Post by KeithL on Apr 26, 2022 10:13:40 GMT -5
I agree - there are a lot of points where it could be getting swapped. And, depending on what player program you use, there may even be an option to swap channels in that. (I'm pretty sure the DC-1 isn't reversing it - but I have no handy way to check at this point.)
I would definitely try that blind comparison. (I'm not a huge fan of "tube sound" - at least not with most high quality content - and the DC-1 is a VERY nice sounding DAC.)
I was doing an A-B comparison between the DC-1 and a Topping D90se/tube pre and the left and right channels are reversed. I can't explain why. A) Mac USB -> D90se RCA -> Tube Pre RCA -> DC-1 RCA -> Headphone. Left and Right are correct.B) Mac USB -> DC-1 -> Headphone. Left and Right are reversed/incorrect.Why is this happening. Why does it bug me so much?! Regarding the comparison, there is a slight bit of tubey magic added compared to the DC-1 alone. I'd like to do a blind test for a more objective assessment. The calming glow of the tubes may be throwing me off :-) Bottom line is that the DC-1 is still one hell of a DAC/headphone amp after all these years. What a great value. Thanks in advance for your input. [br You have a lot of interconnect going on there. Simply swap the channels at the easiest point whichever that is for your system. It could be the headphone wire it could be the interconnects doesn’t matter just do the easiest one. |
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Post by AudioHTIT on Apr 26, 2022 12:20:35 GMT -5
I was doing an A-B comparison between the DC-1 and a Topping D90se/tube pre and the left and right channels are reversed. I can't explain why. A) Mac USB -> D90se RCA -> Tube Pre RCA -> DC-1 RCA -> Headphone. Left and Right are correct.B) Mac USB -> DC-1 -> Headphone. Left and Right are reversed/incorrect.Why is this happening. Why does it bug me so much?! Regarding the comparison, there is a slight bit of tubey magic added compared to the DC-1 alone. I'd like to do a blind test for a more objective assessment. The calming glow of the tubes may be throwing me off :-) Bottom line is that the DC-1 is still one hell of a DAC/headphone amp after all these years. What a great value. Thanks in advance for your input. You have a lot of interconnect going on there. Simply swap the channels at the easiest point whichever that is for your system. It could be the headphone wire it could be the interconnects doesn’t matter just do the easiest one. I agree - there are a lot of points where it could be getting swapped. And, depending on what player program you use, there may even be an option to swap channels in that. (I'm pretty sure the DC-1 isn't reversing it - but I have no handy way to check at this point.)
I would definitely try that blind comparison. (I'm not a huge fan of "tube sound" - at least not with most high quality content - and the DC-1 is a VERY nice sounding DAC.)
In the case of scenario B I’d have to disagree, it couldn’t be much simpler, and without a kludgy headphone adapter, impossible to (electrically) change. In fact the only way I can see for B to be wrong would be to put your headphones on reversed, or to have a channel reversed HP cable — both could be checked with a VOM. Granted, lots of opportunity for cabling errors with scenario A, but we have to assume that was double checked before posting (and also assume that the OP isn’t looking for a solution, but rather an explanation). Testing Scenario B: For reference, on the HP TRS plug, the Tip is Left, the Ring is Right, the Sleve is Common/Shield. If I put my HPs on properly, set my VOM to low ohms, and tap the probes between the Sleeve and Tip, I hear a pop in my Left ear; between Sleeve and Ring, a pop in my Right ear. I can also plug them directly into my MacBook and play Left & Right channel test tones and hear them in the proper ear, so that would seem to eliminate any HP errors. Finally I tested: Mac mini > USB > DC-1 > Headphone Jack > Headphones (I even tested both jacks). Using the Mac’s MIDI utility both to select the DC-1, and to generate the test tones, my L/R output was correct. So in my opinion, the DC-1 is NOT the culprit in the erroneous outcome for Scenario B (at least my DC-1 is wired properly). I would figure out what’s wrong with your Scenario B, before trying to consider Scenario A. Here are the screens from my tests:   |
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Post by conmoto on Apr 26, 2022 13:41:36 GMT -5
“… assume that the OP isn’t looking for a solution, but rather an explanation” Correct!
I checked RCA and HP cables for correct inputs. Everything “appears” correct. Headphones were worn correctly. The ONLY change from A to B was to pull the USB from the D90se and plug it into the DC-1.
The only thing I failed to mention was that a 4.4 to 1/8” HP adapter is in use.
What is VOM?
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Post by mountain on Apr 26, 2022 14:07:41 GMT -5
VOM = Volt-Ohm-Milliammeter, another name for a multimeter
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KeithL
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Post by KeithL on Apr 26, 2022 14:35:36 GMT -5
The term "VOM" usually means "Volt-Ohm Milliammeter" - which is the old term for the old version of what we now call a DMM ("digital multimeter")....
Among other things they can be used as a continuity tester to determine which pins go where in an audio cable.
In a USB cable the two signals travel together so they cannot actually get "crossed" in a USB cable. However it's possible that the DC-1 flips them and nobody has noticed it before (but I really doubt it). It's also not impossible that the RCA outputs on your particular unit somehow got mis-wired.
You could try plugging a pair of regular headphones directly into the DC-1 ...
(the wires inside the DC-1 going from the circuit board are going to the outputs are very short so I doubt they
I can tell you that I just played Al Stewart's song Year of the Cat on a DC-1 here... And that song starts out in only the left channel... And it played in the correct channel from the headphone output on the DC-1 .... And from the analog RCA output on the DC-1 ...
And from that same channel on a different DAC (connected to the same computer and program)...
However, regardless, there are lots of places where it could have gotten flipped, and the easiest way to flip it back is just to flip the left and right wires wherever it's convenient to do so. “… assume that the OP isn’t looking for a solution, but rather an explanation” Correct! I checked RCA and HP cables for correct inputs. Everything “appears” correct. Headphones were worn correctly. The ONLY change from A to B was to pull the USB from the D90se and plug it into the DC-1. The only thing I failed to mention was that a 4.4 to 1/8” HP adapter is in use. What is VOM? |
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Post by AudioHTIT on Apr 26, 2022 14:40:53 GMT -5
“… assume that the OP isn’t looking for a solution, but rather an explanation” Correct! I checked RCA and HP cables for correct inputs. Everything “appears” correct. Headphones were worn correctly. The ONLY change from A to B was to pull the USB from the D90se and plug it into the DC-1. The only thing I failed to mention was that a 4.4 to 1/8” HP adapter is in use. What is VOM? Ah, so you do have a “Kludgy headphone adapter” 😀 I had to lookup what a 4.4 was, it sounds like your headphones aren’t run of the mill. Certainly the adapter would be suspect, but understand it would be the same for A & B, I would continue to focus on B as that’s the simplest path and the best place to troubleshoot. If you don’t have a VOM/Multimeter (thanks mountain), you could also use a 1.5v battery to generate the test signal and “pop”. It would be good to do it with and without the adapter. Do you have any other headphones or earbuds with a 3.5 / 1/8” plug to test without the adapter? |
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Post by AudioHTIT on Apr 26, 2022 14:48:02 GMT -5
… In a USB cable the two signals travel together so they cannot actually get "crossed" in a USB cable. However it's possible that the DC-1 flips them and nobody has noticed it before (but I really doubt it). … As mentioned, my DC-1 tests properly, so unless there was a bad build, I doubt it as well. (though in scenario A he’s using the analog in so it’s possible they are reversed, haven’t tested that). |
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KeithL
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Post by KeithL on Apr 26, 2022 15:50:47 GMT -5
How about plugging the 1/8 adapter from the headphones straight into the headphone output on the computer's sound card? (Most computers still have one of those.)
“… assume that the OP isn’t looking for a solution, but rather an explanation” Correct! I checked RCA and HP cables for correct inputs. Everything “appears” correct. Headphones were worn correctly. The ONLY change from A to B was to pull the USB from the D90se and plug it into the DC-1. The only thing I failed to mention was that a 4.4 to 1/8” HP adapter is in use. What is VOM? Ah, so you do have a “Kludgy headphone adapter” 😀 I had to lookup what a 4.4 was, it sounds like your headphones aren’t run of the mill. Certainly the adapter would be suspect, but understand it would be the same for A & B, I would continue to focus on B as that’s the simplest path and the best place to troubleshoot. If you don’t have a VOM/Multimeter (thanks mountain ), you could also use a 1.5v battery to generate the test signal and “pop”. It would be good to do it with and without the adapter. Do you have any other headphones or earbuds with a 3.5 / 1/8” plug to test without the adapter? |
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Post by AudioHTIT on Apr 26, 2022 15:59:17 GMT -5
How about plugging the 1/8 adapter from the headphones straight into the headphone output on the computer's sound card? (Most computers still have one of those.)
Ah, so you do have a “Kludgy headphone adapter” 😀 I had to lookup what a 4.4 was, it sounds like your headphones aren’t run of the mill. Certainly the adapter would be suspect, but understand it would be the same for A & B, I would continue to focus on B as that’s the simplest path and the best place to troubleshoot. If you don’t have a VOM/Multimeter (thanks mountain ), you could also use a 1.5v battery to generate the test signal and “pop”. It would be good to do it with and without the adapter. Do you have any other headphones or earbuds with a 3.5 / 1/8” plug to test without the adapter? Yes, I did that test as well (most Macs do have an 1/8" HP jack), and it would eliminate the DC-1 and just test the headphones w/adapter, good idea! |
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