More powerful amp - lower volume?

[Benham]

Hi

Thank you for accepting me in this forum.

This might be a stupid question, I am really not into the technical and nitty gritty stuff.

I have a home theater setup (marantz receiver), which gets extra power from two stereo power amps (NAD C270 and NAD C272 - 120 and 150 watts per channel into 8Ω). I recently upgraded to two more powerful class D amps with these specs: 2x350W @ 8Ω - 2x500W @ 4Ω - 2x450W @ 2Ω (Audiophonics LPA-S500NC).

Now my question is: how come that when swapping the amps to the new ones, that the volume of the speakers powered by the amps are lower than before (around 10db difference)? I had to bump up the gain/trim in the AVR by quite a bit. Is it because the new amps not are delivering the specified power, or is it something else? It might be something obvious and not an issue, but as I said, I am not into the very technical stuff

If you could explain in layman terms it would be much appreciated. Thank you in advance!

 

[Blumlein 88]

Amps have different levels of gain. With some you put in 1 volt and get 100 watts. With others you put in 1 volt and get 200 watts or 50 watts. Yes you can have a 400 watt amp that needs more voltage input to get its max output.

So if your old amp needed 1 volt for 50 watts, and your new 350 watt amp needs 2 volts for 50 watts it will sound lower in volume even though with enough input signal it is still a true 350 watt amp. So bumping the gain or trim level should do what you want. It does not indicate any issues with the amps.

 

[radix]

I think that LPA-S500NC is closer to 200wpc at 8 ohm (based on the THD graph). AFAIK, the Hypex NCxxxMP amplifiers at 26 dB gain. But I think it wants a full 2.35V for max power.

The NAD is rated at 29 dB gain. The spec sheet says the input sensitivity is 1.3V for rated power.

As Blumlein said, you might just need to bump the gain on the Marantz.

 

[Benham]

Thank you for the swift answers, it does make a lot of sense. No need to worry then! Thanks again