A Disappointing Hum From My New Keyboard Solved - Quite a Journey!

Palmer Wupper - Line Isolation Box Passive. Unbalanced Jack in, Unbalanced or Balanced Jack Out.

[@alfredpirotta4944]

Hi Anton, For years, I've travelled on the road of master keyboard, audio interface, laptop and amp. For a clean stereo image (for rotary simulators, pads etc.) I have used a small PA or powered speakers. On the laptop, I'd run a DAW but these days use Gig Performer which is an amazingly stable and reliable host. With such a setup, that has many advantages for me, earth loops were the first issue that arose between the components and seemed to scupper whole concept at the very outset. The simple answer was to get a Ground (or Earth) Loop Inhibitor (or isolator). These typically come in L and R channels and use RCA plugs to the audio output socket/s and then plug into your amp or desk. They can easily be had for around a tenner and totally remove the hum issue. Most of what's inside is just a big capacitor per channel.

[@S.T.G.]

So this unit can isolate the grounds of the two sides and, therefore, break up the ground loop and can also convert an unbalanced signal into a balanced one, which may also contribute to lower noise levels, especially, in case of a long cable run. However, unlike a typical di box, it won't attenuate the signal from line level to microphone level and won't perform an impedance conversion due to its 1:1 transmission ration (0 dB gain).

[@AntonBrowne]

Well said. Shame I needed to get one but hey!

[@aTouchoClass]

Doesn‘t the CP88 have XLR-outs anyway? Why the need for a DI? BTW congrats for your purchase, it‘s a really nice instrument! I had one for about a year but had to get rid of it eventually, didn’t quite fit my needs. No humming for me that I remember, though.

[@AntonBrowne]

Thanks. Yes it does have XLR outs but I use the mono jack out. I am now very happy with it so far.

[@aTouchoClass]

@@AntonBrowne Happy to hear that. And, looking forward to hear the CP88 in one of your hopefully soon to come singing & playing performance videos, featuring maybe the new Shure, if I may kindly suggest ;)

[@TheWooTubes]

I'm an IT geek, so I was interested in your solution for a problem I don't have (yet.) Then KZbin showed me this kzbin.info/www/bejne/paLUiZKHYqitaK8si=q7Qxr2ydQF1fPwyz Is the Roland a modelling amp? There's quite a bit of discussion too.