Hifiberry DAC+ ADC input gain

Using Zynthian
#1

Hi,

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!

Cheers,
Arnaldo

1 Like
#2

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.

Regards,

#3

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.

Thanks!

#4

Resolved!

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.

Thanks!
Arnaldo

4 Likes
#5

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

Thanks

#6

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.

Cheers

1 Like
#7

Ok, thank you.

#8

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.

#9

Many thanks for feedback :+1: