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TOPIC: external power supply for dsp to reduce hiss

external power supply for dsp to reduce hiss 8 months 4 weeks ago #24026

  • Actimel
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Hello,

i got a low hiss on the pwr ice 125.

Is it possible that this noise is coming from the auxiliary power supply at the ice module?
Has already someone try to supply the dsp module from a external power supply or to improve the the auxiliary power supply?

The input signal should be clean and out of hiss (ASE EBU from DDRC)

2.3.6 Amplifier jumper pads
The PWR-ICE125 features an amplifier module with “symmetric” output level. In most 2 way situations (e.g. 2way box with sensitive HF
frequency), the high frequency would typically only require a fraction of the power of the low frequency driver. While the level could
be adjusted inside the DSP, we added an analog pad on the board to “pad” the analog signal instead. See below jumper and state
for more information. By default, all jumpers will be closed (0dB and no attenuation)

Open 0dB / No attenuation.
Closed -16dB
will this settings also work in my case?

any advices are welcome :)
Best regards Paul
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external power supply for dsp to reduce hiss 8 months 3 weeks ago #24055

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Hi,
my writing are wrong it is different way
Open -16dB
Closed 0dB No attenuation
the hiss is gone and the sound is outstanding

however on one Speaker i can hear now a soft whistle have someone else ever detect this noise?
what can i do against it?


regards Paul
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external power supply for dsp to reduce hiss 8 months 3 weeks ago #24116

  • devteam
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@ Paul

The padding for a high frequency is indeed possibly required in some cases (e.g. best to pad analog than digital).
What do you mean by soft whistle? Are all amps correctly "earthed?

DevTeam
MiniDSP, building a DIY DSP community one board at a time.
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external power supply for dsp to reduce hiss 8 months 3 weeks ago #24137

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Hi,

thanks for replay

I got sensitive speaker about 94db so minus 16 db in gain is not a issue it is more an advantage because i can run the digital path on higher sound level.

It sounds like someone is breathing through the teeth.

however if i am back home i will check the earth the modules are not on the same socket.

i will report

Best regards Paul
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external power supply for dsp to reduce hiss 8 months 3 weeks ago #24175

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Hi,

if i connect the modul same way and the same power plug as the other there is still the whistle.
It is hear able as soon I power it up just a different frequency in the beginning.


how you want me to check the earth on the modules?
or any other advice?

Best regards Paul
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external power supply for dsp to reduce hiss 8 months 3 weeks ago #24182

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Goooood Morning,

I guess I found the reason please check the attached picture.

I unscrued all blugs and on one I could see a very well done soldering of the GND ;)

My thinking is that if the plughousing was scrued on the GND hits the plughousing.

Does this explain a strange sound? Like a whistle, zip?



However the sound is outstanding and the dsp possibilities are awesome.

Best regards Paul

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external power supply for dsp to reduce hiss 8 months 3 weeks ago #24235

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Paul

Worth investigating indeed!You can use a simple strap to do the test.

Keep us updated and glad to hear that you're having fun with the DSP. :-)

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