What about noise ... (BD-Design)
by PeterSt. 
, Netherlands, Saturday, February 02, 2008, 12:01 (5922 days ago)
Hi,
Talking about earthing problems and all, I wondered whether someone knows what to do about (more or less) white noise. I mean, is this something which could be attacked by general means like shielding, better impedance match, etc., or would it be an inherited property of the device producing it ?
In my case it's an add up of, say, PC, Fireface and TwinDAC+ and each device (including connection !) adds its own noise. The end result is a very much audible noise (through the Orphean) at even 12m distance when music is not playing. And obviously I'm sure it influences SQ.
Note that there is no pre-amp in the path at judging this, and what goes with that is that nothing is attenuated.
Another related question would be what the spec of a DAC actually tells, when it says that the SNR is 96dB which most obviously is about the digital path only. So how would the analogue noise be expressed with such a device ? it is clear to me that at 96dB attenuation some of the left 1 bit resolution music can be heard, but if there's one reason the music caNot be heard it would be the analogue noise, that being several times louder.
Thank you,
Peter
PS: the only thing what bugs me is noise, not a spur of hum.
For Bert : this is not about the clicking noises and it is not about the "light dimmer" noise. It's fairly white noise.
What about noise ...
by PeterSt. , Netherlands, Saturday, February 02, 2008, 13:43 (5922 days ago) @ PeterSt.
Actually I found the largest source of noise ...
I used a general mixer setting in the Fireface, allowing for all devices to output. Now I allow only SPDIF.
So beware, because apparently all those (digital) outputs add up noise as well. No matter they are not connected.
Btw, I tried the internal HDEF Audio Device (SPDIF) of the mobo as well. Low noise but bweh sound.
What about noise ...
by Flecko , Wednesday, February 06, 2008, 22:14 (5917 days ago) @ PeterSt.
Hi Peter,
last week I had an amplifer for trial listening at home and although I didn't kept it I must say the nois was ultra low. With my Ciare HX201 in Berts Oris150 (about 103dB) I realy heard absolutly nothing even if I held my ears directly to the speaker. This was the case if I turn down my poti. When I turn it up at 50% appears a audible noise wich was hearable directly at the speaker but not bothering at all when I listen to music. Do you use a poti or transfomer or do you control the volume digital? If the last is the case you can get down your noise by using a poti or transformer(I say this, although I guess you know it). Another source of noise, if your amp is quiet, could be the power source of your dac. The batteries produces also a (perhaps realy tiny)noise wich can be short cutted by placing a small capacitor parallel. I used a small elko and a glimmercap. The values were optimised by Mr. Hartwig(THEL) but I don't remember it :(. If you like to try I can look next time when I open my dac (will be soon).
That the digital source is responsible for the noise you and me are hearing is of course a good point. I never thought about this, but as you tell (and prove) , it is absolutely reasonable. I mean our digital sources are, compared to the rest of the chain, "low cost" equipment. But there is nothiGCg on the market to do I better.
Greetings Adrian
What about noise ...
by PeterSt. , Netherlands, Sunday, February 17, 2008, 14:26 (5907 days ago) @ Flecko
Adrian, Eddie too, thank you both for your responses.
Do you use a poti or transfomer or do you control the volume digital? If
the last is the case you can get down your noise by using a poti or
transformer(I say this, although I guess you know it).
As is clear by now on my own (GC) forum, this all was about going to digital volume control (and it was a transformer beefore). By now the noise is near zero with a couple of CrazyA's as main amps, the TwinDAC+ as DAC and the Orpheans with around 115dB sensitivity. The Fireface is in between as well.
As explained the many "ports" open at the Fireface800 added up a lot of noise, but the transformer added its portion as well.
Now I'm rid of the noise it's quite unbelieveable how -as I can recognize now- can hear that noise right through (better : in) the music, once it is there again. And I don't refer to the blazing noise I mentioned in this first post, but just with transformer attenuated sound, providing noise I could hear from, say, 20 cm distance from the speaker (no music playing).
As I see it now, the noise just adds up to the music, or anyway does something to it.
Again, thanks,
Peter
What about noise ...
by Bert , Sunday, February 17, 2008, 14:41 (5907 days ago) @ PeterSt.
Peter,
As explained the many "ports" open at the Fireface800 added up a lot of
noise, but the transformer added its portion as well.
Are you sure it was just the transformers? Or was it due to the extra cabling and picking up noise from somewhere else?
I do not hear any difference in noise with the CrazyV connected or going directly to the CrazyA's, all is super silent here (earth gives no problem anymore and ground does not pick up anything just the same...) 
Bert
--
BD-Design - Only the Best!
What about noise ...
by PeterSt. , Netherlands, Sunday, February 17, 2008, 22:13 (5906 days ago) @ Bert
Are you sure it was just the transformers? Or was it due to the extra
cabling and picking up noise from somewhere else?
Hi Bert,
I think I am, yes.
But think of it. What would be the extra / other cabling when you move out the transformer ?
Also, think of what one hears on noise matters like the last time we both listened to it ... we couldn't agree much on "light dimmer" noise, and only did on strange clicks. Apart from some white (?) noise those clicks are coming from the transformer. Don't ask me how or why.
I do not hear any difference in noise with the CrazyV connected or going
directly to the CrazyA's, all is super silent here (earth gives no problem
anymore and ground does not pick up anything just the same...)
I sure believe you. Anyway I did not hear as few noise I have here now, from your speakers. But this was earlier and things will have changed.
Well, in my last post I only wanted to emphasize the importance of inaudible noise from a fair distance, because I now think it's just audible in the music. Not as noise, but as an influence ...
Peter
What about noise ...
by Bert , Sunday, February 17, 2008, 22:24 (5906 days ago) @ PeterSt.
Hi Peter,
But think of it. What would be the extra / other cabling when you move out
the transformer ?
Impedance issues? You use pretty long cables from the TVC's to the CrazyA's and that is usually not a good thing. This way the cable behind the TVC becomes a kind of antenna and the "drive" in the sound is much less. You need current (active pre-amp) to drive long cables.
I tried to explain that a while ago...just try very short cables and long speaker cables in combination with the TVC... there will be a major difference only by that change...
Well, in my last post I only wanted to emphasize the importance of
inaudible noise from a fair distance, because I now think it's just
audible in the music. Not as noise, but as an influence ...
Yes, it is influencing a lot, the more "noise" the less smaller details will become audible....not what you mean though but still. :wink:
Bert
--
BD-Design - Only the Best!
What about noise ...
by PeterSt. , Netherlands, Sunday, February 17, 2008, 22:58 (5906 days ago) @ Bert
But think of it. What would be the extra / other cabling when you move
out
the transformer ?
Impedance issues? You use pretty long cables from the TVC's to the
CrazyA's and that is usually not a good thing. This way the cable behind
the TVC becomes a kind of antenna and the "drive" in the sound is much
less. You need current (active pre-amp) to drive long cables.I tried to explain that a while ago...just try very short cables and long
speaker cables in combination with the TVC... there will be a major
difference only by that change...
Well Bert, I don't want to start a discussion, so I do ... a little ...
In fact this is an interesting subject, knowing what longer loudspeaker cables do measured to sound. I only want to say : this is not an easy comparison. But looking at the TVC of course you are right. This tells me though : how difficult is a TVC in the end (net) ? It is much "requiering" ...
Also you'll know that an active pre-amp adds even more noise (and baddies).
Currently I joined the leage of "no pre-amp". You know I was aiming for that, and "today" I succeeded. Let's please conclude with this, just because I want to have it off my chest :
Although you may never have perceived the merits of it, I LOVE your TwinDAC+ for its 18 bits capability. That I had to exploit it myself doesn't do any less justice to the fact it just has those merits. I bought it for that (:yes
and today I use it. Just recall my very first questions about it and you know I don't make it up.
Is this related to this thread ? yes, all over.
Btw, you know who I want to thank really. Please do it on behalf of me. I'm serious.
:heart: :heart: :heart:
Peter
What about noise ...
by Bert , Sunday, February 17, 2008, 23:06 (5906 days ago) @ PeterSt.
Hi Peter,
Btw, you know who I want to thank really. Please do it on behalf of me. I'm serious. :heart: :heart: :heart:
Done... :wink:
Bert
--
BD-Design - Only the Best!
What about noise ...
by Eddie , Saturday, February 02, 2008, 21:37 (5921 days ago) @ PeterSt.
Hello Peter,
Noise is inherent to the materials used in electronics, especially semiconductors and resistors. Opamps often have low-noise versions at higher price. Further, e.g. carbon resistors are known to be quite noisy. As far as I know, nothing can be done about this.
On the other hand, equipment can be made really low-noise. I once red that there is a fundamental limit for analog amplifiers at ~21-22 bits resolution, that is ~130 dB S/N-ratio. That should be good enough for anybody's ears.
You can find some more info on http://en.wikipedia.org/wiki/Electronic_noise .
Kind regards,
Eddie