Audiophilepure

https://www.headfonia.com/violectric-hpa-v324-review/

Now we get to the good stuff – the nice VU meters! They’re nice to look at as they dance in tune with the music, but they also serve an actual purpose. On the HPA V324 they measure the incoming signal. Some power amps have output power meters and many folks quickly realize that their amp is coasting at under 1W so the meters pretty much stay in place.

With the Violectric amp, we first need to adjust the input sensitivity of these meters. On the back panel, we see the DIP switches, which can reduce the input sensitivity of the meters. Your DAC tech spec should show how hot the output signal is. 4Vrms is roughly 15dBU, so flip the appropriate switch up to get an accurate measurement.

If you’re unsure, download a 0dB noise file, play it on Foobar2000, or some other player that bypasses the OS mixer and flip the switch so that the needle stays at roughly 0dBU.

The back panel also houses a couple of curiosities. There’s a tuning knob for the VU meter brightness as well as the inputs and outputs. Violectric is advertising that the HPA V324 is also a preamp, so we get outputs and a button which toggles the outputs between true attenuated preamp duty and loop-outs if you want to connect something else in a daisy-chain, like an integrated amp.