Electronic Door Chimes

Thread Starter

GFord

Joined Mar 13, 2006
1
I have four Heath/Zenith electronic door chimes (the kind that can be set to eighty or so different songs) that I grouped into a common output speaker bus and amplified to be heard in seven remote speakers. Note the attachment I included with this message. The problem is that while it works for a short while one or more of the chimes will stop working and must be replaced. All I can figure is that the back feed of the output from one chime is damaging the other chimes. Is this a likely cause? If so then how can I prevent it?
Also, even if only one chime is hooked up to the amplifier I get a constant background hum on the remote speakers if the volume is turned up enough to actually be of use. Is there a way to filter out this background noise?
 

mozikluv

Joined Jan 22, 2004
1,437
hi,

buying a simple mixer will do but if you want to build it, then 2 pcs. of quad op amp to act as your buffer stage and a dual op-amp to act as your pre-amp.

you did not mention the capacitance value of your power supply filter. but a 2200uf electro cap will usually cure that humming. if it does not cure it, then something else is wrong.

moz
 

windoze killa

Joined Feb 23, 2006
605
Originally posted by mozikluv@Mar 13 2006, 11:37 PM
hi,

buying a simple mixer will do but if you want to build it, then 2 pcs. of quad op amp to act as your buffer stage and a dual op-amp to act as your pre-amp.

you did not mention the capacitance value of your power supply filter. but a 2200uf electro cap will usually cure that humming. if it does not cure it, then something else is wrong.

moz
[post=14935]Quoted post[/post]​
Could also do this using passive resistive mixing. Don't ask me the values as it has been a very long time since I had to work that out.

It has also been an even longer time since I have heard of Heath/Zenith. Must be 20 years.
 
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