Piano Tone Posted June 20, 2022 Share Posted June 20, 2022 I had someone on my YouTube post on the Casio PX-S1100 (which only has audio in via BlueTooth - they removed the 1/8" audio in port that the 1000 had) say that they've been using one of the headphone ports as an audio in. I thought they must have been mistaken so I tested that on my PX-S3000 and yes it does work as an audio in! I will be testing this on the other keyboards I own right away but wanted to ask if anyone has noticed this before, and is this normal??? Seems pretty bizarre to me . . . Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted June 21, 2022 Author Share Posted June 21, 2022 Seems to be an issue / “phenomenon” only on the PX-S privias. I tested this on my Casiotone CT-S1, and my Yamaha PSR-EW425 and the headphone ports behave normally on those 2 (no mysterious audio in functionality). Quote Link to comment Share on other sites More sharing options...
Jokeyman123 Posted June 21, 2022 Share Posted June 21, 2022 Stupid question but....does the headphone jack work....as a headphone jack? Its definitely not "normal". I can't imagine how this is even electronically possible, since the electronic input/output signals should be isolated from each other, the electronics values would be entirely different, as would the circuit components. An audio input should be either line level or microphone level, and the headphone out jack would be very different-needs a different signal level to match with headphones. Very peculiar, unless somehow the wiring is jumpering from one circuit to the other, erroneously? and I'm not too sure this is a "healthy" situation circuit-wise. "Impedances' can do strange things sometimes-since it is an AC signal, there can be current feeding back and forth through circuits that have "coils", and the headphone jacks inside have coils...at least on the PX's I've opened and repaired. Still very odd, and probably not good long term. I wonder are all the PX-3100's like this? 1 Quote Link to comment Share on other sites More sharing options...
IanB Posted June 22, 2022 Share Posted June 22, 2022 Going out on a limb a bit here but... Without looking at the circuit diagram, I'm guessing the headphone jack comes off the power amplifier somwhere via a resistance and thus a low impedance audio signal can perhaps backfeed into the power amp. Just guessing. 1 Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted July 19, 2022 Author Share Posted July 19, 2022 (edited) On 6/21/2022 at 9:21 AM, Jokeyman123 said: Stupid question but....does the headphone jack work....as a headphone jack? Its definitely not "normal". I can't imagine how this is even electronically possible, since the electronic input/output signals should be isolated from each other, the electronics values would be entirely different, as would the circuit components. An audio input should be either line level or microphone level, and the headphone out jack would be very different-needs a different signal level to match with headphones. Very peculiar, unless somehow the wiring is jumpering from one circuit to the other, erroneously? and I'm not too sure this is a "healthy" situation circuit-wise. "Impedances' can do strange things sometimes-since it is an AC signal, there can be current feeding back and forth through circuits that have "coils", and the headphone jacks inside have coils...at least on the PX's I've opened and repaired. Still very odd, and probably not good long term. I wonder are all the PX-3100's like this? Not at all a stupid question given the bizarre nature of this issue, and yes it does work as a headphone jack I don't know how this is happening either. I did test this on my other 2 boards (Yamaha PSR-EW425 and Casiotone CT-S1) and thankfully no, those don't have this issue they work normally. But yes it does make you wonder if this is a "healthy" situation for headphones. I'd have to guess they probably are all like this because I heard about this from someone on my YouTube channel; I had a post on the PX-S1100 saying I wish they hadn't removed the 1/8" audio in that the PX-S1000 had from the PX-S1100 - and the person commented that they use one of the headphone ports on their 1100 as an audio in (which is what got me to confirm it's like that on my 3000 as well) Edited July 19, 2022 by Piano Tone Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted July 19, 2022 Author Share Posted July 19, 2022 On 6/22/2022 at 5:44 AM, IanB said: Going out on a limb a bit here but... Without looking at the circuit diagram, I'm guessing the headphone jack comes off the power amplifier somwhere via a resistance and thus a low impedance audio signal can perhaps backfeed into the power amp. Just guessing. I have zero wiring / electrical knowledge (so I don't know exactly what you mean by backfeeding), but one thing to add is that the quality of the audio in signal that I get on this port is 100% as good as the actual audio in port on the back of the piano (if I didn't know which one I was using I wouldn't know the difference). Hey maybe I should plug some headphones into the audio in on the back and see what happens . . . . 1 Quote Link to comment Share on other sites More sharing options...
Jokeyman123 Posted July 20, 2022 Share Posted July 20, 2022 Eek, here is my last "guess" someone at the factory did not solder something properly-or there is a solder bridge somehow managing to do this trick. No way this should be working, and well, unless the wiring is completely wrong on the audio or input board. I know speaker outputs can be modified with a resistance network to work as a headphone output (all these new cheap Chinese amps have no headphone outputs i was dismayed to find-how cheap can you get...which is why I looked this up) but the opposite turning an output into an input...got me! Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted July 25, 2022 Author Share Posted July 25, 2022 On 7/19/2022 at 12:45 PM, Piano Tone said: I have zero wiring / electrical knowledge (so I don't know exactly what you mean by backfeeding), but one thing to add is that the quality of the audio in signal that I get on this port is 100% as good as the actual audio in port on the back of the piano (if I didn't know which one I was using I wouldn't know the difference). Hey maybe I should plug some headphones into the audio in on the back and see what happens . . . . Ok so out of morbid curiosity I plugged headphones into the 1/8" audio in on the back (part of me was expecting them to work ) but alas they did not so that port seems to work as expected. Quote Link to comment Share on other sites More sharing options...
Jokeyman123 Posted July 25, 2022 Share Posted July 25, 2022 (edited) There is one other possibility-Casio is not always accurate with documentation in their manuals for the sake of brevity perhaps, so this may actually be the way it is supposed to function, surprisingly since all of the PX-S3100 are the same. Several of my laptops-an older Dell Motion 1400 and 1700 for example-use the same jack for audio in and out-these switch the functions with internal software, and it works, I guess by detecting the 2 different "impedances" for an input and output device-not a small task for software but the Motion tablets were pretty advanced for their time, still are. Especially considering the input might be 2-input and the stereo output has to be 3-input. I also have a laptop or 2 that also works like this-and pops up a message describing the change of use, as do the Motions. I would like to hear from Casio JAPAN if they can clarify the issue. if it is a design function, would seem that there would be a description in the manual somewhere about this as it is definitely a useable feature! I did not see anything but maybe I missed it. Edited July 25, 2022 by Jokeyman123 1 Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted July 25, 2022 Author Share Posted July 25, 2022 4 hours ago, Jokeyman123 said: There is one other possibility-Casio is not always accurate with documentation in their manuals for the sake of brevity perhaps, so this may actually be the way it is supposed to function, surprisingly since all of the PX-S3100 are the same. Several of my laptops-an older Dell Motion 1400 and 1700 for example-use the same jack for audio in and out-these switch the functions with internal software, and it works, I guess by detecting the 2 different "impedances" for an input and output device-not a small task for software but the Motion tablets were pretty advanced for their time, still are. Especially considering the input might be 2-input and the stereo output has to be 3-input. I also have a laptop or 2 that also works like this-and pops up a message describing the change of use, as do the Motions. I would like to hear from Casio JAPAN if they can clarify the issue. if it is a design function, would seem that there would be a description in the manual somewhere about this as it is definitely a useable feature! I did not see anything but maybe I missed it. Given that there is a 1/8" audio in on the back I would be surprised if it was intentional, and the manual only refers to the ones on the front as headphones but who knows - if it was intentional, they should be including that in the specs of the new PX-S1100 because I've had multiple subscribers on my channel say they are either looking for used PX-S1000's or other products entirely because they removed the 1/8" audio in from the back of the 1100. Quote Link to comment Share on other sites More sharing options...
sthubbar Posted August 9, 2022 Share Posted August 9, 2022 Thank you for letting me know about this hidden feature. I am also able to input audio into one of the headphone jacks and have it play back through the other headphone jack. I was unable to get the sound to also come out of the built-in speakers. One issue I have found is that when the "input" is connected to my iPad 8 there is distortion of the piano sound, even without any audio coming from the iPad. There is no such distortion from my phone, or iPad mini 2. Quote Link to comment Share on other sites More sharing options...
Jokeyman123 Posted August 11, 2022 Share Posted August 11, 2022 ??? Input audio in one jack and out there other? This is even more bizarre, I don't think this is meant as a hidden feature. Something is wrong. None of my dual headphone jack Casios (or any other synth I own) does this. I would like to hear the official feedback on this one from Casio. Like turning on the water faucet and your refrigerator opens. Have to do the spaceship for this one. Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted August 11, 2022 Author Share Posted August 11, 2022 12 hours ago, Jokeyman123 said: ??? Input audio in one jack and out there other? This is even more bizarre, I don't think this is meant as a hidden feature. Something is wrong. None of my dual headphone jack Casios (or any other synth I own) does this. I would like to hear the official feedback on this one from Casio. Like turning on the water faucet and your refrigerator opens. Have to do the spaceship for this one. And you can use either one as an input and the other as output . . . We have travelled to the twilight zone. I posted it in Casio keyboards Facebook group as well, none of the Casio reps chimed in Quote Link to comment Share on other sites More sharing options...
Brad Saucier Posted August 11, 2022 Share Posted August 11, 2022 I have read this thread several times looking for the rest of the story. Maybe I missed something. On 6/20/2022 at 10:30 AM, Piano Tone said: I had someone on my YouTube.... say that they've been using one of the headphone ports as an audio in. ....I tested that on my PX-S3000 and yes it does work as an audio in! But no mention of where the sound is exiting. On 8/8/2022 at 11:28 PM, sthubbar said: I am also able to input audio into one of the headphone jacks and have it play back through the other headphone jack. I was unable to get the sound to also come out of the built-in speakers. This mentions the sound only exits the other headphone jack. Is anyone explicitly saying the sound is exiting the speakers in the keyboard? 1 Quote Link to comment Share on other sites More sharing options...
IanB Posted August 12, 2022 Share Posted August 12, 2022 Relating to Brad's comment, it sounds to me simply that the headphone jacks are in parallel, so what goes in one comes out the other. Same as using a Y splitter. 1 Quote Link to comment Share on other sites More sharing options...
Davespider Posted August 24, 2022 Share Posted August 24, 2022 IanB, I agree, and not correctly summing a line level and headphone level signal is bound to phase cancel and distort. My understanding is there are 2 headphone port and 1 aux in on the back.. 1 Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted August 25, 2022 Author Share Posted August 25, 2022 23 hours ago, Davespider said: IanB, I agree, and not correctly summing a line level and headphone level signal is bound to phase cancel and distort. My understanding is there are 2 headphone port and 1 aux in on the back.. On the 1000/3000 there is an aux in on the back. On the 1100, they removed that port in favor of bluetooth; but as someone on my channel noticed, they can use one of the headphone ports as an in anyways Quote Link to comment Share on other sites More sharing options...
Piano Tone Posted August 25, 2022 Author Share Posted August 25, 2022 (edited) On 8/11/2022 at 8:16 AM, Brad Saucier said: I have read this thread several times looking for the rest of the story. Maybe I missed something. But no mention of where the sound is exiting. This mentions the sound only exits the other headphone jack. Is anyone explicitly saying the sound is exiting the speakers in the keyboard? I don't have my 3000 anymore so I can't test this any further, but no the sound wouldn't have been exiting the speakers (since the headphone port is in use which disables the speakers); the sound would exit out of the other headphone port if headphones were plugged in. What I'm wishing I had tested when I still had it is to see if the audio in coming through the headphone port would be included in the L/R line outs and (or) recording to the USB flash drive. Edited August 25, 2022 by Piano Tone Quote Link to comment Share on other sites More sharing options...
Brad Saucier Posted August 25, 2022 Share Posted August 25, 2022 15 minutes ago, Piano Tone said: but no the sound wouldn't have been exiting the speakers (since the headphone port is in use which disables the speakers); The PX-S3000 and 3100 have a function to enable the speakers while something is connected to either headphone jack. In my previous post, I was leading to what IanB mentioned. The headphone jacks are likely simply in parallel, and nothing is actually being received by the keyboard. I wouldn't be surprised by this at all, and would not be surprised if no sound is heard from the line outputs or audio recorder. 1 Quote Link to comment Share on other sites More sharing options...
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