Underpowered using different usb-cables?

Hi,
so I get very different reactions from using different usb-cables.


and

Both times they are connected to a typical usb-powerplug going into an electrical plug.

With some the device is underpowered and xrunnin’ like crazy. With others there seems to be no problem.
Yesterday I was in the studio with the zynth. It was underpowered and had so many xrun’s that with two miditracks being played through zynaddsubfx the clicking would make it un-recordable. I’ll try going back tomorrow with a different cable to see if there is a direct relation between the x-runs and the power.

Anyone else experiencing this?

Yes, high impedance power cable will limit current and create a potential difference (voltage drop) across the wire. This can result in a voltage at the Pi less than 5V. The Pi reacts by reducing CPU power and hence lower performance. I encounter this with some jumper cables between my UPS and Pi header. I am yet to fix this with thicker cable and better quality crimping. Resistance will increase if there is poor connection and with thinner wire.

Same experience here when using an extension cable.

Always had those problems with very-chinese cables… the worst cable I had had a 1.5V voltage drop at 1.5A.

Since then, I test every single cable I want to use as power cable, and ditch it if it drops more than 0.2V@1A. Better safe than sorry.

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Ok then clearly mini-usb cables do vary a lot in quality and power output. Thanks for enlightening me guys!

Hi, sorry for digging up this old thread; I bought a 5v / 3A usb charger (destined for Raspberry pi3+) but the clicking (little red triangle) continues to bother me, especially when using bass emulation or other ‘heavy duty’ stuff like piano etc.
Can anyone out there advice me (amazon link to be clear) on what cable I should use to go along with my charger ?
Thanks!

RBPi3 has limitations and some engine/presets doesn’t work fine as they consume too much CPU. The only solution for that is changing to RBPi4.
If your are using the official RBPi3 power supply, you don’t see the underpower symbol (red light symbol), and only see the XRun symbol (red triangle) with some combinations of engine/preset, probably you are reaching the RBPi3 limits and should consider changing to RBPi4.

Regards,

Ok thanks, if the CPU is the problem I will have to live with the issues, I don’t like the idea of replacing something I only bought a month ago.
(I drive a car from 1966 :wink:)
At least I can stop searching for a solution and start adapting to the disadvantages that seem to come along.

You don’t need to change “everything” … only the RBPI, that will cost you about 40 €.
There are some people by here that can explain (already did it in some post) how to modify the alucase for fitting the RBPi4. It’s not very difficult indeed … you need a dremmel and 30 minutes :wink:

Regards,

And this will improve the overall performance ? (Speed, end of clicking…)

While I haven’t tried the rpi4 yet, I sure have learned an arrived at the different limitations of the rpi3. Usually when having 2-3 layers without effects everything is fine, however there are expections:

  • OB-x is only with certain presets useable. High possibility of clicking. Zynaaddsubfx 80% of the presets work fine, but some do click.
  • Generally too vast amounts of midi-informtion offer chances of clicking. Think of fast Arps. Or huge chords of 8 notes +. The arturia keystep is grand for the letter, so I’m looking forward to get a pi4 at some point :wink:

Overall performance will improve when using a RPI4 . You will be able to push it further before experiencing x-runs (clicking). The RPI4 also requires a different power supply, a 3A USB type-C. The official Raspberry 4 power supply costs $8 U.S. , check your local price. I bought the 2GB model when they first came out as the 4GB model wasn’t available at that time. The original RPI4s had some over heat problems and I put a small fan on mine to eliminate the problem. I have read improvements have been made to the newer RPI4s regarding the heat issues, perhaps someone who knows for certain can confirm if this is true. When I upgraded, I used my RPI3 to make a second Zynthian using a cheap touchscreen and a cheap USB audio device. It doesn’t have encoders but I use the touchscreen instead. Also, no MIDI ports so I use a USB midi keyboard. You can even just hook up your RPI3 to a HDMI monitor or TV instead of buying a touchscreen and use a USB mouse instead of encoders as well as use midi learn to control your encoders with a USB midi controller keyboard. Most HDMI monitors are too bulky for stage use but work well in a home studio if you have enough space. I would still recommend a USB audio device as they can be found for as little as $5. I recommend one with audio input and output so you can make use of the input with the Zynthian. All you will need to do is change your hardware settings in the web configuation tool to match your custom setup. Of course a second official Zynthian kit with encoders and metal case and MIDI ports is worth every penny, but this may be an option to consider until you can justify a second kit if you decide to upgrade your kit to the RPI4.

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Thanks for your kind help! Eventhough i’m very at ease with all sorts of technologies (tube circuitry, basic electronic, optic fibre, V8 engines, woodworking, construction) I feel absolutely lost in the whole encoding and programming universe. This is why I opted for the V3 Kit, I don’t have the time for another skill really, working, being a family man, making music, drinking beer and wine…
When I see the exchanges between the programmers I feel like a big noodle, even if they’re really very very nice and cool.
So I guess I rather live with the audio clicking, it only happens every now and then.
Thanks again and enjoy your Sunday!

There is another option, @Vincent: You could ask for a “volunteer” that wants to “upgrade” your zynthian to RBPi4, and you could pay the costs and a good bottle of wine… Dionisos has great power !!

:blush:

I raise my glass to that!