Ton skrev:Hur är det med transporter, har den digital volymkontroll eller inte? Känns annars som den optimala spelaren tillsammans med ett slutsteg.
Ja, men...
http://wiki.slimdevices.com/index.cgi?ConnectToPowerAmpEfter som den dämpas analogt ...
SlimDevices skrev:Transporter Built-in Attenuation
The Transporter provides built-in line level attenuation for the RCA unbalanced connectors. Balanced attenuation must be provided externally.
The internal attenuation is provided using an internal jumper setting inside the case. Four attenuation levels are provided: -30dB, -20 dB, -10 dB and 0 dB.
What line levels can you expect using the internal attenuators?
Attenuation (dB) 0.0 -10 -20 -30
Line Level (Vrms) 2.0 0.6 0.2 0.06
Why not just use the digital volume control?
One reason not to depend on the digital volume control is that Slim Devices audio players are driven by software. There is always a risk (however small) of a software defect that causes the analog output to go to full levels by accident. This would result in the potential speaker or hearing damage if the levels are not matched.
Reducing the volume on the Transporter or Squeezebox occurs in the digital domain before the DAC. If you have to keep the volume very low to "fix" the line level mismatch, you are losing dynamic range and SNR.
An owner has tested Squeezebox audio performance to show the impact of operation in the low end of the digital volume control.
The Squeezebox head designer recommends attenuation for matching line levels to input sensitivity, and reserving the digital volume control for regular day to day listening control.
Practically speaking, however, if a mismatch is small (e.g. .5-1 dB), you might elect to use the Preamp Volume Control in the SlimServer GUI. This setting provides a fixed upper limit on the volume control range. While not recommended because it is effectively the same as using the volume control, a small mismatch is not going to risk hearing or speakers and maybe more convenient than adding small fixed attenuators. An alternative is to simply live with the small mismatch especially if there is headroom in the amp beyond published specifications. Some may choose a small attenuator over the Preamp Volume Control to ensure SNR is maintained.
Lite
tester. Visst går skalan för volym till 100 (jag är inte hemma och kan titta efter)? Mao testerna är gjorda långt ner på skalan. Under den nivån man vill vara efter en analog dämpning. Skulle man inte då kunna dra den försiktiga slutsatsen att - rätt dämpat och inställt så är problemen med den digitala volymregleringen under hörbarhetströskeln?