[bassboysam]

I found a Pro-Ject Dock Box S Digital for a good price so I decided to give it a try.  According to Pro-Ject
"Dock Box S Digital uses digital audio signal from Apple devices to avoid signal degradation inherent to the analogue outputs.  
All signals are directly transferred to 24bit/192kHz highend D/A converters by Cirrus Logic. Additionally there Is a SPDIF digital output (RCA), that can connect to outboard D/A converters or digital inputs of home cinema processors.  
Dock Box S Digital is certified by APPLE and can be used with all equipment that uses 30-pin connection."
 
 
When I plugged everything in, I read the manual and it states that the ipod Volume should be set on full.  Adjusting the ipod volume seems to also adjust the RCA output signal from the dock box. 
 
My question is, if the dock box is bypassing the internal iPod DAC, shouldn't the volume on the ipod not have any impact?  Is it possible that this box bypasses the DAC but not the amp in the iPOD?  in which case does that defeat the purpose?
 
 
here is the link to the manufacturer's website.
http://www.box-designs.com/main.php?prod=dockboxsdigital&cat=source&lang=en

 

[thrand1]

Quote:

I found a Pro-Ject Dock Box S Digital for a good price so I decided to give it a try.  According to Pro-Ject
"Dock Box S Digital uses digital audio signal from Apple devices to avoid signal degradation inherent to the analogue outputs.  
All signals are directly transferred to 24bit/192kHz highend D/A converters by Cirrus Logic. Additionally there Is a SPDIF digital output (RCA), that can connect to outboard D/A converters or digital inputs of home cinema processors.  
Dock Box S Digital is certified by APPLE and can be used with all equipment that uses 30-pin connection."
 
 
When I plugged everything in, I read the manual and it states that the ipod Volume should be set on full.  Adjusting the ipod volume seems to also adjust the RCA output signal from the dock box. 
 
My question is, if the dock box is bypassing the internal iPod DAC, shouldn't the volume on the ipod not have any impact?  Is it possible that this box bypasses the DAC but not the amp in the iPOD?  in which case does that defeat the purpose?
 
 
here is the link to the manufacturer's website.
http://www.box-designs.com/main.php?prod=dockboxsdigital&cat=source&lang=en

 
When using the RCA outputs, the Project is doing the decoding using its own DAC, then using the volume control in some way to attenuate the line level signal generated by the DAC process. This is a different signal than the one you are used to from the amp in the iPod- there is probably some information in the signal extracted from the iPod that the Project box uses to raise or lower the signal level. So it is in all likelihood bypassing the DAC and amp in the iPod so that it can perform the DAC process and volume control the line out signal generated by the DAC.
 
This use of the volume control is probably for cases when the user connects the Project to something like a power amp with no volume knob. Ordinarily the signal output from a DAC is at a fixed level, so without something to attenuate it you would get a 100% full volume blast...so that's why the Project can control the volume out of the RCA jacks.
 
The reason they suggest putting the volume to max is in cases when you do connect the Project's RCAs to something with a volume knob like a pre-amp. In this case, you don't want two volume controls "competing" with one another, so they are suggesting you set the volume to max on one device (the Project box) so you can control it through another one (your pre-amp).
 
If you connect the Project box to an outboard DAC/receiver using the S/PDIF out port, then the iPod DAC AND volume control should be bypassed and make no difference on the sound...might be worth testing if you can.

Again, a lot of this is just based on what I've seen from docks in the past...might be worth sending an email to Project to see what they have to say as well.

 

[bassboysam]

Hmmm very interesting. Yeah I'll ask Pro-ject if they can clarify. Compared to my older pro-ject dockbox which was not a DAC this new one sounds cleaner and less muddy in the bass.

 

[HereticArchitect]

Hi, any updates on this subject?