Between the op amp for the main line outputs and the L/MONO and R jacks, there’s only a coupling capacitor, a few resistors, and the muting transistor per channel. The headphone amp input is taken from the outputs of that op amp. Since you didn’t notice a problem on the PHONES output, muting transistor leakage is the only likely cause.

Since apparently the R DC measurement was low, it seems the muting transistor on that channel is OK. By having nothing plugged into the R while measuring the L/MONO, the only consequence would be that the measured DC would be somewhat lowered, due to additional loading by resistors at the R output.

Usually if the measured DC is fairly low, the muting transistor is OK. However, if a transistor is marginal, it’s possible for a high level signal to make it conduct, causing distortion. I don’t know for certain, but I suspect that the failure is usually due to connecting the outputs to an input which has phantom power turned on. Since one of the transistors is bad, and you don’t know the usage history of the XS, I’d suggest changing both main output muting transistors even though only one shows obvious leakage.

Alternatively, if the XS is connected to a mixer, you might want to verify that the channels are hard panned left and right. Also, sometimes a fault in a mixer can cause signal to bleed between channels.

But I’d start with TR11 and TR12.  :-)

Since I think it is good behavior to give feedback I am doing just that.. Thanks for the help so far,

I have finally changed the bad muting transistor TR11 yesterday.
Now I have no DC leakage and that is awesome. No distortion caused by leakage.....

However I still have minor issues with noticeable “zipper statics”.

The symptom seems to affect patches that uses LFO for Amplitude modulation like some Rhodes patches. If I set LFO Amp mod on a rhodes-like factory presets they too get the zipper statics. The zipper statics gets recorded if I record directly internally so it doesn’t seem to be induced by the JKAN-JA I/O board. The statics can best be heard if I play softly on low keys. If I change the LFO from triangle to square or saw it gets really noticeable but a square is rather obvious to cause problems.

Could this be a power supply thing that manifests as a minor issue??

Is it a fact that zipper noise can be heard on fully healthy Motifs on rare occasions or is my device broken ?

Built in diagnostics does not complain about anything. Have done factory reset and have the latest firmware/OS

helle - 07 October 2015 01:48 PM

Since I think it is good behavior to give feedback I am doing just that.. Thanks for the help so far,

I have finally changed the bad muting transistor TR11 yesterday.
Now I have no DC leakage and that is awesome. No distortion caused by leakage.....

You’re welcome - I appreciate the feedback, and I’m glad you were able to resolve the muting transistor problem.

 

helle -

However I still have minor issues with noticeable “zipper statics”.

The symptom seems to affect patches that uses LFO for Amplitude modulation like some Rhodes patches. If I set LFO Amp mod on a rhodes-like factory presets they too get the zipper statics. The zipper statics gets recorded if I record directly internally so it doesn’t seem to be induced by the JKAN-JA I/O board. The statics can best be heard if I play softly on low keys. If I change the LFO from triangle to square or saw it gets really noticeable but a square is rather obvious to cause problems.

Could this be a power supply thing that manifests as a minor issue??

Is it a fact that zipper noise can be heard on fully healthy Motifs on rare occasions or is my device broken ?

Built in diagnostics does not complain about anything. Have done factory reset and have the latest firmware/OS

Please see…
http://www.motifator.com/index.php/forum/viewthread/454443/
...and let us know if this is what you’re referring to.

5pinDIN - 07 October 2015 09:42 PM

Please see…
http://www.motifator.com/index.php/forum/viewthread/454443/
...and let us know if this is what you’re referring to.

Thanks for the quick reply.

Have not read the whole thread but everything so far seems to indicate that we have the very same issue. I even have similar AKG headphones as the XF user. I was thinking that the XS is fine for gigs but the zipper artifacts make it impossible for serious studio recordings, at least when using sounds that have this LFO stpping.

I will read everything and move myself to the other thread. Thanks

//Anders

helle - 08 October 2015 05:34 AM

5pinDIN - 07 October 2015 09:42 PM

Please see…
http://www.motifator.com/index.php/forum/viewthread/454443/
...and let us know if this is what you’re referring to.

After reading the whole thread and listening to the audio clips, I can say that my problem is not the very same and on a more anoying level. I probably have the aliasing too but my static noice is more like silent statics like from a record player (turntable).

My turntable statics is directly connected to the usage of LFO Amp settings. Not related to output level, or samples. I will post a demo later and a recipie to change Vintage ‘74 to make this statics.

If this is by design, I can go back to consumer mode and try to ignore or change the patches a bit but I am afraid that this is only my XS.

I will post a link from the other thread as well since my issue may be related in some way.

//Anders

Here is a short demo of the static artefacts that I experience when LFO amp is affecting one or more parts. The problem seems to be related to the “Fade in time” setting. If I have no fade in time, no issue. If the fade in time is set, the ramp up seems to create calculation errors that in my case sounds like a dirty record. The issue is noticeable when listening through headphones. Have used AKG 240 Studio for my test.

I used the factory preset

PRE1: 025 (B09) Soft Case

Edit -> Element 1

Elemetnt LFO

And set the following settings.

Wave: Triangle
Key On Reset: ON
Delay: 9
Fade in Time: 26
Speed 38
P Mod: 0
F Mod: 0
A Mod: 50

-------
Similar settings can be found in some 3:rd party banks too.

XS_LFO_static_ticks.mp3  (File Size: 780KB - Downloads: 249)

Another example from a 3rd party patch

Listen with good headphones and crank up the volume a bit. Most noticeable at the end of the clip

The frequency of the static ticks is directly related to the “Fade in Time”
Shorter fade in time quick burst of ticks, Long fade in gives the opposite,

This really seems to be a mathematical problem unless something is wrong with my unit. If I set fade in time to zero, the problem goes away and I would say it coulb be used in a studio recording.

I would really like to know if this is by design.. 

Off topic.. “Attach a file - Max Size: 20000KB” seems to be wrong..
I can not upload files larger than 2MB which is 2000KB

//Anders

XS_LFO_static_ticks3rdP.mp3  (File Size: 474KB - Downloads: 276)

Possible confirmation

Since I happen to have a Rack XS too, I tested changing the same factory presets according to my recipe and the same static stair stepping occurred.

To be sure, I did the test with other headphones, another keyboard connected to the Rack device, also performed the test on another floor..

The only things in common was my haircut, the power grid and that it was done on the same geographical location.

So I guess I’m pretty stuck with this zipper static.

My only curiosity is to know if this annoyance persist in the XF series too. I guess it does....

//Anders

The problem IS present when using the headphone jack - Motif xs7

And it’s a wobble sound in the sound banks.

5pinDIN - 09 April 2015 09:39 PM

helle - 09 April 2015 08:58 PM

[...]The problem is not present when using the headphone jack[...]

Since the PHONES output signal is the same one that goes to the L/MONO and R line outputs (other than a stage of amplification), you can forget about A/D converter and similar issues.

A likely cause is leaky output muting transistors. I’ve posted about the problem several times. All you need is a DC voltmeter connected to the line outputs for verification. Do a search - if you can’t find some threads discussing it, let us know and I’ll find them.