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OpenHeart cables tested using multimeter

JIW

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Nov 11, 2019
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Germany
I have tested two OpenHeart cables with a Crenova 890Z multimeter. Both are for Sennheiser HD600 series headphones (580, 600, 650, 660S/S2) and are each 2 meters long. One has a 6.35 mm TRS plug and the other has a 4.4 mm TRRRS plug also known as Pentaconn. I bought them on aliexpress to replace the stock HD650 cable that is too long for me currently, leading me to have to coil it on the desk. However, when pulled on enough it uncoils and getting it back into a nice coil is quite finicky. Alas, by the time the cables arrived from China, I had found a solution by using a velcro tie on the coil. Further, at 2 meters in length, they hang barely of the floor with the headphones on the desk, risking to be stepped on or rolled over by the chair. I knew before ordering that 1.4 meters would be too short but only found out 2 meters would be too long when the cables where already underway. I bought the 4.4 mm in particular to try the connector on my SMSL DL200.

I measured the impedances between connections on the cable to check for proper wiring of all 16 cores. Impedance from one segment of the plugs to another is beyond the meters ability of 9999 MOhm and thus displayed as OL. This indicates that all cores are correctly wired or at least that there are none wired incorrectly as some may not be connected at all. Impedances between plug and connector are displayed as 0.0 Ohm - the lowest the meter can show. The impedance between the negative connectors on the TRS cable is 0.2 Ohm. The impedance between all other connectors on either cable is displayed as OL. The TRS is wired correctly with the tip being the left positive, the ring being the right positive and the sleeve being ground. The TRRRS is wired correctly as well with the tip being left positive, the first ring being left negative, the second ring being right positive, the third ring being right negative and the sleeve not being connected.

The 4.4 mm connector is covered in heatshrink which moves when the pulling or pushing the plug into the tight jack of my SMSL DL200. The distance from the top of the splitter to the tip of the connectors is 44 cm. This is long enough to get stuck on the underside of the table. However, I have had no issues with that sofar unless forcing it by holding it in place. Still, it was not enoiugh to dislodge the headphones. Even though the connectors are long, they only barely touch my shoulders when turning my head all the way right or left without tilting it down. The stock HD650 cable connectors also do this. However, while the connector bodies extends the same length from the headphone when inserted, the Openheart cable has some fairly stiff heatshrink below it which may restrict range of motion somewhat. Either way, however I moved my head, I could not dislodge the headphones.

The weave separates when the cable is bent at an acute angle or pushed together. This is unnerving to me, but may not be an issue.

In terms of sound, in a simple sighted test, listening to the new to me 4.4 mm OpenHeart cable and then the stock HD650 cable I used before, the sound is very similar and I don't think I could identify them blinded. Then again, I was not expecting any differences.

Overall, since they don't do anything better for me than the stock HD650 cable does now, I will probably return them, but they are well constructed as far as I can tell.
 
...since they don't do anything better for me than the stock HD650 cable does now, I will probably return them, but they are well constructed as far as I can tell.
To China?
 
I measured the impedances between connections on the cable to check for proper wiring of all 16 cores. Impedance from one segment of the plugs to another is beyond the meters ability of 9999 MOhm and thus displayed as OL.
That would be open (infinite resistance = no connection).

They should measure approximately zero-Ohms (a "direct connection" or a "short") end-to-end where there should be a connection and open where there shouldn't be a short.

Low resistance measurements are difficult to do accurately. No meter is "perfect" and there is resistance in the leads and the connections at both ends of the probes. As long as you read near zero where there should be a connection and infinity where there shouldn't be a connection, everything is fine.

The sound is very similar and I don't think I could identify them blinded. Then again, I was not expecting any differences.
Good! Most audio cables don't affect the sound (as long as it's the appropriate type of cable). And headphone cables are generally the least critical. If they are working there's no need to measure them. ;)
 
That would be open (infinite resistance = no connection).

They should measure approximately zero-Ohms (a "direct connection" or a "short") end-to-end where there should be a connection and open where there shouldn't be a short.

Low resistance measurements are difficult to do accurately. No meter is "perfect" and there is resistance in the leads and the connections at both ends of the probes. As long as you read near zero where there should be a connection and infinity where there shouldn't be a connection, everything is fine.


Good! Most audio cables don't affect the sound (as long as it's the appropriate type of cable). And headphone cables are generally the least critical. If they are working there's no need to measure them. ;)
I was measuring mostly to confirm proper wiring.
 
I was measuring mostly to confirm proper wiring.
Have you had an issue with headphone cables that weren't properly wired?
 
I have tested two OpenHeart cables with a Crenova 890Z multimeter. Both are for Sennheiser HD600 series headphones (580, 600, 650, 660S/S2) and are each 2 meters long. One has a 6.35 mm TRS plug and the other has a 4.4 mm TRRRS plug also known as Pentaconn. I bought them on aliexpress to replace the stock HD650 cable that is too long for me currently, leading me to have to coil it on the desk. However, when pulled on enough it uncoils and getting it back into a nice coil is quite finicky. Alas, by the time the cables arrived from China, I had found a solution by using a velcro tie on the coil. Further, at 2 meters in length, they hang barely of the floor with the headphones on the desk, risking to be stepped on or rolled over by the chair. I knew before ordering that 1.4 meters would be too short but only found out 2 meters would be too long when the cables where already underway. I bought the 4.4 mm in particular to try the connector on my SMSL DL200.

I measured the impedances between connections on the cable to check for proper wiring of all 16 cores. Impedance from one segment of the plugs to another is beyond the meters ability of 9999 MOhm and thus displayed as OL. This indicates that all cores are correctly wired or at least that there are none wired incorrectly as some may not be connected at all. Impedances between plug and connector are displayed as 0.0 Ohm - the lowest the meter can show. The impedance between the negative connectors on the TRS cable is 0.2 Ohm. The impedance between all other connectors on either cable is displayed as OL. The TRS is wired correctly with the tip being the left positive, the ring being the right positive and the sleeve being ground. The TRRRS is wired correctly as well with the tip being left positive, the first ring being left negative, the second ring being right positive, the third ring being right negative and the sleeve not being connected.

The 4.4 mm connector is covered in heatshrink which moves when the pulling or pushing the plug into the tight jack of my SMSL DL200. The distance from the top of the splitter to the tip of the connectors is 44 cm. This is long enough to get stuck on the underside of the table. However, I have had no issues with that sofar unless forcing it by holding it in place. Still, it was not enoiugh to dislodge the headphones. Even though the connectors are long, they only barely touch my shoulders when turning my head all the way right or left without tilting it down. The stock HD650 cable connectors also do this. However, while the connector bodies extends the same length from the headphone when inserted, the Openheart cable has some fairly stiff heatshrink below it which may restrict range of motion somewhat. Either way, however I moved my head, I could not dislodge the headphones.

The weave separates when the cable is bent at an acute angle or pushed together. This is unnerving to me, but may not be an issue.

In terms of sound, in a simple sighted test, listening to the new to me 4.4 mm OpenHeart cable and then the stock HD650 cable I used before, the sound is very similar and I don't think I could identify them blinded. Then again, I was not expecting any differences.

Overall, since they don't do anything better for me than the stock HD650 cable does now, I will probably return them, but they are well constructed as far as I can tell.
In order to measure resistances that low accurately, you would need an ohmmeter that has 4-wire, also called kelvin connection capability. Using a 2-wire meter will introduce excessive error because the meter's wires have some resistance and the points of contact of the meter's probes add more resistance. The kelvin connection eliminate those errors, which can be larger than the tiny resistance you are measuring.
 
It goes to Dresden with DHL.
Where in Germany exactly did you order it? I'm interested in a balanced cable for my HD800, for connection to my Qudelix 5k with 2.5mm TRRS plug (if there is such a cable).
 
Using a 2-wire meter will introduce excessive error
We can only hope that the DMM in use during these Ohmic measurement were not sourced similarly.
Decade ago, when HarborTool&Freight used to give away those free DMMs; I used to give them away to those that would get use out of a DMM (in their toolbox).
Then, I realized that I was doing - the uninitiated - a disservice by giving them those crappy DMMs.;)
 
I have tested two OpenHeart cables with a Crenova 890Z multimeter. Both are for Sennheiser HD600 series headphones (580, 600, 650, 660S/S2) and are each 2 meters long. One has a 6.35 mm TRS plug and the other has a 4.4 mm TRRRS plug also known as Pentaconn. I bought them on aliexpress to replace the stock HD650 cable that is too long for me currently, leading me to have to coil it on the desk. However, when pulled on enough it uncoils and getting it back into a nice coil is quite finicky. Alas, by the time the cables arrived from China, I had found a solution by using a velcro tie on the coil. Further, at 2 meters in length, they hang barely of the floor with the headphones on the desk, risking to be stepped on or rolled over by the chair. I knew before ordering that 1.4 meters would be too short but only found out 2 meters would be too long when the cables where already underway. I bought the 4.4 mm in particular to try the connector on my SMSL DL200.

I measured the impedances between connections on the cable to check for proper wiring of all 16 cores. Impedance from one segment of the plugs to another is beyond the meters ability of 9999 MOhm and thus displayed as OL. This indicates that all cores are correctly wired or at least that there are none wired incorrectly as some may not be connected at all. Impedances between plug and connector are displayed as 0.0 Ohm - the lowest the meter can show. The impedance between the negative connectors on the TRS cable is 0.2 Ohm. The impedance between all other connectors on either cable is displayed as OL. The TRS is wired correctly with the tip being the left positive, the ring being the right positive and the sleeve being ground. The TRRRS is wired correctly as well with the tip being left positive, the first ring being left negative, the second ring being right positive, the third ring being right negative and the sleeve not being connected.

The 4.4 mm connector is covered in heatshrink which moves when the pulling or pushing the plug into the tight jack of my SMSL DL200. The distance from the top of the splitter to the tip of the connectors is 44 cm. This is long enough to get stuck on the underside of the table. However, I have had no issues with that sofar unless forcing it by holding it in place. Still, it was not enoiugh to dislodge the headphones. Even though the connectors are long, they only barely touch my shoulders when turning my head all the way right or left without tilting it down. The stock HD650 cable connectors also do this. However, while the connector bodies extends the same length from the headphone when inserted, the Openheart cable has some fairly stiff heatshrink below it which may restrict range of motion somewhat. Either way, however I moved my head, I could not dislodge the headphones.

The weave separates when the cable is bent at an acute angle or pushed together. This is unnerving to me, but may not be an issue.

In terms of sound, in a simple sighted test, listening to the new to me 4.4 mm OpenHeart cable and then the stock HD650 cable I used before, the sound is very similar and I don't think I could identify them blinded. Then again, I was not expecting any differences.

Overall, since they don't do anything better for me than the stock HD650 cable does now, I will probably return them, but they are well constructed as far as I can tell.
What would be more interesting to know is how supple they are and above all if they are microphonic or not and what the price is.
Pictures of the cables used would help as well.

For HD6xx range the resistance, capacitance and inductance and conductor material don't really matter so am not interested in that for the sennheisers but resistance could be relevant (ohm/meter/wire) for low impedance headphones, specifically the single entry 3-wire cables.
 
In order to measure resistances that low accurately, you would need an ohmmeter that has 4-wire, also called kelvin connection capability. Using a 2-wire meter will introduce excessive error because the meter's wires have some resistance and the points of contact of the meter's probes add more resistance. The kelvin connection eliminate those errors, which can be larger than the tiny resistance you are measuring.
Another way is to use a lab power supply, set current to 1 Amp through the cable and measure the voltage across the cable on the connectors. This way you can use a 2-wire multimeter with 200mV or 300mV DC range. :)
 
Where in Germany exactly did you order it? I'm interested in a balanced cable for my HD800, for connection to my Qudelix 5k with 2.5mm TRRS plug (if there is such a cable).
I ordered in on aliexpress. It was delivered from China. Only the return address is in Germany.
 
What would be more interesting to know is how supple they are and above all if they are microphonic or not and what the price is.
Pictures of the cables used would help as well.

For HD6xx range the resistance, capacitance and inductance and conductor material don't really matter so am not interested in that for the sennheisers but resistance could be relevant (ohm/meter/wire) for low impedance headphones, specifically the single entry 3-wire cables.
It is about as microphonic as the stock HD650 cable if not a bit less. The only problem may be occasional contact between the splitter and the table bottom. It is quite flexible but not suitable for tight bends. Also, it is not equally flexible in all directions since the weave is more like 3 by 5 wires than 4 by 4. See the second image. Price was 33.79€ for each at time of purchase with some discounts later reducing it further. Current price is 38.99€ for each. There are plenty of pictures on the aliexpress page such as the one below. Here is the German one I ordered from. The connectors are as displayed when using the menu. The heatshrink on the 4.4 mm can be removed and the plug is the same as in the product pictures. I cannot take any additional pictures because it is already packed up.
1743713468382.png

1743713673608.png
 
Where in Germany exactly did you order it? I'm interested in a balanced cable for my HD800, for connection to my Qudelix 5k with 2.5mm TRRS plug (if there is such a cable).
Also, this cable from OpenHeart fits your description.
1743714416830.png
 
In order to measure resistances that low accurately, you would need an ohmmeter that has 4-wire, also called kelvin connection capability. Using a 2-wire meter will introduce excessive error because the meter's wires have some resistance and the points of contact of the meter's probes add more resistance. The kelvin connection eliminate those errors, which can be larger than the tiny resistance you are measuring.
Fair point. As I was already saying above, I measured impedance to check the wiring. The impedances being either very low or too high for the metre was sufficient for that.
 
Fair point. As I was already saying above, I measured impedance to check the wiring. The impedances being either very low or too high for the metre was sufficient for that.
For go-no go testing, your technique is adequate.
 
It needs another adapter from 4.4 mm TRRS to 2.5 mm TRRS, like this one.
It can be ordered with 2.5 mm TRRS. Check the link. There are just no pictures from the seller of one.
 
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