Hi all,
I would like to ask for the question on the regulator which is low noise for the clock circuit!
* Beside the LT323, LM1085, any good circuit is better than their performance?
Please advise! The input voltage for about 9-27V somthing....
Thanks a lot~
I would like to ask for the question on the regulator which is low noise for the clock circuit!
* Beside the LT323, LM1085, any good circuit is better than their performance?
Please advise! The input voltage for about 9-27V somthing....
Thanks a lot~
Hi,
Do you want to use SMPS instead of using Linear SMPS.
The OSC is 100KHz. What OSC you have, I can tune the OSC in SMPS to not overlap in the harmonic.
Email me.
50140834@alumni.cityu.edu.hk
I have demo board, try, I also want to know the result.
Regards,
nFORCE
Do you want to use SMPS instead of using Linear SMPS.
The OSC is 100KHz. What OSC you have, I can tune the OSC in SMPS to not overlap in the harmonic.
Email me.
50140834@alumni.cityu.edu.hk
I have demo board, try, I also want to know the result.
Regards,
nFORCE
nFORCE said:
gents
Be carefull with switching regulators, they are noisy, and when I say noisy I mean they produce a sh%tload of wideband noise which may unpleasantly interfere with your oscillator.
My own low noise supply that I commercially sell exhibits less than 5nV/Sqrrt Hz in the range of 20 Hz to 100kHz
For your reference: An average LM317 is 30 dB more noisy......
all the best
Fully agree with Guido. A well build discrete linear regulator is unsurpassed regarding noise. PSU noise is damn important for powering an oscillator that is intended to be of lowest side band noise and hence jitter.
Why would anyone use a switch mode regulator for powering such sensitive electronics? Even mechanical noise can largely impact performance of an XCO.
Why would anyone use a switch mode regulator for powering such sensitive electronics? Even mechanical noise can largely impact performance of an XCO.
Tazo said:
Never think, just be sure !
My TL431 datsheet says: Low noise.........
Few, that is low !
I'd have to measure on the unit but I would be very surprised if it is below 20 nV Sqrrt Hz.
succes
According to my measurements......
Assuming that they didn't lie to me:
An unbypassed LM317 has noise in the range of 3 uV/sqrt-Hz.
The simple supply in the oscillator schematic I posted is around 4 nV/sqrt-Hz.
Jocko
Assuming that they didn't lie to me:
An unbypassed LM317 has noise in the range of 3 uV/sqrt-Hz.
The simple supply in the oscillator schematic I posted is around 4 nV/sqrt-Hz.
Jocko
Try this....
Run the oscillator of a battery supply.......... you will be amazed! Nuff said.
Jam
P.S. This is probably the only time I wowld use a battery supply.
Run the oscillator of a battery supply.......... you will be amazed! Nuff said.
Jam
P.S. This is probably the only time I wowld use a battery supply.
Not even batteries
The benefits to battery PSU's I suspect come from overcoming the earthing / 50(60) Hz noise prevalant in bad designs.
Noise levels are little better than even an LM317 at LF though - although they are better at HF.
Subjective audibility of jitter spectra is the relevant factor here, I suspect - start to draw current and batteries look appaling.
Andy.
P.S. TL431's are noisier than 317's and offer far worse impedance characteristics. Used as a filtered reference though they are good.
The benefits to battery PSU's I suspect come from overcoming the earthing / 50(60) Hz noise prevalant in bad designs.
Noise levels are little better than even an LM317 at LF though - although they are better at HF.
Subjective audibility of jitter spectra is the relevant factor here, I suspect - start to draw current and batteries look appaling.
Andy.
P.S. TL431's are noisier than 317's and offer far worse impedance characteristics. Used as a filtered reference though they are good.
The benefits to battery PSU's I suspect come from
Go Andy Go! Making the world a better place through low noise voltage supplies the old fasion way, by actual measuring them.
Go Andy Go! Making the world a better place through low noise voltage supplies the old fasion way, by actual measuring them.
Ehm, no idea what you are trying to say Fred 
For those of you struggling with PSU noise, get rid of it in the oscillator circuit itself as well. Attached a circuit that does. T1 is also acting as an extra PSU filter as well. For 256 x Fs, L1 can be a 10.7 MHz mf-transformer, for 512 x Fs it can be a 27 MHz transformer. I am up to building this. In the past I build similar ones with a dual gate mosfet.
For those of you struggling with PSU noise, get rid of it in the oscillator circuit itself as well. Attached a circuit that does. T1 is also acting as an extra PSU filter as well. For 256 x Fs, L1 can be a 10.7 MHz mf-transformer, for 512 x Fs it can be a 27 MHz transformer. I am up to building this. In the past I build similar ones with a dual gate mosfet.
Attachments
Andy,
You are right the 60/50 Hz component is important but I suggest you try the experiment, it is pretty simple to implement, then I would suggest you look at the jitter spectra and develop some correlation to what you hear. I was skeptical about the battery idea till I heard it.
All I am saying is keep an open mind till you have tried it. On the other hand no one has convinced me yet that a battery supply is better for an amplifier compared to a correctly designed traditional supply.
Jam
P.S. Any thoughts Fred?
You are right the 60/50 Hz component is important but I suggest you try the experiment, it is pretty simple to implement, then I would suggest you look at the jitter spectra and develop some correlation to what you hear. I was skeptical about the battery idea till I heard it.
All I am saying is keep an open mind till you have tried it. On the other hand no one has convinced me yet that a battery supply is better for an amplifier compared to a correctly designed traditional supply.
Jam
P.S. Any thoughts Fred?
Jam
I have no doubt you're right in your experiences, but I know you can get better results with a well-designed PSU, which can be dramatically quieter than batteries, under steady state and dynamic conditions.
Maybe not so easy though 😉
A.
I have no doubt you're right in your experiences, but I know you can get better results with a well-designed PSU, which can be dramatically quieter than batteries, under steady state and dynamic conditions.
Maybe not so easy though 😉
A.
Andy,
Well I hope you succeed and please share the results with us as I am no big fan of batteries except in non-audio related products.............😀
Jam
Well I hope you succeed and please share the results with us as I am no big fan of batteries except in non-audio related products.............😀
Jam
If I get time...
...I'll post some FFT plots of battery noise vs a low noise regulator at the weekend.
Andy.
...I'll post some FFT plots of battery noise vs a low noise regulator at the weekend.
Andy.
Plots
Hi ALW,
I would be <B>MUCH</B> more interested in listening results with both types of regulators feeding a masterclock in a CDP.😉
Hi ALW,
I would be <B>MUCH</B> more interested in listening results with both types of regulators feeding a masterclock in a CDP.😉
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