252 -> RNHP strange headphone issue

I am using a Rupert Neve RNHP from my 252 for occasional headphone use.

Today I wanted to check how my Shure 535 in ears perform with it and it is acting quite odd. My other low impedance open back headphones perform wonderful, but the Shure (36 Ω) creates a strange birdlike noise when nothing is playing and when playing they sound very thin and strange.

Switching back to cheap Yamaha open backs (48 Ω) and the problem is gone.

Plugging the Shures in my iPhone and they sound great. I have the Shure since 2015 and it never gave me any issues, so I am wondering where the fault lies.

Any ideas are very welcome!

Potentially the 1/4" to 3.5mm adapter… you might try a few substitution tests to eliminate that.

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Odd, but worth a try later on. Thank you

I agree - but it’s the one thing that’s not common to both use cases. And stranger things have happened.

I have tried 4 different adapters and the problem persists. Also tried an av integrated amp here with adapter and that is dead silent as it should be.

The sound makes me think of a slipping conveyor belt. It might be dc or ground related, or the Naim amp hum coming through. The Shures are known to be quite sensitive. But considering the other headphones have a somewhat similar impedance, I am a bit puzzled.

Can you patch the output of the iPhone into the Neve? That would eliminate the 252.

Good ideas. I took the Neve out of the system, placed it on the kitchen counter and plugged in the headphones with an iphone input. Same thing, silent on the yamaha, cidadas on the Shure.

Took the iPhone out and the Shure is still making the sound on all three (non input) channels.

The two strange things that remain:

  • RNHP works well with the Yamaha, dead silent.
  • The Shure works well on different sources, my computer, iPhones, iPad.

It’s the Rupert Neve unfortunately.

I tested a third pair of headphones and the noise is there. Somewhat less present, but there nonetheless. I suppose the Shures are very sensitive indeed, the cheap Yamaha’s aren’t at all and the last pair are in between.

Off to find a repair for the RNHP.

On the brighter side - it wasn’t the 252…

Good luck :slightly_smiling_face:

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Agreed!! Thanks

For future reference of anyone running into this issue. Rupert Neve’s support suggested I swap the adapter to Phihong PSA15R-240P6. I did and the issue is resolved.

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