1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.

    Dismiss Notice


Discussion in 'High-end Audio Forum' started by magiccabbage, May 14, 2015.
872 873 874 875 876 877 878 879 880 881
883 884 885 886 887 888 889 890 891 892
  1. Triode User
    I am not saying that there are any differences in using the different pairs of the BNC inputs on Dave but I fear you are putting your head in the sand by pretending that there are not incremental improvements to be had by considering RF noise. Rob Watts himself is an advocate of reducing RF noise in the system. If you consider that his comments are based on unfounded speculation then so be it. Are you going to tell him or shall I?
  2. thomaskong78
    I had been using Dave and Mscaler with headphones for 3 weeks.

    As you recommended, I had tried cross feed 3.

    Wow what a difference!

    Now I will keep using it.

    Aslshark likes this.
  3. burbster
    Quick question for the forum, I am hoping to tap into your collective intelligence!!!

    I have a developed a ground loop hiss in my system which i have traced to my Dave. As soon as I connect the earth on the Dave the hum appears. The strange thing though, and what I wanted.opinions on, is when i use the xlr outputs there is no hum, as soon as i use the RCA the hum appears, on both left and right. It's not the cable as i have changed that. I am assuming an xlr cable does not connect Dave and amps chassis together? Any ideas how to get rid of this, is it a case of returning Dave for repair ? I could just use xlr but worrying I am just masking the problem.
  4. ecwl
    I have to admit I'm personally suspicious that the ground loop is not coming from DAVE as it is much more likely to be related to Aries or M-Scaler. And if you have a powered USB drive plugged into the Aries, it could be from that USB drive.

    First, I presume Aries, DAVE and M-Scaler and amplifiers are all plugged into your AQ Niagara. Because if one of these devices are not on the same power bar, you're already introducing a longer and potentially more problematic ground loop.

    The first thing I would suggest to confirm this is to unplug the M-Scaler and all extraneous cables (anything from M-scaler power and M-scaler to Aires and to DAVE). This is because even if a device is off, the loop can still be present sometimes. I would connect the Aries via Toslink to DAVE and then DAVE via RCA to your amp and see if you still hear the hum. If you don't, the hum is not from DAVE. Then I would connect Aries to DAVE via USB. If you hear the hum, then the ground issue is coming from Aries so you need to ground Aries. If you still don't hear the hum, I would connect Aries to M-Scaler via Toslink and M-Scaler to DAVE then to the amp via RCA. If you hear the hum, the issue is that you might need to ground M-Scaler. If you don't hear the hum, then go back to how you have everything connected (which I presume is Aries to M-Scaler via USB, the M-Scaler to DAVE then DAVE via RCA) and then issue is a ground loop probably from Aries to DAVE via the M-Scaler. For that, you either need to ground Aires or ground M-Scaler.

    To ground Aries or M-Scaler in the US/Canada, the easiest way is to ask your dealer to make you a thin cable with coax on one end and a speaker banana plug on the other end as you can simply plug the banana plug into the ground lead of the US/Canada Type A power outlet. The problem in Wales is that you use Type G outlet. So your dealer might need to connect the coax to a Type G power plug or you might want to buy iFi Groundhog+. Moreover, that power plug also needs to go into the AQ Niagara so that they're on the same ground circuit.

    My strong suspicion is that once you ground Aries or M-scaler, the hum would go away.
  5. rkt31
    Remove earth pin from mains power plug or connect all equipment to common earth. Removing earth can be a safety issue but eliminates ground loop. XLR by design cancels the noise.
  6. thomaskong78
    Another option is to use isolation transformer.

    It also clear up the sound in addition to solving ground hum issue.
    burbster likes this.
  7. burbster
    Thank you so much for the detailed response, and I probably should have been more detailed in my description of the problem. With everything fully disconnected and unplugged, with only the amp on and speakers connected there is no hum. Plug the RCA leads between amp and switched off DAVE, no hum, connect the earth pin on the supply to the Dave, then the hum starts. Mscaler and Aries and this point are unplugged and disconnected. (Incidentally I ditched my USB connection between Aries and MScaler, I found even the free optical cable sounded significantly better.)
  8. Triode User
    Hi, When you say you have "developed" a ground loop hiss", what do you mean by developed. Did it gradually come on or did you change anything? And you say hiss but also say hum elsewhere. Is it a hiss or a hum? Is it possible that the RCA cables are near some other mains cables and are picking the hum up from that?

    My first suspicion is that it is not the Dave and that the ground loop is elsewhere but it is odd that you did not have it before unless you changed something in the system.

    Oh, and please do not remove the earth from the power plug if you want to have a long life.
  9. burbster
    It is a hum not a hiss. I recently swapped out my RCA interconnects from the Dave to the power amp (using dave as a preamp) The cables were wonderful, but I started to hear this hum, at first only for the first 20 minutes or so, when everything warmed up it went quiet. But over the course of around a week it has become permanent and quite noticeable. I obviously thought it was the new cables, took them out tried XLRs no issues at all. Tried another set of RCAs and hum is there. I have now tried three sets of RCA cables all exact same hum so not the cable. I have just tried switching off everything in my house, I have a dedicated HiFi ring main, so I left that on, unplugged everything expect DAVE and power amp. Turn amp on with leads hanging out of back of amp, no hum. Connect leads to the dave, Off or On makes no difference, as long as its plugged in, the hum comes, on both channels at the same noise level. I am really struggling to figure it out. I am thinking there is something wrong with Dave single ended outputs. But then why do XLRs work, as they are taken from the single ended outputs through another output stage, so you would think that any fault would flow through to them as well??? May take dave back to dealer tomorrow to try it there.
  10. ecwl
    Yeah. That's very odd. It's either the amp or DAVE. Best to take it to your dealer to sort out.
  11. BassicScience
    Simple answer: RCA cables reference the signal to ground; XLR cables do not. If ground is at different levels between the connected components, the XLR won't care. The internals of how the balanced signal is generated are irrelevant. It is almost assuredly an issue with your A/C configuration as opposed to a problem with one of the components. Should be easy enough to experiment with different plugs, room, or building to verify that. FWIW.
    burbster likes this.
  12. adyc
    Are the amp and DAVE are plugged in the same power strip? If not, can you try that to see whether hum goes away? Please use normal consumer power strip not audiophile power conditioner.

    Sometimes it is not enough they are on the same circuit.
    Last edited: Jul 2, 2019
  13. burbster
    Yes tried them both in cheap 2 way extension lead, still there.
  14. burbster
    I was thinking about doing this, just need to understand how you earth the secondary side. In the UK isolating transformers are used domestically to feed bathroom shaver points, but the secondary is deliberately not earthed, the supply is floating to prevent a shock if you come in to contact with the live side of 220V. Not sure what the implications are of having a floating supply on hi fo equipment would be. So I suspect I would need to earth the secondary side separately, and create a new clean earth. ???
  15. adyc
    Ok. Can you try to disconnect the earth wire of the electrical plug of DAVE?
872 873 874 875 876 877 878 879 880 881
883 884 885 886 887 888 889 890 891 892

Share This Page