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Input Sensitivity/Impedance on a receiver, what in the world does it mean?

16K views 11 replies 10 participants last post by  roosters 
#1 ·
Hello folks,


I spent quite a bit of time online trying to locate an article that would educate me on how to interpret input sensitivity/impedance figures found on the specs sheet of a receiver but I came up empty. I have no idea what those numbers should mean to a potential buyer like me who is not an expert in the audio field.


Normally, I wouldn't worry too much about it. However, I came across two receivers that had fairly different numbers.

Pioneer 1020: 300 mV/47 kΩ

Marantz 1601: 130 mV/50 kΩ



Does anybody know if a higher number is necessarily better or does it even have a significant impact on the overall performance of a receiver?


Thank you in advance.
 
#2 ·

Quote:
Originally Posted by ma34 /forum/post/19270990


Hello folks,


I spent quite a bit of time online trying to locate an article that would educate me on how to interpret input sensitivity/impedance figures found on the specs sheet of a receiver but I came up empty. I have no idea what those numbers should mean to a potential buyer like me who is not an expert in the audio field.


Normally, I wouldn't worry too much about it. However, I came across two receivers that had fairly different numbers.

Pioneer 1020: 300 mV/47 kΩ

Marantz 1601: 130 mV/50 kΩ



Does anybody know if a higher number is necessarily better or does it even have a significant impact on the overall performance of a receiver?

Thank you in advance.

OK I'll give it a try..


The mentioned specs are for the high level analog inputs, and simply mean the input level (RMS volts) required for the preamp/amplifier signal chain to output its rated power. The lower the number the more gain the internal circuits has to step up the level, but the differences between 130mV and 300 mV would be nil to the user. For the 130 mV input the volume control gain may be turned down slightly more, note that most source components which output analog signals such as a CD or DVD player their usual output levels are about 2V. So there is plenty of operating margin.


Regarding impedence 47K and 50K Ohms both are essentially the same and are considered as high impedance.


Just my $0.02...
 
#3 ·
Just to add to what he said, and to answer your question, it's a totally unimportant spec for receivers. And will be pretty similar among receivers.


For power amps, it can make the difference between being able to reach full power with your setup - but you did not ask about power amps



Just to be complete, if you ever do look at power amp specs, you may see gain listed rather than input sensitivity. It's the same info, just presented in a different way. I believe a gain of 32 dB is about the same as an input sens. of about 1 Volt (too tired to verify this though
 
#4 ·
Thank you both. From your responses, I gather this should not be a determining factor in deciding on a receiver. With that said, I'd like to go back to M Code's reply for a quick second. For comparison purposes, does it mean that Marantz needs lower voltage from an analog signal to output its rated power? If yes, then I'm afraid I don't understand "The lower the number the more gain the internal circuits has to step up the level".


Good thing I mentioned upfront that I wasn't knowledgeable in this area...



G'night.
 
#5 ·

Quote:
Originally Posted by ma34 /forum/post/19271669


Thank you both. From your responses, I gather this should not be a determining factor in deciding on a receiver. With that said, I'd like to go back to M Code's reply for a quick second. For comparison purposes, does it mean that Marantz needs lower voltage from an analog signal to output its rated power? If yes, then I'm afraid I don't understand "The lower the number the more gain the internal circuits has to step up the level".


Good thing I mentioned upfront that I wasn't knowledgeable in this area...



G'night.

He's right. Say max power requires 50 volts peak. If input sensitivity was 1 volt, the overall gain from input to amp output would be a factor of 50. If input sensitivity was .5 volts, the overall gain would be a factor of 100.


Generally speaking -


* High gain has the advantage of compatibility with more devices (for receivers, gain should really be somewhat standardized, for amps there's a pretty wide range)

* High gain has the disadvantage of reaching the desired output level with less signal; electrical noise, always present in electronics, will interfere more with the input signal as it's at a lower level; in other words, it's assume noise will be more or less constant so a higher input signal to the amp/receiver is less affected by it


Going back to talking about receivers, so called "consumer" line level should be somewhat standard, about .3 volts average. Receiver inputs are designed for this signal level. So the spec should not tell you much of interest. In today's digital age, a lot of people will never hook up an analog device making this discussion a lot less interesting
 
#6 ·
So if a receiver has an input sensitivity of 200mV. A CD player will have to put out at least 200mV for the receiver amp to reach full power?
In order to use an external amp with an input sensitivity of 1V, with receiver preouts, the receiver preouts need an OUTPUT sensitivity of at least 1V?
 
#7 ·
what your asking is very complicated but is important. you need to match equipment. and just because stuff has the same input/output connections by no means they will sound great together.
 
#11 ·
I realize I'm a few years late to the party here, but to touch on the difference between input impedance numbers. Basically, the lower the impedance on any analog input or output, the better. Anyone who owned an Eclipse CD player with only 55ohm output impedance could attest to the sound stage being much larger that the competitors. However, 47k Ohms vs 50k Ohms, plus the fact that you shouldn't be expecting audiophile amplification from most receivers means this measurement is virtually insignificant.
 
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