I've just noticed. .theres a hum in my sp-404 when the digits on the display are higher..

eg, 96 hums louder than 1


wtf! anyone else get this? (choose a sample with say 120bpm . . then set the mfx to 1 and hold down/release the mfx button to see if you notice a difference...

wow, gotta check this out- I have had problems in the past with a humming sound, but i think its from the tt.

It does happen. May depend on what power you're using. If batteries, it gets worse as they run down. It's even more noticable on the Mic input, even on the ac power, if you have to turn the mic trim right up. If you're using rechargable batteries, I find Alkaline ones are best, because they're a full 1.5volt each. Other kinds are around 1.2volt.

The main electronics board and the one at the top with all the LED's and pads are right next to each other like a sandwich. I tried putting a screen (big sheet of copper foil insulated in a laminator and wired to the ground screw at the back) between the boards, but it didn't make much diff'.
I think its a design fault - the analog pre-amps are getting interferance from all the current the LED's take. You can reduce the amount the LEDs work to some extent with a setting (see manual) - but you may miss the visual cues they give.

I don't find the noise much of a problem provided I can get the levels as hot as possible. If recording, make sure the pad Level control is max at 127, absolutely no point recording with this level less than that. If it was going to clip, it'd happen in the circuits before this level control 'cause it's digital and has to be after the analog-digital converter.