New (used) preamp 4 911 mk3

[Talk2me]

I need something to help me untill I decide what I want to do and go with my system afte I sold my 089. So, I got a incredible deal on a Cary CPA-1. I know very little of impedence matching between amps and preamps. I do know that I need help.. I have been led to believe the Burmester sounds best through balanced XLR. Here are the Cary's spec's:

Preamplifier Inputs 1 pair balanced XLR connections
6 pair single-ended RCA connections
Preamplifier Outputs 1 pair balanced XLR connections
2 pair RCA connections
Controller Connectors 1 - 3.5mm “mini plug” jack for IR input
3 - 3.5mm “mini plug” jack for trigger out
RS 232 full remote configuration interface
Volume Control Range 63.0 dB
Gain Resolution 1.0 dB steps
___Input Impedance 100k Ohms on RCA
___200k Ohms on XLR

Rated Output RCA - 1 Volt (8 volts maximum)
XLR - 2 Volts (16 volts maximum)
THD+N <0.001%
Frequency Response + 0.1 dB from 5 Hz to 100 kHz
Signal-to-Noise Ratio 120 dB "A" weighted
Voltage Gain 26.8 dB

[cmalak]

Jim...I couldn't find anything on the CPA-1 from Cary's site. Do you know what it's output impedance is? And do you also know what the input impedance is of the 911 mk3? You want a minimum of 10:1 preferably even higher ratio between the input impedance of your amp and the output impedance of your preamp. If you can find a Stereophile review of the CPA-1 with John Atkinson's measurement section, even better, because that will give you a sense for how the output impedance of the preamp changes over the frequency spectrum. What I would do is take the max output impedance (as opposed to the nominal rating) and multiply it 10X. If that number is less than the rated input impedance of the 911 mk3, you ae fine from an impedance matching perspective. Ofcourse this does not guarantee sonic synergy between these two components but at least it will give you confidence there is not an electrical mismatch.

[Talk2me]

Thanks, but I have no info on the Burmester impedence out/input numbers.

[wizard]

911 mk3 has very low input impedance - 2k ohm balanced and 15k ohm unbalanced.

For best impedance matching use 12X on the output impedance.

It's easy to hear if one have a impedance mismatch - little or no bass at all.

[Tonepub]

Just plug it in and see how it sounds....

[Anatta]

The input impedance of the 911 is 1kOhms, you need a pre with a very low output impedance.

From Stereophile measurements of the Cary SLP 05:

"The SLP 05's output impedance is specified as a usefully low 400 ohms. However, I got significantly higher values for the unbalanced output of 1500–1600 ohms in the midrange and treble, rising to 3400 ohms at 20Hz, with similar if slightly lower figures for the balanced output. The Cary preamp needs to be used with power amplifiers having input impedances of 10k ohms or greater if the bass is not to sound a little lean. "

[Talk2me]

Originally Posted by tonepub

Just plug it in and see how it sounds....

That is too easy.... If it sounds "OK", how do I know if it could sound better? Or just forget impedance matching and just go by, " Hey Nigel, thee old bird, sound right by me!"

[joeinid]

You never know until you try ... Keep us posted.

[Tonepub]

Originally Posted by Talk2me

That is too easy.... If it sounds "OK", how do I know if it could sound better? Or just forget impedance matching and just go by, " Hey Nigel, thee old bird, sound right by me!"

That's what system synergy is all about. If you have the preamp, plug it in, you'd know the answer by now.

[Talk2me]

Originally Posted by tonepub

That's what system synergy is all about. If you have the preamp, plug it in, you'd know the answer by now.

I am being pro-active, as I have not recieved it from UPS yet.