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silveira neto Posts

microKORG with an iPad Pro

The KORG microKORG is a great synthesizer and vocoder launched in 2002. It does not feature a USB port but you can use a interface to convert MIDI to USB and use it to play with an iPad Pro (4th generation) launched in 2020.

This is a setup that I use to compose or play in the bedroom in headphones. I try to be not have a lot of cables and to be easy to set it up and down.

MIDI to USB: I’m using a LiDiVi MIDI to USB interface to connect the IN and OUT MIDI ports from the KORG into a USB hub. If you are looking for a MIDI to USB interface this one is fine but has extremely bright, blinking and annoying LEDs I will probably cover them with black tape later. I suggest going with a more discreet interface (although I like the colorful cables).

USB hub: I’m using a QGeeM 8-in-1 USB hub. A USB hub is not really necessary as I could use a USB to USB-C converter and connect the MIDI to USB interface directly to the iPad and enjoy their 4 speakers. However I want to use headphones. I have tried Bluetooth headphones but they introduced a unbearable delay between pressing the keys and the sound.

It is optional but convenient to power the USB hub so it can keep the iPad charged. Unfortunately you need the MicroKorg using either a DC 9 Volts AC adapter or six AA batteries. I’m using batteries to avoid having yet another cable. I’m my experience the batteries last quite a while.

The MicroKorg is full-fledged synthesizer with the capabilities of understanding MIDI that make it capable to control softwares on a iPad.


  • 3 octaves
  • Big buttons for octave shift up and down
  • Pitch wheel
  • Mod wheel
  • Small form factor
  • While not used as a MIDI device you can still use it as an standalone instrument.


  • You have to use an external power source or batteries.
  • A personal preference but I find that you have to press the keys with a little bit too much force in order to get the full velocity.

I’m currently using it with the KORG Gadgets 2 app but it will work with software that accepts MIDI input.

Mackie CR3 Studio Monitors repair log

Problem: No sound coming out of the speakers. In the beginning the sound would come and go. Then the sound stopping became more frequent until being completely mute.

What is working: The headphone output is working fine. With it I could test that the auxiliary input (front panel) is working fine too. Left and right RCA inputs are working. Left and right left and right  6.35 mm (​14 inch) inputs are working.

From the outside the only problem seems to be the speaker.

The cause: After some research I found that this is a common issue for Mackie CR3 Studio Monitors. The root cause seems to be the amplifier chip TDA7265. This chip works fine initially but after some months or years it starts malfunctioning sending a mute signal (output 5) to the board which mutes the speakers. This mute signal should only be triggered when a headphone jack is inserted however in the malfunction the signal is sent continuously.

Solution: cut the ping 5 with small cutting pliers. This stopped the mute signal but also removed the feature of muting the speakers when headphones are plugged. As this worked for me I could replace the TDA7265 chip (around $5) but I will not do that now.

Alternatives: here are some alternative solutions that did not work for me but I read that worked for some.

  • Blowing air into the inputs to remove dust and debris.
  • Quickly removing and inserting and inserting the auxiliary jack.
  • Quickly removing and inserting and inserting the headphones jack.

Conclusion: Don’t buy these speakers. I got it in a bundle deal with some audio gear I bought about three years ago. Speakers should not fail in only three years. The design of this thing is flawed. It heats too much and components start to fail. The amplifier chip seems to be a common issue but when researching this I found switches, I also saw switches, diodes, capacitors, and resistances failing. Even after I fixed it I was hearing some cracking noise in some frequencies.

Supplementary materials:

Vypyr VIP 2 amplifier clean patch by-pass step by step

  1. Turn the Vypyr VIP 2 on.
  2. Set the inst/stomp knob to BYPASS.
  3. Set the amplifiers knob to Classic.
  4. Press the amplifiers knob to select the clean (green) mode of the classic amplifier.
  5. Press the inst/stomp knob. You are now in the edit mode and the edit mode led (red) is on.
  6. Turn the delay feedback knob to zero.
  7. Turn the delay level knob to zero.
  8. Turn the reverb level to zero.
  9. Press the inst/stomp knob again. You are now out of the edit mode and the edit mode led is off.
  10. Turn the pre-gain knob to the middle.
  11. Turn the low knob to the middle.
  12. Turn the mid knob to the middle.
  13. Turn the high knob to the middle.
  14. Turn the post-gain knob to the middle.
  15. To always have this patch when the amplifier starts, save it to the bank A preset 1 (red). On the instrument type column of buttons, press and hold the first button (A electric 1) until the red led blinks once and comes back on.

Adapted from Vypyr Tips/Tricks/FAQ at the Peavey forums.

With this patch you can use thes Vypyr VIP-2 as a regular amplifier with other gear inputting directly to it.