Pink Noise generator

Status
Not open for further replies.
Jump to Latest
Lyra

Lyra

Member
Joined 2003
#1
Hi 🙂
I don't know if this is the right place for this but I'll give it a try...

I have been looking around the web for information on a Phantom Powered Pink Noise generator, but so far the only thing I can find is ready made equipment.
thought I might try to come up with something on "my own" then.
Found a pink noise generator described on http://sound.westhost.com/ , mixed with a phantom power "PSU" found another place, and added a SSM2142 and came up with this (attached) schematic.

What's bother me a little is that the SSM2142 is needing a differential power supply, while the OP-amp doesn't.
I don't think this should be a big problem as long as the parts is ac-coupled, but I might be proven wrong here.

Decided that I should ask You...before I actually build this one...does this look OK to You ?
...or am I way out here ??

The two 0-ohms resistor is there of one reson only...they make the layout a little bit easier to route on a single side board (are using Eagle)
The SSM2142 is chosen over a transformer of one reason only...cost.
The TL072P is chosen because this was the OP-amp chosen in the original P.N.G., and this thing is meant to make noise, so I don't need a high priced Low Noise OP-amp here !

There also might come in handy to have some kind of gain control between the OP-amps and the balanced line driver !?, but this could be implemented very easy a little later.

Regards
Lyra


Sorry, but the format of the drawing made me attach a zip-file...I had problems making it small enough...
 

Attachments

#3
davidsrsb said:
Digital approaches are far more predictable and can be cheap these days.
Click to expand...

Have tried one of this, and don't like it. There was something strange with the sound it produced. Just like "something" was somehow rumbling back and fourth...coming an going !?
Difficult to explain...😕

...and pink noise generators are easy to come by, but I want a small unit that is powered via phantom power delivered by the audio mixer...and theese are not so common...they do exist, but haven't found any with a reasonable price tag yet.

Lyra
 
#4
Digital noise generators always have a repetition rate which must be long enough to avoid low frequency artifacts. Once you meet this point, the performance is nearer ideal than most analogue methods. The latter have problems with rising noise levels at low frequencies and bursty shot noise.
 
#7
davidsrsb said:
The second one is 25 stages so, if the tapping is correct, the sequence is (2^25) - 1 or 33.5E6, which is long enough. The output spectrum is white modified with a sinx/x curve, so 25KHz clock is far too low - 100KHz is minimum.

I think that the 4006 is long obsolete.

There is a tool at http://www.eecircle.com/applets/009/LFSR.html for finding the tap points.
Click to expand...

I'm afraid You lost me there 😕 ....
...but will the old Elektor noise generator (attached) be good enough ?
(thanks to moamps for sharing this...!)

Lyra
 

Attachments

  • pink_noise_thumb.jpg
    pink_noise_thumb.jpg
    2.8 KB · Views: 440
#9
davidsrsb said:
....I don't know if the pinking filter is correct.
Click to expand...


It looks loke some kind of older passive filterdesign.
I may be better of if replacing the filter with the one from westhost ?
Think that one at least is decent "pink"...!?

I may also be better off if replacing the "original" SSM2142 with some OP-amps...:xeye:

Lyra
 
Status
Not open for further replies.
Top Bottom