GUSTARD DAC-X10 DAC ES901 (Support DSD)

[bogino]

I attempted to translate the linked post, but I don't have enough knowledge to understand that text. Hopefully I helped a bit.

Рекомендую также выкинуть тантал на выходе AD797 формирующей питание 3.3V аналоговой части ES9018 и заменить на хороший электролит, жетательно BG. Не переусердствуйте с номиналом, всему есть разумные пределы.

Сильно влияет на звучание, по уровню влияния сопоставимо с заменой керамики в частотозадающей цепи OPA1632. По хорошему здесь на замену AD797 нужен очень хороший малошумящий стаб.

I suggest also to exchange tantal on AD797 output, forming the 3.3V power supply of analog part, with a good electrolyt, ??? BG. Don't overdo with nominal, all has reasonable range. It has strong impact to sound, comparable with exchange of ceramic in frequency regulation OPA1632. For good result with AD797 exchange very good low noise stabiliser is required.

 

[androa76]

Today tried some different caps afer ad797
I changed 0,1uf MLCC before AD797 with pps 100n and after AD797 with 1uf pps. I took tantal out. Sound become very clean but a little to technically sounded. Replaced it with 3,3uf MKT wima ...sound was maybe too relax...at the end i deceided for 1uF pps + 1uf MKT wima.
100uf silmic2....to simple without emotions and atmosphere. Poor microdynamic.
I think that too big capacitive load is not a good solution after AD797.
Tomorrow i will tested it with heavy modded minimax dac.

 

[Patrik E]

This is a really interesting thread, i have a Gustard x10.
I have changed almost all metalcan capacitors for Silmic11 and that is a really nice mod.

 

[androa76]

Hay Patrick.
But before and after AD797 is no metallcan capacitor?
Can you post up pictures of your mods?
Can you describe what was difference in sound?
Did anybody replaced tl072 dc servo.
I change it for opa1642. I don*t know what to say. I must leave it for a day to burn in.
First impresion....too clean, some sibilance in female voices, instruments are to metallsounded. Bas is quicker but maybe less deep. Dc offset is 0.2mv vs 0.8mv Tl072 and a liiitle less noise at output.I will report in a few days. Next candidates will be opa2132 and 2134.
Can anybody tell me what is purpose in of adding 100ohm in series with 100pF in opa1632 feedback. I know that AD797 uses that combination. But why opa1632?
It is totaly different opamp. ANEIDO dac also use that combination on opa1632 feedback.
Why is in GUSTARD Vcom voltage only 1,25V. I will understand that it should be half of input voltage (3,3v) so that offset is near 0mv. Dc offset after fist stage is approx 0.45v. Does sending voltage on Vcom pin increase distorsion at output?

Let*s go on

 

[Patrik E]

Sorry but i have no Pictures.

 

[Patrik E]

androa you got pm.

 

[androa76]

Any new mods?
Forgot to say.
When start to tweak you should set filter in right position.
That is how it looks like at 20khz output.
When I have more time i will go on with mods.
Nice day.

 

[namcir]

So what can you say about the sound? About the quality? Pcb layout and parts selection? I am being tempted to buy but i want some more opinions...im comparing it to the matrix mini-i pro with es9016

 

[Patrik E]

I Think it is a really good buy for the Money, i have a friend that has a TP Buffalo and he Thinks that this sounds better than a standard Buffalo.
His Buffalo is the most extremmodded dac i have ever seen.
Gustard X10 is not perfekt but a good start.

 

[bogino]

I take a look inside the dac. Xmos is feeded from internall 5v ams3117 preregulator followed adp151 regulators. Only USB3118 transceiver is powered from externall usb 5v. It can be redesigned that is powered from dac but some mods must be done...left one diode out and connect one resistor.

Could you please give more detail, how it can be done and what for resistor do you recommend?