too much ripple

steevo · 4th July 2007, 07:12 PM

I have built my regulated power using the LM337 and 317 and made the changes as suggested but still get about 1mv of ripple at the ouput. This also appears at the preamp supply pins even with onboard suppression and its appearing at the output as a low hum. The ripple occurs about evey 8ms. Is this the best that I am likely to get from these regulators. The ripple at the reg input is about 38mv pk-pk Has anyone had anything better from these.

Steevo

bigwill · 4th July 2007, 07:29 PM

NOTE: I am a newbie

How about pre-regulating?

steevo · 4th July 2007, 07:34 PM

I never thought of that, will it work.

Steevo

Nordic · 4th July 2007, 07:50 PM

If it is below 35V, search using preregulator as the search term and my Nic in the right box...

sawreyrw · 4th July 2007, 08:20 PM

1 mV of ripple is not worth worrying about.

steevo · 4th July 2007, 08:34 PM

1mv seems to have an effect on my preamp, the low level ripple is audible through my power amp when I cobbect it to my preamp. I thought the Ne5532 opamps PSRR would have taken care of 1mv but it doesnt seem to have. When I turn of the transformer the ripple and therefore the noise dissapear. Apparently because of the high gain inside the feedback loop they are very sensitive to noise.

Steevo

peranders · 4th July 2007, 08:57 PM

Steevo, have you hum with any load?

bigwill · 4th July 2007, 08:58 PM

Quote:

Originally posted by steevo
1mv seems to have an effect on my preamp, the low level ripple is audible through my power amp when I cobbect it to my preamp. I thought the Ne5532 opamps PSRR would have taken care of 1mv but it doesnt seem to have. When I turn of the transformer the ripple and therefore the noise dissapear. Apparently because of the high gain inside the feedback loop they are very sensitive to noise.

Steevo

Are you sure you don't have some kind of earth loop? Opamps are very good at rejecting supply noise

steevo · 4th July 2007, 09:34 PM

I could have an earth loop, not sure how i go about detecting where it is though.

Steevo

Leolabs · 5th July 2007, 02:32 AM

What's the size/value of the filtering caps???

4th July 2007, 07:12 PM	#1
steevo diyAudio Member Join Date: Sep 2005	too much ripple I have built my regulated power using the LM337 and 317 and made the changes as suggested but still get about 1mv of ripple at the ouput. This also appears at the preamp supply pins even with onboard suppression and its appearing at the output as a low hum. The ripple occurs about evey 8ms. Is this the best that I am likely to get from these regulators. The ripple at the reg input is about 38mv pk-pk Has anyone had anything better from these. Steevo

4th July 2007, 07:34 PM	#3
steevo diyAudio Member Join Date: Sep 2005	power supply I never thought of that, will it work. Steevo

4th July 2007, 08:34 PM	#6
steevo diyAudio Member Join Date: Sep 2005	ripple 1mv seems to have an effect on my preamp, the low level ripple is audible through my power amp when I cobbect it to my preamp. I thought the Ne5532 opamps PSRR would have taken care of 1mv but it doesnt seem to have. When I turn of the transformer the ripple and therefore the noise dissapear. Apparently because of the high gain inside the feedback loop they are very sensitive to noise. Steevo

4th July 2007, 08:57 PM	#7
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Steevo, have you hum with any load? __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

4th July 2007, 09:34 PM	#9
steevo diyAudio Member Join Date: Sep 2005	Regulator ripple I could have an earth loop, not sure how i go about detecting where it is though. Steevo


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4th July 2007, 07:29 PM	#2
bigwill General Nuisance diyAudio Member Join Date: Dec 2004 Location: UK	NOTE: I am a newbie How about pre-regulating?

4th July 2007, 07:50 PM	#4
Nordic diyAudio Member Join Date: Sep 2005	If it is below 35V, search using preregulator as the search term and my Nic in the right box...

4th July 2007, 08:20 PM	#5
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	1 mV of ripple is not worth worrying about.

5th July 2007, 02:32 AM	#10
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	What's the size/value of the filtering caps???

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