Airport Express + Amp only. Need Pre-Amp?

[lpennock]

I have one airport express connected to a Sony ES receiver, and another connected to a Classe Integrated Amp, and all is well there. I also have outdoor speakers connected to an Adcom amplifier that used to be plugged into the Sony receiver using it's 2nd room functionality. For a variety of reasons I have separated this out and attached the Adcom amp. directly to a new airport express. Physically, the amp is with other indoor equipment, and there is a resistor based volume control outside near the speakers designed to control the volume post-amplification. Here is my concern, without a pre-amp, I believe the equivalent airport express output to the amp is minus zero db on a pre-amp (or +10 or what have you on pre-amps that don't use the minus db designation). In effect, am I sending a signal to the amplifier that is equal to having the volume knob turned up all the way, and then reducing that volume post amplification with the resistor based volume control, and if so, do I risk damaging the amplifier?

 

I can counter this somewhat by using Airfoil, which allows me to turn the signal volume down on the feed going to the patio speaker airport express and then turn the outside control up to achieve the same volume.

 

Or, I can invest in a cheap pre-amp that only needs to do one job: volume. Any suggestions there? Thoughts on this overall scenario?

 

Thanks,

 

-Lewis

 

[shenzi]

It depends on the voltage going into the Adcom amp whether you run the risk of damage. Also you're not doing your speakers any favours, driving them via a variable resistor (you'll be changing the damping factor as you go). A much better option is to put the volume before the amp and get rid of the speaker volume. You could probably use a simple passive volume pot for this, or something more sophisticated if you need a remote. I believe QED used to make something of the sort.

 

[cfmsp]

 

 

http://www.smproaudio.com/produkte/monitor-controller/inano-passiver-lautstaerke-controller.html

 

I think it costs $69 in US.

 

clay

 

 

[lpennock]

Thanks for the suggestion - I tried to find the output voltage of the Airport Express but was lost in a sea of discussions about the power voltage. I didn't know about passive volume controls.

 

I guess it would be best to put a passive volume control before the amp, something like what clay suggests but with RCA in/out, and then aim to keep the outdoor resistor based volume nearly all the way up. Right now it's doing a lot of, um, resisting on a full wattage high volume signal coming out of the Adcom (the amp also gets quite hot). I still like the control it offers, being right outside, however, so I'll keep it in line.

 

Thanks again for the replies.

 

-Lewis