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Total System Gain Question

I am considering an amp with 25dB of gain and 575mV input sensitivity for rated minimum output, and considering a preamp with 18dB of gain. So total system gain would be 43dB. My speakers are 88dB efficient.

Is too much gain for a 2V line level DAC source? I don’t know what the input sensitivity of the preamp is. I worry I’ll be stuck in the bottom (non-linear) portion of the volume pot due to the total gain ...

I don’t have a feel for this since I’d been using an integrated amp forever.
greg7
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cleeds
5,949 posts
 
pragmasi
That’s a lot of gain, works out to around 2500W into 8Ω at full volume. A rule of thumb is that every 6dB of gain doubles the voltage, if you know Ohm’s law you can work out the rest.
If you ran a unity gain (0dB) preamp into that power amp it’d need to be capable of 150W into 8Ω, or with a preamp with 6dB gain around 600W
You've confused gain (and input sensitivity) with power output. They are two completely different things. There's no way to calculate power output in watts from the information the OP has provided.
pragmasi
212 posts
 
You’ve confused gain (and input sensitivity) with power output. They are two completely different things. There’s no way to calculate power output in watts from the information the OP has provided.
Input sensitivity, gain and power output are all related mathematically and you can work out one from the others if you assume a certain loudspeaker impedance.
I didn’t say the system would be capable, just that an 8Ω speaker driven by the maximum output voltage would need 2500W from the amplifier and need to be able to tolerate it.

twoleftears's avatar
twoleftears
5,318 posts
 
Short answer: what this means in practical terms is that you'll very likely only be using your preamp's volume control at the lower end of its range.
millercarbon's avatar
millercarbon
12,531 posts
 
https://www.amazon.com/Complete-Guide-High-End-Audio/dp/0978649362/ref=sr_1_2?crid=1HQWAOMTH56KK&...   

In case that doesn't work 

https://www.youtube.com/watch?v=4xgx4k83zzc
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cleeds
5,949 posts
 
pragmasi
Input sensitivity, gain and power output are all related mathematically and you can work out one from the others if you assume a certain loudspeaker impedance.
There's no way to calculate power output in watts from the information the OP has provided. You simply don't know what you're talking about.

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