Moving from 9038Q2M to a 9028Pro board

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Hi babolcs,
Yes, a lot of work. Did you get the assembled board or the kit version?

Hi Mark i receivdthe assembled board.

The original sound is not that nice compare to the modded q2m.

Ive just realised that we really dd a nice job with the q2m. So many detals compared to the base config to this pro board.

Changed the ne5532 to lme49720 quite soon. Better sound but still very far.
At least a nice challange.
 
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Same principles here as with ES9028Q2M. Better power supply voltage regulators, better clock and the voltage regulation for it, improved output stage, etc.

Also, seems likely any brand name capacitors on the board are bad copies with fake part numbers printed on them.

It should probably sound better with a decent USB board on it rather than using SPDIF. Good if ASIO drivers can be used, otherwise need to check all Windows settings for the sound device to make sure Windows is not distorting the sound, etc.
 
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Same principles here as with ES9028Q2M. Better power supply voltage regulators, better clock and the voltage regulation for it, improved output stage, etc.

Also, seems likely any brand name capacitors on the board are bad copies with fake part numbers printed on them.

It should probably sound better with a decent USB board on it rather than using SPDIF. Good if ASIO drivers can be used, otherwise need to check all Windows settings for the sound device to make sure Windows is not distorting the sound, etc.

:)

Yes i remember to one of your former post regardng spdf and coax :).
Just somehow i had some potential issue or wathever with hifibeerry and q2m and the sound was broken some case so I changd back to spdf temporary.
(Was lasy to investigate.)
Currently i wouldnt go for usb since i bought hifiberry pro. But definitely will go back to rca/ coax.

I already bought the 3042s for avcc.and a lot of caps for power (nichicon and silmic.)
I can also use my former salas v1.3 psu here.
The 5907 was god for small Ldo functions here i thnk i will use the them too.
Just not sure how to realise the IV stage.
 
Same principles here as with ES9028Q2M. Better power supply voltage regulators, better clock and the voltage regulation for it, improved output stage, etc.

Also, seems likely any brand name capacitors on the board are bad copies with fake part numbers printed on them.

It should probably sound better with a decent USB board on it rather than using SPDIF. Good if ASIO drivers can be used, otherwise need to check all Windows settings for the sound device to make sure Windows is not distorting the sound, etc.


My questin i s - can be the pro chip fake too?
 
I've apply few mods of this thread on my ES9038Pro board ( Thank You ;) )

- Removed 47uF Fake Silmic II caps, and replaced with Wima MKS 10uF
- Remplaced the two LT1963 3.3 regulators with Dual LT3042 board (33K resistor for 3.3V & 22uF Tantalum cap for CSet)
- Aluminium & copper shield beetween transformers & DAC Board
- IEC filter and safty earth connection

Huge improvement in term of resolution and spacialisation

DAC5.jpg
 
Well this is probably the story of so many projects that begin working fairly well and never gets finalized and put into a chassis. It has taken two years to literally put the lid on this one but it is now done......with one more step.
Here is the list of things performed on this modification of the Chinese Ebay DAC.

OP Amps in IV section...changed to OPA1612 and OPA1611
Same op amps have been decoupled with 0.1uF caps
in IV stages, the LM317/337 three terminal regulators have been removed and the regulator replaced by a Jung Super Regulators using LM329 and LME49710. This regulator should be connected with a remote sense. This is actually an important point and should not be skipped especially since it costs 4 lengths of wires. It took two years to discover this.

Clocks changed to CRYSTEK ones. Said clock is powered by its own low noise LT3042 LDO. Remove the ferrite inductor on the main board and wire it back in and power the clock directly via one of the empty holes exposed. No cutting of traces is required.

On the circuit board, two LT1963 LDOs are fed by one rectified DC stages. One is for AVCC. The other one is for the clock shared with DVCC. Since the Clock has been separated DVCC has its own LDO now. Disconnect the other LT1963 that normally feeds AVCC on the DAC. I used come chipquik to make this process easier. I just lifted the pins and bent them back up. The exposed pads are now used to gain access to AVCC power line. I changed the power the first cap on the line with an OSCON 470 uF cap. I also changed the caps on this line to 10uF tantalums. The closest electrolytic ones to the ESS chip.
The power to the AVCC circuit is a SIGNIFICANT contributor the sound of the DAC. I tried high current LT3042s, large caps, Sulzer circuit with 317 preregulator, Jung style circuit using FET pass transistor off ebay, and finally using a JUNG SUPER REGULATOR.
Here was the order of preference of sound.

Stock LT1963 with large output cap.
High Current LT3042
Stock LT1963
Sulzer with 317 preregulator and an AD817
JUNG style FET regulator
JUNG superregulator using his GLED431 as a reference and an AD8031 op amp using REMOTE SENSE again. The remote sense allows the off circuit board to behave as if it literally was built right onto the circuit board. I had to manually trim the resistors to arrive at 3.5V DC for the output. Drift was a non issue here when the components are tied together with heat shrink. ( I did not use the exact components for the GLED circuit but hacked one together with a MPS 8x99 transistor and an LED I had lying around. The use of the real components will eventually filter in when I get my order in at Mouser for other components) . For the OP AMP I used an AD8031 that was suggested by Jan Didden. When I stumbled upon the GLED431 I also found another op amp that might be better the LT6200 of which there are three speeds...very fast op amps and very low noise that can operate at 3.3 Volts!

The main DAC board can be restored to stock form at any time by resoldering the items taken off or the leads that are bent like the LT1963. No invasive mods are performed.

The external power supply. This box supplies 15-15 AC, 6.3VAC, 6.3V AC, 12 VDC, 12 VDC, 5VDC all with their own transformer windings. All DC voltages from this box are OP amp driven FET regulators using 5534s are op amps. The 5VDC feeds a Y cable that connects to the USB cable to get a low noise 5VDC to the XMOS board rather than taking it from the PC.

So how does this sound? Well this project dragged on for a while and it came to a point with time restrictions and the fabulous reviews the TOPPING D90 was getting, I ordered one. Even after a week of break in, the TOPPING never sounded correct to my ears. After two weeks, it still sounds not correct. Where? there is something missing in the midrange energy. The D90 is going to leave the door now. Key lesson, remote sense is critical to getting Jung Super Regs to deliver what they are capable of.

Also anyone thinking of proceeding as a madman like myself should understand that a the total cost of this project possibly exceeds what a TOPPING D90 or similar DAC costs. Along the way I destroyed another DAC, destroyed an LTC6655 etc. However in the end I have something custom and I know it clear sounds superior to the D90. I am set for a while DAC wise now.
 

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Sorry, the top one is the least preferred. The last ones the most preferred. The last one being a HUGE change. As commented, the last one was hacked together with what I had in the parts bin.

For example the AD8031 is OVER ten time noisier than the LT6200. The bandwidth of the LT6200 is also multiple times more than the AD8031.
https://www.analog.com/media/en/technical-documentation/data-sheets/AD8031_8032.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/62001ff.pdf

Now look at the options on the LT6200 bandwidth! I'm worried about stability. I will build another AVCC supply but this time I will directly solder the package so it is better shielded by a ground plane. The Super Regs are super easy to fabricate and require no real exotic parts. I conversed with Jung himself and got a scolding about not using the EXACT parts recommended. I will do so in the next iteration. When the parts come in.

Difference in the D90 and all other PS supplies, the last octave change is profound with the remote sense. Not really where I expected to hear it. If you thought the soundstage of the D90 was wide. Well even with my compromised single AVCC, there is no comarison with the openness, depth and width. Guitars are so real, drums literally kick your chest now, as you would want.
 
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