Correct Connnection of Pre Amp/DAC to Amp

[alex30]

Hi,

I apologise for repeating this post but I am not sure I posted in the correct place first time around (Computer based audio)

I do hope that some kind soul will put me right as I am confused.

I want to connect a Peachtree Decco 2 (basically the same as the iDecco but without the ipod dock) to a Cambridge Audio Azur 640A mark 2 Amp in order to use the Decco as a pre amp and DAC to feed the Cambridge. The Decco Amp is 40 watts per channel whereas the Cambridge is 75 watts per channel.

So my first question is will the Decco act as a preamp for the Cambridge given that the Decco does have a pre amp circuit? If so do I simply connect the Pre Out of the Decco to the Aux In of the Cambridge? I tried this and it resulted in a variable output form the Decco with the volume knob fully functional, which leads on to my next question - Where should I put that knob , quarter volume, half, three quarters or full?

On the other hand there is a Line (fixed) Output from the Decco so would it be better to use this?

What are the benefits and disadvantages of the two different outputs, Pre Out and Line Out ? And is the Aux In of the Cambridge the correct connection to use?

Thank you in advance.

Regards Alex.

 

[ID.]

The problem is that you can't use just the power amp stage of the Azur, so by using pre-out you are going through two preamps, so I'm not really sure what to advise about settings for the volume knobs. It all depends on the output voltage of the Decco. The 40 watts refers to the maximum output of the Decco's power amplification, and doesn't apply to the signal taken from the line out or pre amp output.

Apart from the potential risk of overdriving, the thing that would put me off doing it this way is that it seems like it passes the signal through an unnecessary amount of circuitry and might present a more degraded signal, but I'm just guessing. When you use the Decco as a preamp (called control amps in Japan), the whole point is to be able to control the volume from the Decco. Preamps are normally connected to power amps (amps without a volume control) or active speakers (speakers with power amplification built in).

The standard connection would be Line Out to the Azur. Aux In is fine. You could even connect it to the CD input if you wanted. This is how I'd try to do it. You would still get the benefit of the class A output for the Decco's DAC, but you would be skipping the tube preamp stage, so wouldn't be getting the effect of the tube on sound. The ideal power amp would probably be Peachtree's own power amp.

http://www.peachtreeaudio.com/peachtree220-power-amplifier.html

If I really wanted to use the Decco as a preamp I'd be looking to pair it with a power amp (or a integrated amp that lets you use just the power amplification stage) or some active/powered speakers.