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EnergyConnoisseur c3, Denon x1400h, Tannoy center, Monitor Audio 3 , Infinity Beta sw12, rotel 1066
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Discussion Starter · #1 ·
A few weeks ago I bought a dac. And I connected it with the coax cable. I used a rca splitter to 2 rca's to 1 3.5mm audio jack, so -(rca) =(2rca) -(3.5mm).
But when i connect it to my amp using just simple rca's. I get a problem, the problem = that i hear i giant hum and hiss sound. also the volume is extremely low so i now have to bumb the volume knob all the way to get a bit of an accecteble level of music. Another problem is when i use the rca's i can only put them on halfway otherwise i get no sound. So what the f#ck is going on...

So is the dac just broken (in every way possible) or do i need to use a toslink to 3.5 mm? ( to connect my pc to the dac to the amp...)
 

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A few weeks ago I bought a dac. And I connected it with the coax cable. I used a rca splitter to 2 rca's to 1 3.5mm audio jack, so -(rca) =(2rca) -(3.5mm).

But when i connect it to my amp using just simple rca's. I get a problem, the problem = that i hear i giant hum and hiss sound.
Try plugging everything (computer, DAC, amps, TV, etc.) into the same power strip.

The hum you hear is often called a "ground loop". One of the most common causes is powering different audio devices from different wall power sockets. US homes have two incoming phases of power. If some audio equipment is plugged into one phase and some is plugged into the other, hum results. Another common cause is poorly grounded cable TV or satellite cable. Try unplugging from that.
also the volume is extremely low so i now have to bumb the volume knob all the way to get a bit of an accecteble level of music.
Another problem is when i use the rca's i can only put them on halfway otherwise i get no sound. So what the f#ck is going on...
These symptoms are both consistent with defective DAC construction, in particular the internal connections to its RCA sockets.
So is the dac just broken (in every way possible) or do i need to use a toslink to 3.5 mm? ( to connect my pc to the dac to the amp...)
An optical connection might help by avoiding the defective electrical connections, but I do think you should consider replacing the DAC as one of the things you do.
 

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EnergyConnoisseur c3, Denon x1400h, Tannoy center, Monitor Audio 3 , Infinity Beta sw12, rotel 1066
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Discussion Starter · #3 ·
thanks for the response i wil try a toslink and if that doesnt work i wil send it back to the company.
 

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Likely a ground loop, or bad/loose wire.

Could also be noise from the PC, or a mismatch between the DAC noisefloor and amp input sensitivity or gain,
but that seems less likely...

Ground loops occur whenever you have a conductive ground wire (pretty much every non-optical audio cable) between multiple devices which have ground pins (which is like: everything).
Sometimes you can get lucky, other times not. Just depends on how much AC line-noise is leaking between the hot AC wire and the chassis ground of any given pair of devices.

The noise leakage causes voltage or current to flow between the chassis's, and since audio systems use the ground as a signal reference, it is then modulated (mixed in) with the music signal, and then amplified to higher levels by the amplifiers. In extreme cases this can happen even when at idle or on ghost power.

Ground loops are almost exclusive to audio systems only. (Or at the very least... it is one of the FEW cases where it is directly user-noticeable/affecting. ;))


Optical is the simplest way to cure the problem, or using in-line RCA hum-eliminators.

The commercial solution is to star-wire or series-wire all of the safety/ground conductors in the audio equipment room. Typically done by radio stations, ham operators or recording studios. (You have to float the rack on insulators etc. It's not quick, simple, cheap or easy...)

The most common source of line-noise is cable tv boxes that are connected to the audio system via HDMI or RCA cables.
But literally anything has the potential to cause a ground loop without a star or series wired grounding system in place.

Sometimes adding a 2nd thicker cable between chassis screws can greatly reduce the hum by giving it a lower impedance path to take. Say from disc player to AVR or DAC to pre or pre to amp, or AVR to TV etc. Unlike star or series, there is no guarantee that paralleling will work for every possible groundloop scenario though...
 
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