Updated: Mar 4, 2020
We are often asked, why we use terminals for input and output connections, instead of using a DC jack. We would like to summarize our reasons here:
Typical use case:
In nearly all use cases the HPULN power supplies are implemented in a chassis, the HPULN module is inside of an enclosure. With a HPULN power supply one shall reach the final power supply solution, so there's no need of a "faster" kind of a connector, than a terminal offers.
- Chassis space:
A terminal needs less PCB area, further no connector is needed, which usually would need around another 5 centimeters in front of the HPULN power supply. That can be a showstopper for many projects, which have only a little space left in a chassis. A cable is flexible, bend it how you need it - directly out of the terminal without wasting area.
A decision of the used cable can be a very subjective thing - use the cable you prefer, with more wire diameter than possible using a DC jack.
We use terminals with cage clamps only. That ensures the most surface contact between the wire and the terminal, resulting in a minimum of resistance. DC jacks have a small clamp, which in addition to the low contact pressure is the only contact to the round shape of the male DC jack - resulting in a small contact area only. That's why DC jacks are often rated with <60mOhm of contact resistance, which is by far more, then is reachable with a pure wire. Contamination (i.e. because of touching the (male) DC jack) can cause oxidation and so influence resistance once more.
Additionally we avoid one step of contact-transformation:
Terminal: PCB - terminal - wire
DC jack: PCB - DC jack - clamp - wire
- Power rating:
DC jacks are usually rated to 3, some to 5 ampere and low voltages only. Our terminals are rated to 300V / 13,5A.
We use high quality terminals, which are cheaper than usual DC jacks (male and female), though. We mirror that in our prices.
So is a DC jack generally a bad type of connection? No. But we see many advantages to use a terminal instead - especially for that kind of device, that is itself optimized and designed to bring your audio setup to the next level.