cat2

2008-03-25, 15:13

Hi I am getting an old Cyrus Q Power with the specifications below. My concern is of plugging it straight into the line out of the Squeezebox 3(soon to be a Duet) I found the wiki page http://wiki.slimdevices.com/index.cgi?ConnectToPowerAmp which states that the squeezebox3 will be 6 Vpp/2.1 Vrms but I am lost on how this applies to the amp specified below. I assume I need attenuators and ideally would like to have it sorted before I plug it in.

Does anyone understand this stuff and can tell me what I need, my current attempt at how it works is (first time I have used the log button on the calculator :-)) ...

SQ3 2.1v (max volume)

Cyrus Q 380mV (max)

so far looks like things are going to blow up,

dB = 20 * log ( .380 / 2.1 ) = -14.85

This will allow the full volume on the SQ3 to be the max the amp can handle. I assume a attenuator something like http://www.amazon.com/Harrison-Labs-Line-Level-Attenuator/dp/B0006N41B0/ref=sr_1_1?ie=UTF8&s=electronics&qid=1206482411&sr=1-1 but I will need 15 would be what I am looking for? Can I just daisy chain them together, i.e plug a 3db into a 12db to get 15db ?

Cyrus Q Power

Specifications

Continuous Power - 50W/CH (both driven into 8 Ohms) 70W/CH (both driven into 4 Ohms)

Frequency Response - -3 dB at 1Hz and 80kHz

Current - 30 Amps peak to peak

Sensitivity - (RCA input) 380mV (for 50W stereo into 8 Ohms)

Input impedance - 10Kohm (RCA)

Output voltage - 380mV (Chain out)

S/N Ratio - 110dBA

My speakers

M31

Specification

Enclosure type 2-way reflex loaded

Frequency Response (+/- 3dB) 65Hz-20kHz

Sensitivity (SPL/M @ 2.83V) 88dB

Cabinet Volume 7l

Impedance 8 Ohms compatible

Recommended Amplifier 25-75W

Dimensions (mm) 225 x 170 x 280

Included Accessory n/a

Optional Accessory1 Stancette

Optional Accessory2 n/a

Does anyone understand this stuff and can tell me what I need, my current attempt at how it works is (first time I have used the log button on the calculator :-)) ...

SQ3 2.1v (max volume)

Cyrus Q 380mV (max)

so far looks like things are going to blow up,

dB = 20 * log ( .380 / 2.1 ) = -14.85

This will allow the full volume on the SQ3 to be the max the amp can handle. I assume a attenuator something like http://www.amazon.com/Harrison-Labs-Line-Level-Attenuator/dp/B0006N41B0/ref=sr_1_1?ie=UTF8&s=electronics&qid=1206482411&sr=1-1 but I will need 15 would be what I am looking for? Can I just daisy chain them together, i.e plug a 3db into a 12db to get 15db ?

Cyrus Q Power

Specifications

Continuous Power - 50W/CH (both driven into 8 Ohms) 70W/CH (both driven into 4 Ohms)

Frequency Response - -3 dB at 1Hz and 80kHz

Current - 30 Amps peak to peak

Sensitivity - (RCA input) 380mV (for 50W stereo into 8 Ohms)

Input impedance - 10Kohm (RCA)

Output voltage - 380mV (Chain out)

S/N Ratio - 110dBA

My speakers

M31

Specification

Enclosure type 2-way reflex loaded

Frequency Response (+/- 3dB) 65Hz-20kHz

Sensitivity (SPL/M @ 2.83V) 88dB

Cabinet Volume 7l

Impedance 8 Ohms compatible

Recommended Amplifier 25-75W

Dimensions (mm) 225 x 170 x 280

Included Accessory n/a

Optional Accessory1 Stancette

Optional Accessory2 n/a