Edit: Added some changes based on feedback, thanks everyone!
Hi there. Leaving this here in case anyone else is looking for this information. I was confused because there are a bunch of adapters that turn up on Amazon if you search for “quad cortex power adapter” and most of them aren’t what you want.
Anyways, you are looking for a 12V DC power adapter that can supply 3A. It is ok if it can supply more amps, and with these cheap adapters might be better to get one that’s way under it’s limit but up to you. Voltage has to be 12V DC, you can’t buy something with more V, it won’t auto select this for you.
The barrel end of your adapter should be 5.5x2.1mm but the inner diameter can safely go up to 2.5mm with the prong style (look inside and you see two contacts that are smaller than the inner diameter that grab the pin)
The barrel end MUST be negative polarity. Look at this chart
Again, I should have just looked at the supplied QC adapter as this logo is right on there.
Most adapters on Amazon are positive (negative on the outside,) so you can try to find one that has a negative center, or you can just get a little polarity reverser like this one
All in, this ran about $18USD which isn’t really that much cheaper than the OG QC adapters, but this gives you more options for how to power your QC. For example, the packaged adapter has a wall-wart style and this has a standard nema connector which will fit on a power strip. Or you could get a little DC voltage bar and build it into your pedal board or something.
Huh. When I was hunting around for USB-C cables to power the QC, I thought I’d read that it wanted 2.1mm. That’s what I ended up getting, seems to fit fine.
Watch out. I recently found a 12-24V 5a on the Wal-mart discount isle for $14 I bought for a spare for multiple peddles I own. I noted it another message about the $100 ones and got slammed. It actually had betters cords tha the QC one and perfectly quiet.
Thanks for this; I plan to order two sets so I can keep the included adapter at home, have one for my rehearsal space, and keep one in my gig bag. I appreciate it!
I noticed the link above goes to a polarity reverser rated for 3A. Since the power supply can source up to 5A, it could be a problem. Normally I would not pair those, but in this case, the QC should only draw 3A max and 2A in normal operation.
I looked for alternatives but did not see any. Many of the simple in-line polarity reversers I found have no published rating, or are rated lower (e.g., 2A). At least the one you linked has a rating. I would be curious to know if anyone found a 5A in-line polarity reverser.
Thanks for your reply; EE here as well. I totally agree. I mentioned in my previous post that the QC should not draw more than 2-3A max, so that scenario is not a concern.
The only risks would be if the QC malfunctions, or if someone later takes the 5A power supply (with the 3A polarity reverser) and uses it to power some other piece of gear. Those are unlikely scenarios, but if it is avoidable, I usually prefer to avoid mismatches. I was doing the FMEA in my head; I couldn’t help myself
to the electrical engineers in this thread. I’ve noticed the power supply I’m using here has a problem when trying to use with a mac and cortex control or as an audio interface. It works for a while and then stops responding, eventually it comes back without doing anything.
The provided power supply doesn’t do this.
Do you think this has anything to do with the floating ground in the provided supply vs the one I’ve linked? Other ideas if not?
Anything to do with power supplies with the QC and all the million posts about it, its suggested to stick with the original because other aftermarkets can cause more problems. Its a cheaply made one but causes less problems than the expensive cioks and other ones
