optocoupler to eliminate ground loop

ostie01 · 13th March 2006, 05:34 AM

Hi, would like to know if it's possible to eliminate ground loop problem
with optocoupler or can it be used in amplifier input.Are they stable enough. Can I use this device to transfert analog signal like in audio circuit. Thanks everybody for your time.
.

Upupa Epops · 13th March 2006, 06:09 AM

Look at datasheets of CP Clare....

peranders · 13th March 2006, 06:49 AM

There are analog optocouplers but the quality isn't enough for audio I'm afraid. Check for instance IL300 from Vishay. I have used it in a 4-20mA loop and for this purpose it's OK.

http://www.vishay.com/optocouplers/list/product-83622/

davidsrsb · 13th March 2006, 06:52 AM

There are some instrumentation isolators that may be good enough for audio, using a pwm system across capacitors.

Linear modulation of an IR diode driving a PIN diode works fairly well except at very low frequencies where I have seen strange non linearity and memory effects.

A transformer may be your best solution.

peranders · 13th March 2006, 07:07 AM

Seriously, I think it better to solve the casue of the ground loop problem. Have you built the gear or is it bought?

ostie01 · 13th March 2006, 07:54 AM

Hi, thanks for these great reply.Not built anything yet.It's for my 4way active crossover project.When I hook it up to a power amplifier, I got some hum in the speaker.Tried some tricks like disconnect ground from one end of interconnect but this is the worse I can do, more hum.tried some other interconnect with same result.

Just take a look at this link, this is my crossover project.Every cables is sheilded, separate transformer, each board has it's own filtering caps and voltage regulator. All capacitors are polystyrene or polypropylene for the bass output. all ICs are NE5532.Each ICs has a 22 Ohm resistor and a 22uF capacitor at the neg and positive input. Just let me know what you think. Thanks

http://img98.imageshack.us/img98/187...ssover17pl.jpg

http://img117.imageshack.us/img117/8...ssover20de.jpg

http://img95.imageshack.us/img95/565...arleur18eh.jpg

The last pic is a picture of my 4way speaker that I've built.

All my power amp are Rotel exept for the 15 inches drivers this are power by an Harman Kardon citation 7.1 with 450 watts/channel.

My crossover is built in a Rotel power amplifier case that has been modified, reduce in height to match the height of my Rotel line conditionner.Still have to finish the front(sanding and painting to match other Rotel components.

richie00boy · 13th March 2006, 08:02 AM

I suspect that your problem lies in an issue with your grounds within your crossover. When you have separate regs for different boards it can become tricky to keep everything starred properly.

ostie01 · 13th March 2006, 08:08 AM

HI, I know what you mean but the 2 boards have the same ground path.Each boards is grounded to the case.

ostie01 · 13th March 2006, 08:15 AM

Here is my design for the 4way crossover, should sound great if everything is O.K.

http://img92.imageshack.us/img92/103...sover114ai.jpg

richie00boy · 13th March 2006, 08:42 AM

If things are grounded to your case, have you used isolated input and output sockets? Also when you say grounded to the case, do you mean a star ground at ONE point on the case for ALL boards?

13th March 2006, 05:34 AM	#1
ostie01 diyAudio Member Join Date: Mar 2005 Location: quebec	optocoupler to eliminate ground loop Hi, would like to know if it's possible to eliminate ground loop problem with optocoupler or can it be used in amplifier input.Are they stable enough. Can I use this device to transfert analog signal like in audio circuit. Thanks everybody for your time. .

13th March 2006, 06:49 AM	#3
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	There are analog optocouplers but the quality isn't enough for audio I'm afraid. Check for instance IL300 from Vishay. I have used it in a 4-20mA loop and for this purpose it's OK. http://www.vishay.com/optocouplers/list/product-83622/ __________________ /Per-Anders (my first name) or P-A as my friends call me

13th March 2006, 07:07 AM	#5
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Seriously, I think it better to solve the casue of the ground loop problem. Have you built the gear or is it bought? __________________ /Per-Anders (my first name) or P-A as my friends call me

13th March 2006, 08:02 AM	#7
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	I suspect that your problem lies in an issue with your grounds within your crossover. When you have separate regs for different boards it can become tricky to keep everything starred properly. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

13th March 2006, 08:42 AM	#10
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	If things are grounded to your case, have you used isolated input and output sockets? Also when you say grounded to the case, do you mean a star ground at ONE point on the case for ALL boards? __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

13th March 2006, 06:09 AM	#2
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Look at datasheets of CP Clare....

13th March 2006, 06:52 AM	#4
davidsrsb diyAudio Member Join Date: Dec 2005 Location: Kuala Lumpur	There are some instrumentation isolators that may be good enough for audio, using a pwm system across capacitors. Linear modulation of an IR diode driving a PIN diode works fairly well except at very low frequencies where I have seen strange non linearity and memory effects. A transformer may be your best solution.

13th March 2006, 07:54 AM	#6
ostie01 diyAudio Member Join Date: Mar 2005 Location: quebec	Hi, thanks for these great reply.Not built anything yet.It's for my 4way active crossover project.When I hook it up to a power amplifier, I got some hum in the speaker.Tried some tricks like disconnect ground from one end of interconnect but this is the worse I can do, more hum.tried some other interconnect with same result. Just take a look at this link, this is my crossover project.Every cables is sheilded, separate transformer, each board has it's own filtering caps and voltage regulator. All capacitors are polystyrene or polypropylene for the bass output. all ICs are NE5532.Each ICs has a 22 Ohm resistor and a 22uF capacitor at the neg and positive input. Just let me know what you think. Thanks http://img98.imageshack.us/img98/187...ssover17pl.jpg http://img117.imageshack.us/img117/8...ssover20de.jpg http://img95.imageshack.us/img95/565...arleur18eh.jpg The last pic is a picture of my 4way speaker that I've built. All my power amp are Rotel exept for the 15 inches drivers this are power by an Harman Kardon citation 7.1 with 450 watts/channel. My crossover is built in a Rotel power amplifier case that has been modified, reduce in height to match the height of my Rotel line conditionner.Still have to finish the front(sanding and painting to match other Rotel components.

13th March 2006, 08:08 AM	#8
ostie01 diyAudio Member Join Date: Mar 2005 Location: quebec	HI, I know what you mean but the 2 boards have the same ground path.Each boards is grounded to the case.

13th March 2006, 08:15 AM	#9
ostie01 diyAudio Member Join Date: Mar 2005 Location: quebec	Here is my design for the 4way crossover, should sound great if everything is O.K. http://img92.imageshack.us/img92/103...sover114ai.jpg

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
ground loop	Jamh	Chip Amps	10	2nd November 2007 07:18 PM
Fix a ground loop!	sorenj07	Digital Source	2	1st October 2007 06:39 AM
hum,ground loop,earth loop problem with your answers please	frank2395	Pass Labs	2	17th May 2005 06:46 PM
does connecting mains ground with circuit ground create a ground loop?	jarthel	Everything Else	0	25th June 2003 12:55 PM
Ground loop hum	jag	Pass Labs	20	25th November 2002 05:32 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read