I turned on my mf8 last night, and then it all went bad.  It opens by factory default to “InnerWind” on the performance mode. When I struck a key expecting to hear the normal arpeggios, the sound was all distorted, the percussion levels significantly low.  I then tried out some voices.  The “Full Grand” on the presets sounded fine, but the “phase Wurli” had significant loss of volume output without changing any settings.  Yesterday morning all was fine.  And then this.
So I returned to factory default.  Everything was still screwed up.  Some peformances sound fine, others not.  So too with preset voices.  I do not believe there were any physical changes made during the day.  Im a bit frantic.

Let’s try to narrow the possibilities…

Disconnect everything from the XF except its power cord - that is, any audio cables, pedals, MIDI, USB, Ethernet, etc. Plug a pair of headphones into the PHONES jack. Is the problem evident with headphones?

The problem is only evident with headphones.  Did as suggested and disconnected pedals (I was only using headphones, no MIDI or other connections). Problem persisted. 
I did, however, finally connect to a keyboard amp to compare to sound in headphones.  The amped sound was fine/normal as expected, so the problem seems to be in the Motif’s headphone jack.  Don’t know what that could be in light that there were no physical changes from when it worked fine to when the problem appeared. 
I kinda need the headphone jack to work (I could use headphone jack in keyboard amp, but that is not convenient--though sometimes convenience has to give).  Is that going to be an expensive problem to solve?

That’s an unusual situation.

The PHONES output is the same signal as fed to the main L/MONO and R line outputs, although it does go through an additional stage of amplification to drive headphones. While it’s possible for a problem in that stage, it certainly isn’t common.

Are you hearing left-right separation in the headphones when playing a stereo source on the XF?

Have you checked operation of the headphones on other gear?

Is the keyboard amp stereo? If not, did you check both L and R line outputs of the XF?

Okay, sorry for long delays in responding; appreciate help greatly.

Headphones work fine on other gear.

When both outputs send (stereo) to Roland KC550, in performance mode seems “tinny”, low end seems to diminish when panned to center.  Also voice mode seems to be same (Grand Piano sounds loud, but missing low end; Phase Wurli signal seems excessively weak, lots of reverb). 

When panned to full left or right, low end seems to come back. 

When only one output goes to amp, sounds fine but obviously mono (all 4 parts seem normally balanced.  This is true for both outputs alone (L/mono; R).  Again, when both L and R go to amp together, there is a problem unless I pan to one side or the other.

Im not tech savvy, but this seems strange.

Your description of the way things sound when the KC-550 is fed both L and R signals “sounds” like the amp is causing phase cancellation. The KC-500 is a mono amp, and if the XF sounds OK when the amp is fed only the L/MONO signal (with nothing plugged into the XF’s R output jack), then that’s about as telling as can be determined. A better test would be stereo amplification, such as a pair of powered monitor speakers.

Getting back to the headphone issue, please answer my earlier question…
Do you hear stereo separation from headphones connected to the XF? If you’re not certain, turn off effects and pan a Voice fully left or right.

Im sorry.  There is stereo separation in the headphones alone, but the sound issue remains. 

When signal goes through powered monitor speakers, there is also stereo separation, and the sound issue does not seem to be a problem with the voices as it is in the headphones, or when both L and R are panned center and sent to amp.

So short answer, powered monitor speakers don’t have the problem that the phones and the amp do.  And that doesn’t seem to make much sense to me.

Ugh!  I meant that there is no real stereo separation in the headphones.  When panned L or R, voice comes through both ears, although there is a slight difference in tone in Grand Piano.  Phaze Wurli very week in volume and reverb very high.

There is stereo separation with powered monitors.  To be clear, when the L/Mono output goes to amp to the L/Mono input, sound is fine (but obviously mono).  When the R output goes by itself to amp (to R input), sound is fine (but same sound, and mono).  When both outputs go to amp, there is a problem when pan is center (seems one or two channels get muffled in performance), but not when panned to L or R. 

And so yes, powered speakers do not exhibit same problem.

frdgb - 28 June 2019 07:29 PM

Ugh!  I meant that there is no real stereo separation in the headphones.  When panned L or R, voice comes through both ears, although there is a slight difference in tone in Grand Piano.  Phaze Wurli very week in volume and reverb very high.

Your previous post had me wondering what was going on. The above description, however, seems to make sense.

Although I can’t be certain, based on your description I suspect a bad headphone jack ground. That sort of thing can happen if the headphone plug gets hit while it’s inserted in the PHONES jack, for example.

If the common ground connection for headphones is lost (due to either a failure of the jack or a bad solder joint), what you’ll hear at both ears (mono) is the difference between the signal from the two channels. That results in cancellation of anything that’s common to the two channels - it typically affects lower frequencies more (their volume is reduced). Effects are accentuated, especially those that induce phase shifting between the channels.

One thing you can try, while listening with headphones, is to gently apply some pressure on the plug in various directions and see if normal sound can be temporarily restored. If so, that would definitely point to a connection problem with the jack.

 

frdgb -

There is stereo separation with powered monitors.  To be clear, when the L/Mono output goes to amp to the L/Mono input, sound is fine (but obviously mono).  When the R output goes by itself to amp (to R input), sound is fine (but same sound, and mono).  When both outputs go to amp, there is a problem when pan is center (seems one or two channels get muffled in performance), but not when panned to L or R. 

And so yes, powered speakers do not exhibit same problem.

Since the problem isn’t present with powered speakers, it’s likely that the XF is otherwise OK. The L/MONO output, as long as nothing is plugged into the R output jack, is a mix of left plus right channels. While that can cause some loss of certain frequencies due to phase cancellation, if it sounds OK by itself that further suggests there’s nothing wrong with the XF other than a PHONES jack issue.

I can’t determine what might be going on with the KC-550 when its mixer is being used with both channels, but for now I’d chalk that up to some idiosyncrasy of the Roland amp.

Thank you very much, for both the diagnosis and your patience.  Now...if there is a bad jack ground, is it gonna be a hard thing to fix, as in who can fix something like that?

frdgb - 29 June 2019 11:57 AM

Thank you very much, for both the diagnosis and your patience.

You’re welcome.

 

frdgb -

Now...if there is a bad jack ground, is it gonna be a hard thing to fix, as in who can fix something like that?

It might be good to first verify the diagnosis. Do you have access to an ohmmeter (multimeter)? If so, a quick check can be made of the PHONES jack ground connection, without opening the XF. There should be close to zero ohms from the headphone plug’s sleeve to a nearby screw on the XF’s rear panel. (The plug would need to be the type that either has a metal shell or at least some part of the metal exposed when the plug is fully inserted. Any 1/4” phone plug that meets the requirement is sufficient, it doesn’t have to be from headphones.) If the resistance reading isn’t close to zero ohms, then the jack’s ground connection should be further checked by a qualified technician.

NOTE: The above should only be done by someone who is familiar with such testing. Power to the XF should be disconnected (unplugged) during the test.

By the way, if the headphones are the type that have a 1/8” (3.5mm) plug and use an adapter to 1/4”, check the adapter. Some of them don’t make reliable connections.

Update: electronic friend checked Phones jack.  The problem, however, seems to be with the phones plug itself.  It worked fine on my amp, on my stereo, and so forth, but seems to have not made a properly good connection on the Motif.  A new phones plug worked fine. Friend said it was odd, but the ground was good and the plug also failed in one of his amps, but not in other gear.  But all good now.  Thanks again for the help.

Thanks for the update. Apparently the sleeve of the headphones’ original plug wasn’t making a good common/ground connection to the XF’s PHONES jack. It’s certainly unusual for it to work adequately in several pieces of gear, but not others. Hopefully replacing the plug is a permanent resolution.