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2x4HD / DDRC-24 noise - tweeter hiss 2 years 4 days ago #58009

  • vince.rogier
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Hi,

Creating this topic as I could'nt find any existing ones with same issue/use cases or any solutions.
I have a 2x4HD upgraded to DDRC-24 but the issue existed prior the upgrade.
Here is my configuration

Inputs are:
- Toslink input is Bluesound Node2i
- Analog input is Marantz AVR front preouts (not important here)
- USB input is only used time to time for REW measurements (not important here)

Outputs are:
- 1 & 2 => power amp (hypex nc252mp, 25.5db gain) using RCA/XLR cables (wired properly)
- 3 => subwoofer

Regarding DSP capabilities, I only use Dirac and XO filters for sub integration.
Input and outputs levels are 0db.
My speakers have a sensitivity of 94db.

Volume control is done are source level.

I have a hiss in my speaker tweeters that is not audible at listening position but that is noticeable when being closer to the speakers.
Feeding the power amp with the minidsp (input is toslink) , the hiss is audible up to 1 meter!
Feeding the power amp with the node 2i directly (input is RCA), the hiss is much weaker and only audible at about 20-30 centimeters.

The hiss is not dependent on the source volume.
And when I disconnect the minidsp from the power amp, my tweeters are dead silent !!
But as soon I connect the mindsp to the power amp, even with all inputs disconnected, I get that hiss that you can hear to 1 meter.
Disabling Dirac and XO filters (minidsp doing nothing) => I get same hiss.
By hiss, I mean white noise.

Any clue ?

Regards,

Vincent
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2x4HD / DDRC-24 noise - tweeter hiss 2 years 4 days ago #58022

  • vince.rogier
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Muting the unit makes the hiss/white noise to disappear - speakers are dead silent.

I am also experiencing crack/plocs noises when changing presets or loading configuration to the unit.

Any workaround ?

Regards

Vincent
 

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2x4HD / DDRC-24 noise - tweeter hiss 2 years 4 days ago #58023

  • Ultrasonic
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I'd suggest you contact support to try to establish whether your unit has a fault or not. 

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2x4HD / DDRC-24 noise - tweeter hiss 2 years 4 days ago #58024

  • vince.rogier
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That's what I ended up doing :)
Now, Waiting for their reply.

 

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2x4HD / DDRC-24 noise - tweeter hiss 2 years 4 days ago #58029

  • krkalino67
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I have the same issue. Seems to be common with the DDRC-24 and the 2 x 4. I had to attenuate my amp to reduce as I listen nearfield. Surprisingly,  my speakers are very inefficient as well. Contemplated upgrading to the SHD for the better DAC, better specs, balanced in and outs, BUT don't need preamp capability or streaming. Shame the product is flawed. Support will tell you that it's your gain structure. Unit just measures poorly. 

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2x4HD / DDRC-24 noise - tweeter hiss 1 year 11 months ago #58225

  • mdsimon2
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It definitely IS a gain structure issue. The 2X4HD is a great product but it is certainly not spec'd as low noise. What do you think happens when you start with a DAC with 103 dB dynamic range at 2 V (presumably A weighted) and send it through 26 dB of amplifier gain? You get hiss. 

SHD has a measured dynamic range of 116 dB at 4 V which is significantly better than the 2X4HD. Remember all noise from your DAC will be multiplied by your amplifier so a low noise DAC (and a low gain amplifier) is more important than it may appear at first glance.

Michael

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2x4HD / DDRC-24 noise - tweeter hiss 1 year 11 months ago #58271

  • Jeronimusch
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Yes, I've had similar issues and attenuate the output of the minidsp with Rothwell in line plugs to address this. The output impedence is on the high side, 560 ohm, when plugged into a power amp this doesn't help. (the new flex is 200 ohm).
I've found that the minidsp best is used as a source. I have a multichannel preamp after my 4x10 for a active stereo 3 way. Another route would be using a buffer stage which I'm looking into at the moment. This will solve the impedence issue but I'll take the new flex as the numbers look very good... 

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2x4HD / DDRC-24 noise - tweeter hiss 9 months 3 weeks ago #64330

  • waldrandhamster
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I have /had the same issue. The signal comes from my Atoll MS120 to DDRC via optical and then goes from the DDRC24 to my Atoll MA100 via cinch. I had a small but recognizable hiss and some humm. What helped me here was, to put my 2 Rothwell Attentuators between the cinch cable and the amplifier. Now the hiss are hearable when you are very near to the speakers. And that works for me....:-).

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2x4HD / DDRC-24 noise - tweeter hiss 9 months 3 weeks ago #64332

  • vince.rogier
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Hi,

I ended up last year in getting a flex unbalanced.
Hiss completely gone :)
​​​
Regards,

Vincent 
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2x4HD / DDRC-24 noise - tweeter hiss 9 months 2 weeks ago #64347

  • itskaefer
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You can try to use a better power supply. That helped a bit on my unit. But the hiss was still there.
miniDSP SHD, Marantz SA7001Ki, Rega P1
2x XTZ Edge a2-300 monoblocks - nuJubilee 45 bookshelf
Custom ICEPower 250ASX2 BTL - Hertz ES300 custom sub

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