Raal Ribbon Headphones - SRH1A
Feb 14, 2020 at 6:18 AM Post #1,877 of 7,842
Edit: Thenewguy007 beat me too it.
 
Feb 14, 2020 at 1:19 PM Post #1,879 of 7,842
Hi Guys - Thanks for all the information available in this thread. It has helped immensely.

I received my SR1a headphones today and quickly ran into an issue that I'd love some help with. Perhaps someone else has run into this same issue.

When I set the SR1a headphones down, the metal pieces on the end of the L+R cables, touch causing the pair of Schiit Vidar amps to go into protection mode. This only happens when music is playing of course. Seems like a poor design of the cables or something else is afoot.

Question: Has anyone else experienced this or does anyone have any thoughts about it?



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Are you talking about the Black and Red housings? That's strange because those are normally made of non-conductive material.
 
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Feb 14, 2020 at 1:28 PM Post #1,880 of 7,842
Are you talking about the Black and Red housings? That's strange because those are normally made of non-conductive material.
Yes. On mine they are both silver metal.

Today I switched all the electronics over to an isolation transformer with impeccable grounding and the issue is gone. Perhaps the outlet by my desk isn't grounded properly. Nonetheless, the fact that these are conductive is a strange one.
 
Feb 15, 2020 at 4:58 PM Post #1,883 of 7,842
Preliminary resistor testing is suggesting a phenomenal amount of performance potential is possible from standard speaker amplifiers when the very best resistors are used in the interface box. Yes resistor quality matters in this application as well. Even a single resistor in the signal path degrades performance. Let alone 72 of them. There's some new resistors on the market that are damn near as transparent as a straight wire. But the lead time is quite long, and only 1 factory in the world has the technology to produce them.
 
Feb 15, 2020 at 5:24 PM Post #1,885 of 7,842
Feb 15, 2020 at 6:11 PM Post #1,886 of 7,842
It seems to be, but it's just odd that there's no insulation on the cables at the metal connectors to prevent this.
Hi Chris,
The connector shell is connected to ground lead (or negative lead).
It never occurred to me that the two connectors will touch and thus, trip the bridged amp protection.
Once the amp is bridged, the "ground" will become live, not at 0 potential any more, so unlike normally driven amps, you can't have the "ground" from two channels be connected.

I'd use a piece of heatshrink tube and tighten it over the connector shell, or wrap it with a tape.

Also, please be careful with two bridged Vidars, as that is way over the specified power handling of headsets and Interface. It should be fine, just take care.
 
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Feb 15, 2020 at 6:29 PM Post #1,887 of 7,842
Yes. On mine they are both silver metal.

Today I switched all the electronics over to an isolation transformer with impeccable grounding and the issue is gone. Perhaps the outlet by my desk isn't grounded properly. Nonetheless, the fact that these are conductive is a strange one.
I think the issue will remain, because of amps being bridged, depending on the signal symmetry between left-right channel and on volume.
To me, it is very common that 3.5mm jacks with metal shell, the shell is a GND.

For the specified power handling, bridging amps is not necessary, so I wasn't thinking much about issues with bridged amps, sorry about that.
Anyhow, insulate them as I don't think the issue is gone by using ins. transformers.
 
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Feb 15, 2020 at 6:32 PM Post #1,888 of 7,842
What size resistors are used in the adapter box. They look like 2 watts but someone out there probably knows for real.
5WS, or 5 W small housing.
The resistor influence in sound is a discussions as old as hi-fi and I'm in the wrong camp to carry on discussing that.
 
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Feb 15, 2020 at 6:40 PM Post #1,890 of 7,842
I think the issue will remain, because of amps being bridged, depending on the signal symmetry between left-right channel and on volume.
To me, it is very common that 3.5mm jacks with metal shell, the shell is a GND.

For the specified power handling, bridging amps is not necessary, so I wasn't thinking much about issues with bridged amps, sorry about that.
Anyhow, insulate them as I don't think the issue is gone by using ins. transformers.
Thanks Aleksandar. The only reason I’m using two Vidars is so I can use the balanced interconnects between DAC and amp. I have some other amps on the way for review with the SR1a. Overall, fabulous product. Nothing like it.
 

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