2. amps-preamps
  3. 1048834962

Passive Preamp Impedance Compatability Issues


I am looking to add remote-control volume capability to my audio system which includes a NAD 314 integrated amplifier. I've been told that a passive preamp connected between the pre and power sections of the 314 would be the best solution. I am considering the Creek OBH-10 and the Velleman K8022.

The Velleman (www.velleman.be) is substantially less expensive since it is a kit product, but I've never seen any reviews of its performance. My major concern with the K8022 is related to its impedance ratings input: 5Kohm, output: < 2.5Kohm. This is quite a bit lower than the preamp section of my NAD 314 input: 20Kohm, output: 220. The Creek has an impedance of input: <20Kohm, output: 0-20Kohm.

Can anyone tell me how these impedance figures would reflect on the compatibility between a passive preamp and my integrated amplifier?

Thanks, Jeff
melodynelson
inpepinnovations1e75
395 posts
 
Should work out OK with the Velleman. The out of the pre is 220 and the input of the K8022 is 5K which is more than the min. 10:1 ratio usually stated for good performance. same with the in to out ratio (at all positions except in the max. attenuation)for the power amp. and K8022.
melodynelson OP
1 posts
 
The two inputs into the K8022 would be my CD player (Harman Kardon HD7500 with an output level and impedance of 2.0V @ 10k ohms) and the preamp section of my NAD 314 which would be serving as my phono preamp (output impedance of 220 ohms).

Tha input impedance of the power amp section of my NAD 314 is 10K ohms.

Thanks for your help! Jeff
newbee
4,767 posts
 
The impedence values of your pre amp and amp are on the marginal side and much would depend on your cable choices and lengths. Have you thought about just putting it in the tape loop - that way the impedences values & gain would be taken out of the equasion. As a further benefit you can simply switch it out of the system by flipping a switch. I use a Creek in the tape loop of my ARC pre and it works just fine.
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