I've accepted that a 3.5mm jack cable from my phone to the 2B is never going to be an option.
So I've tried 2 options:
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Option 1:
I know that headphones work perfect (that have a 4pin 3.5mm jack plug)
So i bought a 4pin 3.5mm to 3pin 3.5mm female adaptor cable. (Attached image)
A normal pair of headphones (with 3.5mm 3pin plug) work perfect when plugged into this adapter.
When I plug the 3.5mm 3pin stereo cable into the 2B input and into the adapter, my phone swaps from headset to loud speaker as it doesnt think a device is connected.
Unplugging the 3.5mm jack from the 2B port and plugging it back in to the 2B males my phone swap back to headset and I get a stereo input on the 2B display... Hooray!!! But my success was short lived...
If there is a pause in the audio or I pause the sound file and press play a few seconds later... my phone then defaults to the loud speaker as it no longer detects a headset...
I'm convinced the port on my phone is slightly dodgy but crucially my phone is searching for a 'load' (or resistance) from the headphones...
A load that the 2B doesn't present to my phone.
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Option 2:
I purchased a cheap bluetooth receiver that outputs to a 3.5mm jack.
The plan is to connect the 3.5mm to 3.5mm stereo cable to the Bluetooth receiver and the other end to my 2B.
Yes... it works... but the volume output is so low, on full 'bluetooth' volume that the audio input display on tbe 2B barely reaches half way.
By messing with the EQ I can increase this to about 75% but with the eq maxed out... im expecting the signals to be "clipped" distorted and any subtle nuances in frequencies will be lost or over emphasised.
I've not even attempted to connect electrodes using this method as I believe the clipped /distorted signals could be unnecessary sharp/painful or have erratic/unexpected sensations.
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I dont believe the port on my 2b is faulty as it works perfectly fine from my laptop using the very same 3.5mm to 3.5mm audio cable.
So back to the drawing board... im admitting defeat and will have to buy a dedicated mp3 player just for stimmimg.
