Boosting low keyboard audio input levels

Hi all-- This is barely related, but given the community expertise I thought I’d ask… My main board is a Kurzweil PC88. It has unbalanced audio out, but the levels are just always really low. I’ve actually had two of these boards, and they’re both the same… really low audio signal.

When I ran my boards straight into a Roland KC-500, it had plenty of power to boost the Kurz and turn my other boards down to minimal. The sound was nice and full. Running it into my audio interface so I can pipe it through Cantabile, though, it sounds pretty quiet and thin. I’ve tried to stage all the gains to crank up the levels to pretty close to unity overall, but the sound is… well, it sounds like it’s underpowered and I’m boosting the heck out of it. I threw a DI inline, and it didn’t make any difference. I’m wondering if I need to put a pre-amp or some kind of active boost in before it gets to the interface inputs? I’m thinking about trying the Radial Key Largo as a whole interface replacement, but I’m hoping there’s a less radical solution somewhere.

Any experience with boards that are just too quiet? Any ideas for boosting this thing?


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Hey Jeff,

yes, some of the Kurzweils are notorious for their low output. There seems to be some intentional logic to it - apparently they want to avoid clipping when running complex sounds multitimbrally…

On my PC3, I am using the master effect EQ to boost output by +6 dB - that’s good enough. Also, the PC3 has balanced outputs, so feeding them to balanced inputs adds another 6dB.

Not sure if the PC 88 has a master EQ that you can use to boost the audio?

Otherwise you’ll need to use some form of pre-amping after the PC 88 (if your audio interface doesn’t have the option to adjust the pre-amp level for line inputs).



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Thanks, Torsten-- I’d heard this was a global Kurzweil issue, for sure. I will try the master EQ boost and see what that gives me. Unfortunately, the PC88 doesn’t have any global EQ or volume settings (aside from the hardware slider) that I’ve been able to find.

Does anyone have a recommendation on a relatively inexpensive pre-amp (primarily for piano sounds) for live use?


I have a PC 88 also. I have two ways of boosting the output. The first is to run it through the microphone input of a Mackie 4 channel mixer. The second is to use the headphone output on the PC 88 instead of the regular output. The headphone output puts out a lot more sound I discovered. Sometimes I do both.

  • Paul
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