XV-5080 sound issues

Hello David,
Could you try disabling the effects to determine if it is one of them?

In particular,
I believe that it may be one or more of the following effects:
LoFi (Effects that intentionally degrades the sound
quality)
50: LOFI COMPRESS
51: LOFI NOISE
76: STEREO LOFI COMPRESS
77: STEREO LOFI NOISE

Cheers, Hanon

Hi Hanon,

Thanks for the quick response! I don't believe this is one of the effects - it actually drowns out a lot of the patches, being as loud as the patch itself.

Am I right in thinking that if I press the Effects on/off button and make sure all of the four effects sections say 'Off' then I am not applying any effects to the patch at all?

I have done a complete factory reset too, which does not help.

Thanks again,

David

Yep,
you're right, that turns them off.
I thought that I'd suggest the easy test first.
It may be an internal defect, and require repairs.
Cheers, Hanon

UPDATE: The problem seems to diminish significantly as the unit warms up - over two hours or so after power up.

Any clues?

David

drb27 wrote:

UPDATE: The problem seems to diminish significantly as the unit warms up - over two hours or so after power up.

Any clues?

David

Did you get a hang of it?

same things on the mine. there's some noise when playing phrases. but not as much as yours.
I've replaced the faulty encoder and I will make a recap on the power supply unit and see if it solve the problem.
+5V is measured @ 5.209V on the PSU output
if the crackling noise is on all outputs (even spdif) perhaps a master clock problem?

and the culprit seems to be....IC13...
when unit is warm and the sound is ok, if I use freezing bomb on iIC13 the crackling noise appears....until the chip warms again...

I will try to check all the master clock chain components and especially the TLC2932 PLL.

it's not a power supply voltage problem because I've modified the feedback loop to get 4.97V instead of 5.2V and the noise is here.

It seems to be fixed....C71(10uF 16v) or one in parallel capacitor (or the regulator) seems to be the origin of the trouble.
adding a cap in parallel while playing the sound remove the crackling noises. so it seems to be a supply decoupling/bypass capacitor problem!
now I have a 100uF capacitor in parallel of C71 for test and I'm waiting the unit to be cold but at this time I have no more crackling sound.

when I measure the voltage across the capacitor there is an ripple on it.
adding capacitor remove this ripple.
I must go further to see if it's a lack of decoupling or the 3.3V regulator the problem.
a video showing when that when I press the button to add a capacitor in parallel, the noise diappears
https://youtu.be/vwuwc0zHgW4

here are some pictures of the tests
where the scope is connected with short ground link (ripple noise method)


and here the results

420mV of ripple noise!
the frequency seems to be near 378KHz

and now with the cap connected with the same scale as before


the current is measured at 350mA max. (important for me to choose a new regulator)


done:
- PSU feedback modification to get 5V instead of 5.2V
- clock + PLL check

-> next steps:
- PSU recap - (tomorrow)
- try to replace the LDO regulator because the bypass caps seems to be ok -> faulty (noisy) regulator?
I'm searching for a good replacement part because the original is hard to find.
the output noise must be near 55µV and rejection ratio at least 64db with line regulation near 15mV and load regulation 25mV to be the closest possible to the original one.

Confirmed! it's a power supply problem.
I've replaced the voltage regulator and the problem is gone! \o/
and even before to recap the PSU and without the test bypass capacitor connected.
Ripple is now at 90mV instead of 400mV

a video before:
https://youtu.be/4nW7qyra8vM

and after replacing the regulator
https://youtu.be/BAUrQvggS78

solved! :)

I must make more tests because the capacitors even if they seems ok with multimeter, they looks bad under LCR meter with huge ESR.

so for someone having the same trouble the best to be sure is to replace:

-C79 -> the mine was measured at 1uF instead of 47uF! -> replaced
-C71 -> the mine was measured at 6uF -> replaced
-C75 -> the mine was measured at 5uF instead of 10uF -> replaced
- and at the end the LDO if replacing caps doesn't work


But my unit works well now with the new regulator :)

When the bypass capacitors are replaced the ripple is even lower with the new regulator.
I don't want to go back and test with the old original LDO but you can try in first intention to replace the three aluminium capacitors C79 + C71 + C75 to check if the problem is solved only by replacing these parts before to go further.

well well well....C249 is measured at 13uF instead of 47uF....I think the rack is running hot and the big problem is the capacitors....aluminium capacitors doesn't like heat....a complete recap could be a good idea I think.....

well. recap of SMD aluminium caps is done for the mainboard and I HIGHLY RECOMMEND to the XV-5080 owners to do the same (or ask to a service dpt to do it).
I have used Nichicon 105°C 2000HRS CD serie caps as replacement (5000HRS were not available with low esr and same size).

I think pictures are better than words


yes! nanofarads!


I've measured each old cap value and made a table


no comments! now I'm pretty sure the regulator was not the origin of the problem but the lack of bypass capacitance!

all works well but even with a psu recap there's lot of ripple at the psu output. the output voltage is badly regulated. It's not a PSU failure, it's from design.
you can't hear it but the PSU make a buz noise at the boot and I don't like it. the ripple when a light load is connected (boot of the XV is near 880mV peak to peak for the 5V output!)

it's a very bad designed PSU (no controller only a quasi resonnant flyback design with feedback) and I strongly encourage people to replace this bad PSU by a good one.

I've used a XP power ECM40UT33 medical grade for my XV. it's not so expensive 45€ and it's a good quality one with lot of protections and good line/load regulation. (I've compared several other models from RS, traco, artesyn etc)
some simple wiring is required and 3 holes to drill but it gives you peace of mind.

Voila :) the new PSU is installed (left) and the old one (right)

As a technical question regarding the ECM40UT33. I have yet to measure my own xv-5080, but from your text you mention 3,3V and I can't see the ECM40UT33 having that output but 5V 15V -15V.

Any thoughts?

Cheers

the 3.3V is generated onboard with a regulator but the power supply output is 5V ;)