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USB Audio Interface to Drive Neumann KH750/KH80

MiCoHi

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Currently running the above speaker combo driven by a RasPi Roon endpoint which feeds into a Topping D10s as a listening room setup.

Wanting to run the Neumann MA1 on the system, so will need a simple USB audio interface for the calibration and will probably leave the interface installed afterward. I've tried a Behringer 404HD interface, but it wouldn't go loud enough to satisfy the Neumann software - even with the gain at max on the 404HD (and the mix knob fully on DAW as opposed to input), there was still a 7.5dB deficit being reported. Probably something to do with the pseudo-balanced outputs on the Behringer. It was being powered by the switch mode supply too, not just bus power.

Would something like the MotU M4 do the trick? Has it a beefier output via the main outs (which are properly balanced I believe)? If not, what's a good USB audio interface that is capable of adequate balanced output levels, sufficient to drive the MA1? Looking at things like SSL 2+ even the RME Babyface if need be (I run an RME ADI 2 DAC as my headphone listening station and love it).

Appreciate your thoughts in advance and thanks for the wealth of info on these pages.
 
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radix

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I have the exact same problem. I drive the KH750/KH80 via spdif from a Mac with a usb/spdif converter (Douk Audio).

I would have thought the 404HD would work. Did you turn on the 48V phantom for the mic?

I broken down and bought a Scarlett Solo to do the calibration. It should be arriving today. You can ebay them for about $60-$80, or new they are $120. You need 1/4" TRS to XLR cables.

Marc
 

MenloBob

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I'd get a M4 and use it as the DAC as well and find another use for the D10s. It has great balanced outputs for those Neumanns. And a pretty transparent volume knob.
 
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MiCoHi

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I’ve ordered the M4 - no Uk stock at the moment so a small wait of around 10 days I’m told. The D10s feeds the Neumanns perfectly well and via unbalanced phono jacks too, so I was very surprised that the Behringer didn’t work.
I have the exact same problem. I drive the KH750/KH80 via spdif from a Mac with a usb/spdif converter (Douk Audio).

I would have thought the 404HD would work. Did you turn on the 48V phantom for the mic?

I broken down and bought a Scarlett Solo to do the calibration. It should be arriving today. You can ebay them for about $60-$80, or new they are $120. You need 1/4" TRS to XLR cables.

Marc
Yes, phantom was on and there was plenty enough gain to cause feedback when the mix knob was anywhere other than 100% USB.
I was using the xlr outs, straight to the KH750 ins using balanced star quad cables. At first, the MA1 software just said the output from the audio interface was too low. On turning the main monitor gain up, it settled at 7.5dB too low, so I can only assume it’s something to do with the impedance balancing at the 404HD outputs.
Roll on the arrival of the M4.
 
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MiCoHi

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PS, I’ll be making up my own 1/4” TRS jack to xlr cables - all Neutrik and wired as ground, hot & cold on pins 1,2 & 3.
 
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MiCoHi

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Screenshot 2021-08-26 at 22.25.34.png

Possibly just found out why the 404HD had issues - the manual states max output as +3dBu - that's only 3.1V peak to peak, whereas the M4 is rated at +16dBu or 13.8V peak to peak - a huge difference.

You pays your money etc!!
 

radix

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Ok, glad you figured it out. The Scarlett Solo says it has +15 dBu balanced line out, so I should be ok once it arrives.
 
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MiCoHi

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Yes, you should be fine. I've just read the updated review of the 204HD by Amir and the output doesn't even get up to the lacklustre specs it seems. Pity as the overall feel of the Behringer is pretty good and I wanted to like it as a little underdog interface.
 

3125b

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The KH 750 is specced for up to +24dBu (12.3Vrms resp. 34.7Vpp) input level, like most pro gear would be.
My RME for example has four level settings, 4,13,19 and 24dBu.

+3dBu on that Behringer is really low though, I never actually noticed that, seems important because not much modern gear would get to full output with only 1Vrms balanced input. Thanks for pointing it out.
 

radix

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I just finished doing the calibration with the Scarlett Solo. Worked just fine. Glad I had a metric tape measure.
 
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MiCoHi

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Calibration complete with a Scarlett 18i20 and a laser measure plus mic stand. Sounding scarily good now, even at well off axis and beyond Neumann’s recommended distances.
 
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