Simple Mono to "Stereo" adapter

[Jeff Leites]

I have a portable radio with a mono headphone jack, so of course when I plug in stereo earbuds, sound comes out of only one bud. I want to make a simple cable adapter so sound will come out of both buds (duh! I realize it will still be mono ). So we'll have a common ground for both buds, but is it better to wire them in series, doubling the impedance, or parallel, cutting the impedance in half?

 

[dknguyen]

I would go with parallel. With such a simple method I think that worrying about impedance is nitpicking.

 

[AnalogKid]

Try parallel first. It they are typical earbuds with individual impedances of 16 to 60 ohms, driving them in parallel should not be a problem. Putting them in series will reduce the max volume possible by 50%.

Also, wiring them in series will mean the two voice coils are out of phase; that is, when one diaphragm is moving outward, the other will be moving inward. This will do strange things to your perception of the sound.

ak

 

[audioguru]

Since the cable has only 3 wires then you cannot wire the ear buds in series and in phase. Have you tried it in series and out-of-phase? It sounds weird.

 

[gophert]

A quick way to do series -out of phase, is only connect tip and ring (leave sleeve disconnected). Only move one wire.

 

[audioguru]

One day I was driving home from work and a song on the stereo radio began playing and sounding weird. I knew what they were up to. I quickly drove home and turned on a mono radio and many of the vocals in the song were almost completely cancelled.
The song was recorded with the two channels out-of-phase.

 

[gophert]

One day I was driving home from work and a song on the stereo radio began playing and sounding weird. I knew what they were up to. I quickly drove home and turned on a mono radio and many of the vocals in the song were almost completely cancelled.
The song was recorded with the two channels out-of-phase.

An engineer with a trained ear - audio was your destiny. I hope your employer knew how lucky they were to have you.

 

[KeepItSimpleStupid]

If the max volume is too loud, you can split resistively.

 

[audioguru]

An engineer with a trained ear - audio was your destiny. I hope your employer knew how lucky they were to have you.

Thank you. My audio career was 45 years long and I had 4 employers. Two of them rewarded me.

A few years ago my trained ear surprised me when a hearing test revealed that I needed hearing aids to hear the high frequencies. My new hearing aids made me young again and have features that normal hearing cannot do like noise reduction, directionality, extra sensitivity, compression and muting.

 

[Nigel Goodwin]

I would go with parallel. With such a simple method I think that worrying about impedance is nitpicking.

Yes, it's not even a question that needs asking - simply wire them in parallel - worrying about impedance isn't 'nitpicking', it's totally irrelevant

 

[dr pepper]

You can or at least you were able to get an adaptor, 3.5mm mono plug to a 3.5mm stereo socket, with the L&R in parallel.