GGGeoff

I agree it is a great DP with a superbly playable action. As you say you miss it, I take it you've used Bluetooth Audio + MIDI on a keyboard before? If so, how was the latency or delays? I would have appreciated USB audio support on the GP-510 (which I presume would enable WU-BT10 support as well). USB Audio would have greatly simplified my iPad interface project for PianoMarvel and Garage Band use. Instead, I have a collection of cables, adapters, a USB isolator, and a USB-C Hub for the iPad Pro. One more USB-C cable to clean that up is on order, and then I'll design and 3D print something contain that craziness out of sight behind the piano. Every digital piano has its quirks, though. What would be neat is, if in the interest of sustainability and product longevity, that if CASIO upgrades the electronics in the GP-510, say by offering USB Audio, Bluetooth, or even new samples, that we could upgrade just the logic board. I know, I'm dreaming... but hey.

Just an update on this. The amplifier sound distortion problem hasn't happened again, even when switching several times between the built-in speakers and headphones. I have, however, found a solution for the USB noise when connecting both USB and Audio Line In to the same device. The item that finally solved it is a USB Isolator. There are many kinds available, but I chose to go with the bare board from Adafruit, as I've had good luck with their products and appreciated their video explanation. The board must be switched to High-Speed for the CASIO to talk to my iPad. Basically it's an opto-isolator for the USB data lines, and power pass-through via a tiny on-board transformer, up to 100mA. That tiny board is plugged in using a small USB-A to USB-B adapter rather than a cable, thus keeping it tucked away under the piano out of harm's way. Between my iPad and my USB-C hub, I have a quality 4' USB-A to micro-USB right-angle plug into the isolator board. Adafruit USB Isolator Alternatively, I tried a line-level audio isolator, which also eliminated the USB whine, but then picked up some different environmental EMI noise itself from room lighting (though nowhere near as obnoxious as the USB whine was). The USB isolator ended up the winner since it doesn't introduce anything into the audio feed and accomplishes the goal of isolating the grounds of the two signal paths. I suppose I should put together a separate thread detailing my setup. Once I receive the final USB-C cable that will clean up the connection path from my USB-C hub to my iPad Pro, I'll take some photos. I may yet design and 3D-print an enclosure for both the USB isolator and the USB-C hub.

Interesting thought. Left minus Right would be all the out-of-phase stuff like hearing only reverberations, plus it would be mono. The first time this happened it was while trying out different headphones, and it affected the main speakers as well once I unplugged the headphones. The second time it happened was also while wearing headphones (Philips SHP-9600 wired open backs). Could be coincidence, or not. That it survives a Factory Reset and fixes itself by morning tells me it may be physical - like heat related. Could indeed be a dodgy connector. Oh, and the most affected sound was the Electric Bass... which if I remember right is about as close to a simple mono triangle tone as you can get. The Harpsichord sound was also strongly affected. Either one you couldn't hear the direct sound, but only the hall reverberation. Recordings were fine. The other unfortunate symptom is a pulsing digital whining if I connect both the USB Host and Audio Line Input to the same device (like an iPad or USB-C Hub). In fact, just connecting the shields of those two inputs together on my GP-510 results in the sounds. It's like the noises you used to get if you held an early LED calculator near an AM radio (yes, I just dated myself). If that noise is typical of these pianos, I figure I'll have to add up an isolator transformer on the line input from my iPad. Likely unrelated to the problem I started the thread, but curious if it's typical for this brand.

Hi Brad, Thanks for the reply. I'll be contacting my dealer today. As expected, the piano was completely back to normal in the morning, as if nothing at all had happened. Curiously, the WAV files that I recorded onto a USB thumb drive in the piano, when played back on my computer, sound perfectly normal. I don't know the architecture of the CASIO sound engine and amplifier chain, so I can only make educated guesses based on careful listening. Next time this happens, I'll record it with my iPhone.

Well it was a brief honeymoon. My nearly new GP-510 has gone off the deep end. The sound engine or effects processor has somehow corrupted its internal parameters. This is the second time it has happened. The previous time, I gave up and went to bed. The piano was back to normal by morning as if nothing had happened. The problem starts with the grand piano sounds: loss of stereo separation, loss of depth/volume, and certain notes (F#3, G3, G#3, and a cluster in the bass as well) sound quiet and thin. If you've ever heard an acoustic piano with two of three strings muted on a note during tuning, it's not unlike that. Selecting different tones, such as Harpsichord, or Electric Bass, provide stranger sounds... like you are standing at the very back of an enormous hall and hearing only reverberated sound. I managed to record some of the weird sounds onto a USB stick. When played back, they either sound just as weird, or different, but still not right. Playing a Concert Play piece, such as Raindrop, results in the provided piano track sounding incredibly distant, while the orchestra sounds almost normal, but not quite right. I have tried: Factory Reset in the menu, which does reset all settings, but is not a cure for this behavior. Adjusting hall reverb and position, as well as toggling through various scenes. Adjusting EQ, etc. Power off and unplug the DC Power supply, let the piano sit for a few minutes. Nothing has helped, other than last time of leaving it overnight, unplugged. Anyone experience this and know of a fix, like a true hard reset? Is this a usual bug? I'm thinking a call to my dealer is in order.

So we have a winner... Philips SHP9600. The Casio GP-510 can drive these headphones sufficiently loud - nearly as loud as the piano's built-in sound system. They are spec'd at 32 Ohms vs. the Sennheiser 560S's 120 Ohms. Bass extension seems to be a decent match to the GP-510 as well. The stereo imaging is remarkable. Like @Eli26 experienced, my first reaction was "oops - is the piano still playing on internal speakers??" My partner had the same reaction when he tried them on. We both remarked on how much more comfortable they are than the 560S's. Being open back they do leak some sound, but not enough to bother anyone in another room, let alone me playing late with the windows open. They also let in roughly 80% of the room sound, so I still hear the keyboard noises, passing cars, etc. These would not be a good headphone choice for someone needing to block or cancel outside noise. Thanks for the recommendation!

On my GP-510 the Berlin sounds a bit shrill / hard attack in the treble starting about F#5 when playing through the built-in speakers with the lid open and all defaults. I think it's the nature of the piano they sampled (likely perfectly voiced) combining with the well hidden tweeters aimed right at my ears. Turning the Brilliance down to -1 or -2 mitigates it, as does closing the lid. I'm particularly sensitive to certain kinds of tweeter setups, though. Someone with more knowledge of hi-fi once told me I was probably hearing crossover distortion and that not everyone is as sensitive to it. It has to do with you ear shape and all that.

Recently took delivery of a GP-510. Absolutely love it! Time to upgrade headphones for quiet/private practice. So my headphone journey thus far: Good old Bose QC20i's that I've traveled with for years. They work OK so long as I leave them powered off. When I power them on, they sound a LOT better, but then pick up a 60 Hz hum from the piano unless I ground myself the 1/4" headphone adapter. Turns out they also do that on my old Yamaha P120 digital piano now, so I suspect the cable connections / shielding are deteriorating. I might yet fix them, but I can tell they aren't ideal for the lovely sounds of the GP-510. It seems the hum is a common problem to the first-generation QC20i's and they are "fun" to fix... 16 hair-thin wires inside the brain-box. Sennheiser HD 560S open backs. Picked these up at Best Buy yesterday. Lovely sound! However, the CASIO can't drive them loud enough, so I end up playing the keyboard harder (and what's with the Keyboard Sensitivity setting being either inop or extremely subtle?). The Sennheiser's are rated 120 ohms impedance. My MacBook Pro can drive them plenty loud, and they sound great, but that doesn't help the piano. I'm not keen on adding a headphone amp to the piano. I try to keep the piano as much "sit down and play" as possible. AirPods Max. Very seriously considered after auditioning them in the store. Wow. Super build quality, very comfortable, and amazing sound. Unknown as to how latency and sound stage are when using the optional analog input cable, since all of the active EQ happens in the digital domain. Also unclear if they'd be loud enough. Yet another thing to keep charged up, and there's that little issue of longevity. I expect my headphones to last at least a decade. But Max's sure are nice. I suspect they'll either see a update in the coming months, or be quietly discontinued. They remind me of the original HomePod... very nice, but, hmm. Philips SCH-9600... after reading this thread, I figured they would be worth a try. Awaiting delivery of them today. If they check all the boxes, then I'll be a happy midnight pianist. Thanks everyone!