Hifiberry DAC+ ADC input gain


I’m trying to use Zynthian as an effects processor, connected to my keyboard. It works but the output level is very low, even with the keyboard volume at its maximum level. I know the keyboard output is fine because other dedicated FX pedal works fine.

I’m thinking about changing the config of the input gain from zero to +12db, has anyone changed this default setting. It is done via jumpers on the Hifiberry board.

My Zynthian is a v3 with Hifiberry DAC+ ADC HW 1.2.

Thanks in advance!


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So you have a HifiBerry DAC+ADC “Standard”. This model has a “suboptimal” balanced input. Is balanced your keyboard’s output? Are you using the "balanced mono TRS jack " or the “unbalanced stereo minijack” input?

Anyway, try to increase the gain by 12dB or 32dB with the jumpers setting. It’s well documented in the HB site:

I tried some time ago and it worked.


I’m trying to use the input as described in the Warning (Building a Zynthian Box using an official Kit v3 - ZynthianWiki) but with two mono connectors.

I’ll try to configure the gain and report here if it works.



The alsa mixer settings were right, with high level output, but that gave me a hint and I went checking the FX config, founding low dry/wet output levels.

So the wiring is correct, I have now stereo input with separate standard jacks and there is no need to change the input gain, the default 0 dB is fine for line level.



Hi @Arnie, good to know.
Can you tell me if you

  • Can configure left/right input gain separately
  • If you ever have an electric guitare plugged in and how it works/sounds


Hi @le51 ,

No, the level configuration is the same for both channels.

As for the guitar, I never tried but I have an acoustic-electric guitar, I’ll try it and let you know if it works. Since it has a built in pre-amp, I think it will deliver higher level than a standard electric guitar with passive circuitry - maybe the input gain boost will not be necessary.


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Ok, thank you.

I tested with an electric-acoustic guitar and it seems that some additional gain is really necessary. I didn’t try to change the gain from the default 0 dB but it is clear that some boost is required for such kind of instrument.

Many thanks for feedback :+1: