Directstream DAC - Hard to Believe?

Audio Components DACs
1

I’m sure this will get lots of people wondering. I have been chasing down unwanted sounds - took out the Conrad Johnson ET3+ and disconnected the USB. So all I have is the DAC with monoblocks. Usually works but with some noise. This time, with the USB disconnected, I start hearing a radio channel. So nothing connected and yet get radio? Do not understand!!! Help!!!

PS
But then I switched the DAC off, so all I have is the monoblocks feeding the Quad speakers… and the radio channel kept playing.!!!

2

I recommend trying balanced cables. The problem could also be those extra (ground?) wires attached to the chassis, you could try removing them.

3

It’s nothing $15,000 worth of power cables can’t fix.

4

Hi Ian.
Thanks for your ideas. The interconnects I’m using are http://www.mogamicable.com/category/bulk/microphone/quality_balanced/ earthed only at the DAC end. When I remove the shielding earth my noise floor jumps.

Colin

5

Could it be the fact that someone in a unit nearby is sending audio over their power cables? Not sure how that can relate back to receiving the audio and amplifying.

6

I suspect that’s a TV weather forecast rather than radio, for what it’s worth

7

Interesting. I use Mogami in my studio setup, and they are built very well. I’ve never seen that earthed wire before.

If you have any XLRs, you might try those. That’s my best guess. It’s also my understanding that the RCA outputs on the DS have a lower output level.

8

Hi sakabatou. It is an ABC radio channel in Australia where I live.
I disconnected the coax that leads to the TV not far away… Made no difference.

9

Hi @colb
Some wire is acting as an antenna which is picking up the audio. (ABC radio, could be worse as it could be a commercial shock jock broadcast ).
So it’s a question of disconnecting each cable in turn. I would also suggest trying the Mogami Studio XLRs - they only cost about AUD 80.00 from a band centre.
Are you using unshielded power cables?
Are the power and signal cables too close together/running parallel?

I have 2905s and once accidentally switched the power off to one speaker but I still heard great stereo for about 15min.

1 Like
10

Have you tried this same chain with another source/DAC?

11

I thought it sounded more like ABC24, but I guess it’s much of a muchness

12

Hi IanB52

I went looking for a shielded cable. The earth wire is a wire I connected to the shielding. There are lots of examples of people earthing one end of the shield to eliminate any induced currents.

XLR’s - I have Quad 2 Eighty monoblocks which only have RCA inputs. Are you suggesting I incorporate a XLR socket at the monoblock and run the ground wire from that to the ground on the monoblock and then use a XLR cable?

Shielded power cables - I am using the cables which came with all the equipment.
Colin

13

Hi IanB52.

When you say another source or DAC - the point I was trying to make was that there is no source connected to the DS and yet I have radio???

Colin

14

Hi Frank7036

That is what I thought - a wire acting as an antenna. But I thought you need more than an antenna to get sound out of the speakers. You would need the input of the antenna going to the amplifier. The only wires I have (excluding USB) is the shielded
interconnects to the Quad monoblocks and they are connected to the analogue RCA out’s. The earthing of the shield at one end could act as an antenna. So I do not understand how a signal picked up by the earthed shield of the mogami cables could get onto
the input side of the DAC?

Colin

15

Right. If you use another DAC with no USB then you can tell whether there is a problem with the DS.

If your amps only do RCA, then I wouldn’t worry about that.

16

Even speaker cables can act as antenna’s and inject EMI and RFI into your amplifier. This is part of the reason why speaker cables can affect the sound of a system. Though the non believers will tell you they all sound the same.

3 Likes
17

isn’t a minimum 3’ length of wire (acts like) an antenna?

18

I have never hear that one. I have heard that some manufacturers recommend at least 8 foot lengths on their speakers. I don’t remember who that was though.

19

No, a 5.8Ghz antenna is only ~12mm

20

Naim recommends a minimum on their own speaker cable, I believe.