Hi,
I have a Rotel RC 1080 preamp going into a Quad 606 preamp
Here is the Rotel RC-1090
Quad 606 power amp
Quad 606 Power Amplifier Specification
Power Output: 140 watts per channel (8 ohms)
Distortion: < 0.01%
Input Sensitivity: 500mV
Input Impedence: 20Kohm
Crosstalk: -100db (100hz), -85db (1 khz) and -65db (10khz)
Hum and Noise: 105db
Voltage Rating : 220-200V AC (110-120V via simple power board modification)
Dimensions (WxHxD): 321 x 140 x238 (mm)
Weight: 12kg
The preamp out is 1v and the power amp input is 500mv
What level attenuator would I need to buy to match the preamp to the power amp
-10db or -20db or some other figure?
Thanks
Lee
I have a Rotel RC 1080 preamp going into a Quad 606 preamp
Here is the Rotel RC-1090
Quad 606 power amp
Quad 606 Power Amplifier Specification
Power Output: 140 watts per channel (8 ohms)
Distortion: < 0.01%
Input Sensitivity: 500mV
Input Impedence: 20Kohm
Crosstalk: -100db (100hz), -85db (1 khz) and -65db (10khz)
Hum and Noise: 105db
Voltage Rating : 220-200V AC (110-120V via simple power board modification)
Dimensions (WxHxD): 321 x 140 x238 (mm)
Weight: 12kg
The preamp out is 1v and the power amp input is 500mv
What level attenuator would I need to buy to match the preamp to the power amp
-10db or -20db or some other figure?
Thanks
Lee
An attenuator is not really needed. The preamp can drive the amplifier into clipping,
so just use the volume control within its normal working range, up to about 2/3, or less.
so just use the volume control within its normal working range, up to about 2/3, or less.
Last edited:
I also agree with rayma, it will work, try it and see, although I have found with a quad 405 (also 0.5v) that volume control at quieter levels was difficult with a sensitive preamp output. In the end I modded the amp so it had a 1.25v sensitivity and it made a big improvement to controllability (also reduced noise)
If you do decide to try attenuators, get 6dB ones suitable for 20k input impedance.
Install them at the power amp end of the cables, not at the preamp end.
If you want to make your own, just add a series 20k resistor at each amp input socket.
Install them at the power amp end of the cables, not at the preamp end.
If you want to make your own, just add a series 20k resistor at each amp input socket.
The resistor values for a -6 dB L-pad are not generally too advantageous. 10-12 dB tends to give a more suitable combination. Maybe 4k7 + 2k2.
Power amplifiers may exhibit degraded distortion performance when just using a series resistor, so I wouldn't recommend that.
Since the preamp isn't the last word in output noise anyway and digital sources tend to be quite hot, I see little problem with 10-12 dB of attenuation. (That's still a total 41-43 dB of gain.) 20 dB probably won't be necessary unless you have very sensitive speakers. But even that would still allow a CD player (2Vrms) to drive the power amp beyond clipping levels.
Power amplifiers may exhibit degraded distortion performance when just using a series resistor, so I wouldn't recommend that.
Since the preamp isn't the last word in output noise anyway and digital sources tend to be quite hot, I see little problem with 10-12 dB of attenuation. (That's still a total 41-43 dB of gain.) 20 dB probably won't be necessary unless you have very sensitive speakers. But even that would still allow a CD player (2Vrms) to drive the power amp beyond clipping levels.
Last edited: