Power pack creates 'hummmm' in wireless headphones
I have a wireless headphone with the transmitter hooked up to my TV. The headphones are '' SENTRY model HO800 ''. The headphones take two AAA batteries. The transmitter takes one 9v battery. Alternate to the 9v battery is a 12 volt 200MA power pack.
... Here is the problem > when using the power pack I get a really nasty hummmmm along with the TV sound in the headphones. Is it because the manufacturer instructions said to use a 12v power pack, ( verses 9v battery ), when the instructions SHOULD have said to use a 9v power pack? Seems to me that a 9v battery should be replaced with a 9v power pack.
.... If I find a 9v 200MA power pack I will need to splice in a 12v plug end because that is what the transmitter is set up for. In either case, 9v or 12v, how important is the 200MA rating? Would 1.7amp be a bad idea? How about a filter?
... Here is the problem > when using the power pack I get a really nasty hummmmm along with the TV sound in the headphones. Is it because the manufacturer instructions said to use a 12v power pack, ( verses 9v battery ), when the instructions SHOULD have said to use a 9v power pack? Seems to me that a 9v battery should be replaced with a 9v power pack.
.... If I find a 9v 200MA power pack I will need to splice in a 12v plug end because that is what the transmitter is set up for. In either case, 9v or 12v, how important is the 200MA rating? Would 1.7amp be a bad idea? How about a filter?
Electronics - Others
Answers & Comments
I don't think the 12V power pack is the problem. Generally there would be a regulator on the plug pack input to the transmitter (as power packs are notoriously bad at voltage regulation).
My guess is it an 'earth leak' between the TV and the transmitter via the audio lead. Does the powerpack have a earth pin. If so, are you able to plug it into an non-earthed power outlet.
If this isn't possible try removing the ground connection from the audio lead.
It could also be a bad audio lead.
Is the TV mono and the transmitter stereo or visa versa? You may need a mono to stereo lead.
Hopefully something in here will help.
I stumbled onto you posting of the Sentry headphones. I have the same headphones and love them. I had the same question as you. The best set up is a 9volt, 300ma. The 200 ma us underpowered. The 9v, 300ma power pack should plug in with no problems. I found mine at a Goodwill type of thrift store. I have been using the set for 4 years now and just let the transmitter run constantly. I wish I had another set for upstairs.