First Lm3886 - Page 11

Stuey · 24th July 2009, 05:30 AM

...so the medical one is better for audio in hospitals.

pacificblue · 24th July 2009, 06:28 AM

Of course. The other must not be used there and no audio is bad audio.

infinia · 24th July 2009, 08:25 AM

Quote:

Originally posted by PJPro
Errr. Anyone know the difference between a standard and medical filtered module? They're about the same price. Is one better for audio?

Hospital grade means it has specs on low leakage currents returning to earth. So for them, they simply omit all the Y caps, since AC currents normally flow there. The non hospital grade actually filter much better. These filters are directional, so by adding your own extra Y caps is even better for filtering stuff from getting inside vs out.

compare diagrams page 12 http://www.schurter.ch/pdf/english/G...nformation.pdf

AndrewT · 24th July 2009, 11:00 AM

Infinia,
you forgot that some folk refuse to read.
Worse they expect to be spoon fed.

PJPro · 24th July 2009, 07:22 PM

I took a look at that data sheet last night, unfortunately before your post infinia. I was unable to arrive at the same conclusion as you....and went with the medical filters. These have now been shipped.

PJPro · 24th July 2009, 07:34 PM

Quote:

Originally posted by AndrewT
Infinia,
you forgot that some folk refuse to read.
Worse they expect to be spoon fed.

I'm really grateful for any help, advice or words of wisdom people are prepared to offer to help me through this first build. If people don't want to help, then please refrain from posting.

PJPro · 24th July 2009, 07:46 PM

Quote:

Originally posted by infinia

Hospital grade means it has specs on low leakage currents returning to earth. So for them, they simply omit all the Y caps, since AC currents normally flow there. The non hospital grade actually filter much better. These filters are directional, so by adding your own extra Y caps is even better for filtering stuff from getting inside vs out.

compare diagrams page 12 http://www.schurter.ch/pdf/english/G...nformation.pdf

You are saying that I can place a couple of caps from live and neutral to earth to replace these Y caps? I notice that the M80 variant of the medical filter is supplied with these caps.

If I were to replace the Y caps, how do I go about working out the capacitance required?

infinia · 24th July 2009, 08:09 PM

Depends on what frequencies you are trying to reject. More C is better until the case size gets to big and the SRF gets in the way. So start with 2200 pF and maybe more staying with that case size no bigger. Mount directly to output pins with the leads trimmed short etc.
Which part did you order? those IEC input filters are really expensive, I use usually scavenge whatever I come across.

PJPro · 24th July 2009, 08:12 PM

Am I gonna be able to get my faston connectors onto the lugs if I have caps soldered on?

infinia · 24th July 2009, 08:16 PM

You can work it out I'm sure, if not maybe you can try to change your order to get the right IEC filter part.

24th July 2009, 06:28 AM	#102
pacificblue diyAudio Member Join Date: May 2008	Of course. The other must not be used there and no audio is bad audio. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

24th July 2009, 11:00 AM	#104
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Infinia, you forgot that some folk refuse to read. Worse they expect to be spoon fed. __________________ regards Andrew T.

24th July 2009, 08:09 PM	#108
infinia diyAudio Member Join Date: May 2005 Location: Californication	Depends on what frequencies you are trying to reject. More C is better until the case size gets to big and the SRF gets in the way. So start with 2200 pF and maybe more staying with that case size no bigger. Mount directly to output pins with the leads trimmed short etc. Which part did you order? those IEC input filters are really expensive, I use usually scavenge whatever I come across. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

24th July 2009, 08:16 PM	#110
infinia diyAudio Member Join Date: May 2005 Location: Californication	You can work it out I'm sure, if not maybe you can try to change your order to get the right IEC filter part. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

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24th July 2009, 05:30 AM	#101
Stuey diyAudio Member Join Date: Mar 2006 Location: Perth, Western Australia	...so the medical one is better for audio in hospitals.

24th July 2009, 07:22 PM	#105
PJPro diyAudio Member Join Date: May 2009	I took a look at that data sheet last night, unfortunately before your post infinia. I was unable to arrive at the same conclusion as you....and went with the medical filters. These have now been shipped.

24th July 2009, 08:12 PM	#109
PJPro diyAudio Member Join Date: May 2009	Am I gonna be able to get my faston connectors onto the lugs if I have caps soldered on?

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