Noise on Analog input on Pulsar

t.toth · Post by **t.toth** » Fri Jun 06, 2008 8:19 am

Hi anybody,

I have a Pulsar2 with Scope Fusion Platform 4.0 (balanced analog in with canons). When I activated and collegated the Pulsar2 Analog Source, on the channel of the STM 1632 mixer, comes right a little noise. As I record something the noise is there even if I don't use any hardware mixer on the input, but directly to the balanced inputs. When I disconnetc virtually the "Pulsar2 Analog Source" the noice goes away.

Could me anybody tell if there is a solution to record without noise? At the italian support I was told to send the soundboard to repear, but I can not be exist for 3-4 weeks without the soundboard.

If there is anything you can tell me, please post a help. Thanks.

Fede · Post by **Fede** » Fri Jun 06, 2008 8:48 am

How much is the noise?
If it is below -80dB is "perfectly" normal, as every analog input has a minimum noise floor. My scope card with balanced I/O has -85dB seen from the STM mixer.

cheers
Fede

t.toth · Post by **t.toth** » Fri Jun 06, 2008 9:44 am

Fede wrote:How much is the noise?
If it is below -80dB is "perfectly" normal, as every analog input has a minimum noise floor. My scope card with balanced I/O has -85dB seen from the STM mixer.

cheers
Fede

Thanks, but how can I look if it is 80 or 780 dB? I see only on the led the first leds below the fader are green.

Thomas

Fede · Post by **Fede** » Fri Jun 06, 2008 10:48 am

Also you may want to use "margin reset" button in the mixer to be sure to have an accurate measure.

cheers
Fede

Liquid Len · Post by **Liquid Len** » Sat Jun 07, 2008 10:36 am

ANY soundcard that does not have a 'breakout box' and requires you plug (analog) into a PC is noisy, at least in my experience. You probably don't want to hear this, but you might be better off doing the Analog-Digital conversion outside your computer, and piping it into the card digitally. There are a lot of cheap ways to do this, but you'll probably spend $100 at least. The Pulsar's analog inputs on my PC are so noisy I would probably never use them to record. (Well, I've never HAD to, yet...)

astroman · Post by **astroman** » Sat Jun 07, 2008 1:30 pm

actually the noise level on my Pulsar One and the external A16 connected via Adat is more or less identical
but the inside-PC-noise level may vary depending on the hardware you're running.
Pentium 4 was at least 3db more noise than P3 and CoreDuo

cheers, Tom

Post by **garyb** » Sat Jun 07, 2008 2:12 pm

t.toth wrote:
Fede wrote:How much is the noise?
If it is below -80dB is "perfectly" normal, as every analog input has a minimum noise floor. My scope card with balanced I/O has -85dB seen from the STM mixer.

cheers
Fede
Thanks, but how can I look if it is 80 or 780 dB? I see only on the led the first leds below the fader are green.

Thomas

that's normal.
ALL analog signals contain some noise. this is a complete non-issue.

chriskorff · Post by **chriskorff** » Sun Jun 08, 2008 1:45 am

Hello all!

I'm glad this has been brought up again - it's not something I worry about or lose sleep over, but I'm curious as to why the figure is -80dB...

I get the same figure when connecting an analogue input on the card or one if the inputs on my A16U - am I right in thinking that they're the basically same converter? The post above would seem to confirm this.

Anyway,

The dynamic range of the A-D conversion is given in the manual as 99dB (A weighted).

Is this disparity to do with the fact that the mixer is showing the broadband noise level, without any weighting curve?

Immanuel · Post by **Immanuel** » Sun Jun 08, 2008 1:55 am

It has likely a lot to do with the fact, that electricity is not as pure, as we would like it to be - not from the wall and not inside complex electrical equipment.

astroman · Post by **astroman** » Sun Jun 08, 2008 6:24 am

chriskorff wrote:...Anyway,
The dynamic range of the A-D conversion is given in the manual as 99dB (A weighted).
Is this disparity to do with the fact that the mixer is showing the broadband noise level, without any weighting curve?

as stardust and immanuel wrote - it's the real world values, not the marketing figures as typical specs pretend

Whenever I read specs of some gear, in particular the cheapos, I dunno if to LMAO or go vomit...
you know, that S/N 110 dB and more rubbish

usually they just seem take the 24bit theoretical range of the converter and pretend the output stage does a lossless playback of the very same.
I never re-calculated the figures, but I usually can hear those ultra-low noise levels effortlessly, which is a nogo by definition

cheers, Tom

tgstgs · Post by **tgstgs** » Tue Jun 10, 2008 11:29 pm

may i add an observation:
10 year old breakoutcable compared to new one on same board is a difference of 10dB in noise level;
where as 10 year old scopeboard shows no significant difference to new board with same cable;
----->
so its a good idea to buy a new cable now and then;
good vibes