@ WarriorAnt
congrets for your decision
About "ticking noise" from the USB option inside V100 / V181 / V200
@ K_19
This comes from the relais which is in charge to switch to the converted USB signal when there is a valid signal.
Why there is a ticking noise ?
As you might know the switching from any analog input to a valid USB signal has priority over an analog signal.
To not harm any signal more than necessary, the switching from analog to the converted USB signal is made by a relais.
To avoid buttons or switches on the front panel all this is done automatically.
For this reason there is a circuit implemented to check if there is any "content" in the USB data stream and not only idle data.
When a "content" is detected, a relais is driven to connect the converted data with the amp circuitry.
Every time when there is no "content" (skipping tracks, stop, pause, invalid data) the relais will fall back and will generate a ticking noise.
This may also be heard in one or both channel(s) due to some small DC offset.
The solution:
As this behavior from the circuitry was often regarded as "nervous" we changed the fallback time from approx 1 second to about 6 seconds.
Now it takes about 6 seconds without "content" until the relais will fall back and the "ticking" noise is nearly solved.
This mods had been done in early spring this year.
As we didn´t knew that there is "old" circuitry inside the american market, Robert from AphroditeCU29 was not informed !!
Everbody may feel free to ship his "old" USB circuit or the entire amp to our place or to Robert for modification.
Again some words about the quality of the digital inputs (USB and OPTO)
The
USB 16/48 is made with PCM2702 from TI.
The circuitry is part of a USB-DAC family and the best in terms of D/A quality.
Unfortunately is is discontinued ...
Sample rate may be 44.1 and 48 kHz
The technical data reads -95 dB THD+N and 105 dB dynamic range.
This means it is average CD quality - nothing more.
We recommend this option to listen to MP3 music.
The
USB 24/96 is made with Tenor TE7022 USB receiver followed by TI´s PCM1793 DA converter.
This option is far more sophisticated !!
Sample rate may be 44.1, 48 and 96 kHz /
NO 88.2 kHz !!!
The technical data reads -100 dB THD+N and 110 dB dynamic range.
This means it is far more than average CD quality and would be good even for a stand-alone DA converter.
We recommend this option to listen to best MP3 music and "lossless" audio files.
The
OPTO 24/96 was made because there are many computers or notebooks having and optical output.
As USB (specially above 48 kHz) is sometimes difficult concerning the right drivers or the right software,
the optical connection is most times much easier to handle.
Also there wont be any hum issues !
Sample rate with this option may be between 28 ... 108 kHz and is not limited to some fixed values.
Here also PCM1793 is used as D/A with the above technical data.
Greetz for now
Fried