If you look at he top section of page 2, in fine print it states “Contacts make on side actuator thrown.”
I hadn’t seen that. Now, to be honest, that still isn’t very clear to me! Oh wait… it is supposed to mean "Contacts are made on the side where the actuator is thrown to. Uh… OK, took a bit of deciphering, but I get it now
I wish I could show how good/bad the ripple is, but I don’t have an oscilloscope.
Anyway, thanks again for everyone who helped me out on this PSU project!
This was my first “real” electronics project, apart from passive speaker crossovers I built a couple of years ago. I am quite happy it all worked out. Now I can concentrate on putting it all into a nice box, and enjoying some music playing through the raspberry pi.
A couple of things I want to point out, and a couple of questions:
- I don’t really like these screw terminals. They were easy to solder on, but the plastic part is not solidly connected to the metal part, and thus it jiggles around.
- The Triad power supply is very quiet, actually, I have a hard time hearing it at all. Happy with that one.
- I am curious about what people here think about wiring (the power wires going from transformer board to regulator). Is it a myth or is it a fact that twisting the cables has some advantages?
- Small rubber washers, screws, and standoffs were supplied with the regulator board. Where should the washers go, between screw and board, or between standoff and board?
- The voltage regulator was supplied with a rectangular pad (thermal pad?). Instructions said to use a very thin layer of thermal paste on both sides of this pad. I used “Cooler Master” thermal paste, from a heat-sink upgrade I had for a video card. I suppose that is adequate?
These are just curiosity questions… so no urgent need for an answer. It would however be interesting to hear what you think…
[quote=“DrTebi, post:43, topic:8353”]
I am curious about what people here think about wiring (the power wires going from transformer board to regulator). Is it a myth or is it a fact that twisting the cables has some advantages?[/quote]
[quote=“DrTebi, post:43, topic:8353”]
I wish I could show how good/bad the ripple is, but I don’t have an oscilloscope.[/quote]
With an oscilloscope you could also see the ‘noise’ and what is left of that, after the input capacitors (and whatever else there is) on the amplifier board…
Relatively cheap and reliable ones are being talked about on eevblog forums - expect about US$ 300 for a decent 4 channel osci with a bandwidth of 100MHz. I got myself for home use a Rigol DS5054 (4ch, some logic analyzer capability) and a Owon SDS7102 with battery (2ch, floating mains measurements) - software wise the Rigol is more mature than the Owon.
Nowadays should be possible to get a 4 channel battery one for maybe US$ 500 with 100MHz.
But yeah, check out aforementioned forums, they discuss this stuff all the time and also do hacks of the gear to improve it - of some of the regulars approve of something and it’s been out for a while (to find bugs/problems), it’s pretty safe bet and you’d have a large community to help with problems.
Yeah, some are like that. Make sure the mains cable going into that box has a pull-inhibitor attached to the cable, so it can’t come out and you get to touch the bare powered wires.
And it might be a good idea to invest in some residual current miniature circuit breakers, if you build stuff like this more often (mostly only installed for wet-room sockets, they’re not much more expensive than simple MCBs, but will save your life if stuff goes wrong).
As for the wiggling - try to get some from a brand manufacturer or change the clamping system.
One I like is called cage-clamp. No idea if available for board mount and 230Vac though…
Depends on the type of washer, metal ones usually between screw and board, with rubber, I’d tend between standoff and board.
Avoid conductive TP (better heat transfer for CPU/GPU applications), use ceramic based types for electronics (usually white) and be aware that some can release the fluid over time (if you get them from ebay), which then goes wherever it wants.
Useful for differential signals. This ensures that most of the noise is introduced as common mode and can be separated from the signal if you have a high enough common mode suppression.
I think the best feature of twisting wires together is down to cable management and troubleshooting. Individual wires going every which way in an enclosure is an eyesore. Also, 3-years down the road when trying to figure out why it doesn’t work anymore, the pairs of wires will be obvious that they go together for some reason.
That’s a good point. There isn’t really much going on inside my chassis, but it is still nice to have the wires twisted and thus neat looking.
Attached a couple of pictures of what it looks like so far… I ended up using an old pre-amplifier case, I stripped the paint off and added a new back panel. Everything but the front and back panel will be painted dark gray (like the Sony “Pre-Esprit” series, e.g. the device below in the first picture).
I still need to machine the front panel, which is a bit tricky if you only have woodwoorking tools The front panel will have a power switch as well.