База знаний по hi-fi и high-end технике и комплектующим, отзывы и впечатления
Показаны различия между двумя версиями страницы.
Предыдущая версия справа и слева Предыдущая версия Следующая версия | Предыдущая версия Следующая версия Следующая версия справа и слева | ||
3sourse:1dacs:es9018 [2020/03/19 17:57] staudio |
3sourse:1dacs:es9018 [2020/03/20 14:27] staudio [Отзывы] |
||
---|---|---|---|
Строка 9: | Строка 9: | ||
https:// | https:// | ||
https:// | https:// | ||
+ | https:// | ||
==== Отзывы ==== | ==== Отзывы ==== | ||
+ | |||
+ | **Выход по току:** | ||
+ | |||
+ | The 47nf cap creates a corner 3db point of 23K without the preamp secondary impedance reflected to the primaries and 20K with it reflected. But that is not the reason why I have the cap. I discovered the effect of a cap across the legs on sigma delta DACs nearly 3 years ago by accident. I reported in the these posts | ||
+ | |||
+ | Practical Implementations of Alternative Post-DAC Filtering | ||
+ | |||
+ | |||
+ | |||
+ | That thread was started by a member who also noticed the same effect. He unfortunately got flamed for reporting it without adequate explanation. The effect is that is creates is a layering of instruments that makes listening to music - emotional. | ||
+ | |||
+ | The oldest reference I can find to this effect is here | ||
+ | |||
+ | http:// | ||
+ | |||
+ | Regarding the transformers - yes LL1544A is amorphous too. Nearly $85 in the US vs LL1674 which is $130 | ||
+ | |||
+ | The resistor value to be chosen depends on your taste. Put simply - the deeper you put the DAC into current mode (by lowering the resistor) - the THD improves. At 0 ohms - the THD is the best. | ||
+ | |||
+ | But in all honestly - I can*t hear THD in my system below -105db. | ||
+ | |||
+ | But I what I can hear is that the slam/ | ||
+ | |||
+ | The optimal value for the resistor is 4/5 times the output impedance of the DAC for my system. So 640 ohms for ES9028Q2M. | ||
+ | |||
+ | I thought so too initially that there was the HF explanation but there is some other mystery to be solved as well. Specifically - if you ground the caps, the effect is gone. In other words if you replace the 47nf across the pins with 94nf to the ground from each leg - the layering of instruments and the emotional connection is lost. | ||
+ | |||
+ | Also - if you vary the 3db corner - i.e. move it to say 30Khz - the effect is gone. It only seems to near the 20-22Khz region. I settled on 19.9 corner for my system. | ||
+ | https:// | ||
+ | ---- | ||
+ | **Выход по напряжению: | ||
+ | |||
Just a quick query because I can't seem to find anything but simple 2-page PDF datasheets for ESS DAC chips... | Just a quick query because I can't seem to find anything but simple 2-page PDF datasheets for ESS DAC chips... |