[fmzip]

Final mods completed

Wet Tantalum caps and foil pots & resistors.

 

[MartinWT]

How are you finding it? I have just received my Vishay trimmers, still waiting for the red WIMAs and polystyrene bypass caps.

 

[fmzip]

How are you finding it? I have just received my Vishay trimmers, still waiting for the red WIMAs and polystyrene bypass caps.

Powering it up very soon...

 

[b0bb]

@fmzip do you know who makes the SU2's slave clocks, the brand does not show up on search or the normal distributors.
A inquiry to your suppliers would be most helpful

 

[fmzip]

@fmzip do you know makes the SU2's slave clocks, the brand does not show up on search or the normal distributors.
A inquiry to your suppliers would be most helpful

I’ll have a look on Silcon Expert, a software platform we subscribe to at the office tomorrow to see what I can find

 

[wersuss]

Final mods completed

Wet Tantalum caps and foil pots & resistors.

What does the trimmers add? Where to measure them?

 

[fmzip]

@b0bb Here's the details on the parts from my engineering dept. Please let me know your thoughts on if they should/could be replaced.

They are made by Taitien. Digikey carries them. They come in two different sizes. One is the OY series and one is the OX series.

The part numbers are OYEUDCJANF-45.158400 or OXEUDCJANF-45.158400 and OYEUDLJANF-49.152000 or OXEUDLJANF-49.152000,
depending on the size you need.

 

[fmzip]

What does the trimmers add? Where to measure them?

https://www.head-fi.org/threads/l-k...s-double-impact.840938/page-223#post-16209848
https://www.head-fi.org/threads/l-k...s-double-impact.840938/page-227#post-16222142
https://www.head-fi.org/threads/l-k...s-double-impact.840938/page-227#post-16221367

 

[b0bb]

@b0bb Here's the details on the parts from my engineering dept. Please let me know your thoughts on if they should/could be replaced.

They are made by Taitien. Digikey carries them. They come in two different sizes. One is the OY series and one is the OX series.

The part numbers are OYEUDCJANF-45.158400 or OXEUDCJANF-45.158400 and OYEUDLJANF-49.152000 or OXEUDLJANF-49.152000,
depending on the size you need.

Thanks.

Taitien has a partnumber decoder on their website, the partnumber of the XOs are VTEMACJ-xxx

This is consistent with the TEMACJ designation on the case.

7mm x 5mm footprint size, 6 connection pads, 3.3V, CMOS output
This is the VT-M part: https://www.taitien.com/wp-content/uploads/2016/01/XO-0052-VT-MCMOS-Type.pdf


Voltage controlled XO, the control voltage is derived from the difference in the reference frequency and the current output frequency of the slave
Reference is either from the onboard SU2 reference crystals or the 10MHz external reference.

Performance is average, close in phasenoise is about 5.6x (15dB) worse @100Hz compared to the CCHD957 for a 50Mhz operating frequency
(-85dBc/Hz vs -100 dBc/Hz)

 

[fmzip]

Powered on my unit first time after the final mods.

My greatest fear became a reality, DEAD, nothing, NADA. After a few hundred superlatives my wife came up stairs and that’s when I noticed, forgot to plug in one of the power connectors on the PCB

Sigh of relief, warming it up to adjust the pots

 

[ESL57]

Have you tried to use a low DSD rate, if not lock it down to DSD64 and see what happens, check the display shows DSD64.
It is worth checking this again to confirm what DSD rate this problem is heard.

Measure the voltage output of the LT1763's supplying the 9038, nominal voltage output is 1.2V, nominal input voltage is 5V
Do this at cold start where you are not hearing the noise, repeat the measurement when you hear the noise.

Clean up the soldering mess, there is flux residue everywhere, especially around the I/V input and XO.

No matter the rate of DSD, since DSD64 (the file that I attached was DSD64) are already present, you just have to choose the appropriate low-level recording file to hear the noises more easily.
How could I make a DSD file without audio or very low level of pure tone for testing? can it be done by software or just by a DSD recorder machine?
https://www.diyaudio.com/forums/pc-based/282151-dsd-recording-software-etc.html
I have measured the output voltages of these adjustable version LT regulators, it is in the lower voltage that this chip works: in pin 1: 1.22v and in the input, pin 8: 3.8v, unfortunately I only have an old 20Mhz oscilloscope operating in right now, but at 0.2us on the time base and maximum sensitivity, I see fixed high frequency noise on pin 1, can it be normal? , looking for a better bandwidth of 200 or 300Mhz to see clearly what happens. More components are on the way to change and test in the meantime. Also clean the flux that I put myself in my multiple changes and tests and as expected for my misfortune it is just as noisy as before. If this were finally the fault of the firmware I would shoot myself, although I still enjoy this game and hope to nail the problem.

 

[dna301]

Powered on my unit first time after the final mods.

My greatest fear became a reality, DEAD, nothing, NADA. After a few hundred superlatives my wife came up stairs and that’s when I noticed, forgot to plug in one of the power connectors on the PCB

Sigh of relief, warming it up to adjust the pots

@fmzip Please tell us your impressions! waiting eagerly. My parts arecoming..

 

[b0bb]

I have measured the output voltages of these adjustable version LT regulators, it is in the lower voltage that this chip works: in pin 1: 1.22v and in the input, pin 8: 3.8v, unfortunately I only have an old 20Mhz oscilloscope operating in right now, but at 0.2us on the time base and maximum sensitivity, I see fixed high frequency noise on pin 1, can it be normal? , looking for a better bandwidth of 200 or 300Mhz to see clearly what happens.

pin8 is the LT regulator voltage input, 3.8V too low expected value is 5V.
Make sure your scope probe is properly grounded, it must be attached to the ground pins of the chip, the noise could be caused by improper grounding.

The other tps7a47 regulator supplies 3.3V to the 9038, it will not function properly with a 3.8V input, your upstream regulator supplying the 5V might be broken.

Repeat the measurement when the DAC is cold to see if the input voltage drops after warming up.

 

[oldearwax]

How could I make a DSD file without audio or very low level of pure tone for testing? can it be done by software or just by a DSD recorder machine?

Attached is a no sound pcm file, use pcm to dsd converter, which is available online.

 

[ESL57]

Se adjunta un archivo pcm sin sonido, use el conversor de pcm a dvd, que está disponible en línea.