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-   -   Board Terminals (http://www.diyaudio.com/forums/tubelab/179753-board-terminals.html)

Structo 24th December 2010 09:16 PM

Board Terminals
 
I notice that a lot of PCB amps here use the pcb screw terminal blocks.

Is this a better method of attaching wires to the board than simply soldering the wires to the board?
It would seem with the screw terminal that it would either work loose from vibration or oxidize after a while.

Are they used just because they are easy to work with?

I will be building the Simple SE after I get my board from Mr. Anderson so I'm doing some leg work before starting.

Thanks!
Tom

neonthecat 24th December 2010 09:30 PM

Tom,

Without trying to second-guess George here, I'd suggest he intended the Tubelab boards to be "experimental" for many users; hence the terminal blocks making for easy changes. If you simply want to solder wires directly, I can't see a problem with that.

BTW....Your avitar is an incredible likeness of yours truly around age 6. And that child is doing exactly what I did with a hairpin (and lived to remember the experience!)

tubelab.com 25th December 2010 01:54 AM

The screw terminals are used because many of the builders of the Tubelab SE complained about soldering the transformer wires directly to the PC board. In some installations the terminals make it easier if the board needs to be worked on or removed.

Usually the terminals require retightening once after the wires have been compressed for a day or two. The Simple SE that I built for shooting the pictures in the manual is still alive and well. If you prefer you can solder the wires directly to the PC board.

Quote:

Your avitar is an incredible likeness of yours truly around age 6. And that child is doing exactly what I did with a hairpin
In my case the paper clip met the wall outlet at age 5. Can't quite tell from the picture, but it looks like Dennis the Menace.

gootee 25th December 2010 01:55 AM

Are there cases where something is superior to soldering direcly? One such case might be grounds, e.g. under fault condition when shorted to AC Mains, where solder could melt or vaporize too quickly for breaker or fuse in service panel to blow, leaving AC Mains connected to user's body indefinitely. That is why the connection of chassis/ground to safety earth from service panel must be bolted (or welded), not soldered, for example.

There is also a lot to be said for not unsoldering and resoldering connections on PCBs. It's very easy to damage or destroy the PCB pads, by doing that.

But ease-of-use should not be taken too lightly, either. If you are "ever" going to remove and re-connect the connection(s), even just once, it is worth installing a removable connector, such as a Molex type or a Fast-On type or a terminal block (screw-operated or spring-loaded). But at least get a type that is very quick and easy to use. Screw terminals seem to be the most difficult to use of all of the removable types. Terminal blocks with holes for the wire ends and with internal clamps, either screw-down type or spring/finger-lever type, are easy to use and are fairly reliable. Fast-On (automotive "push on" blade type) are reasonably good, I think. And if you buy the exact right crimping tool, the Molex and similar types (and even just single pins and sockets) are good, as long as you get the tight-fitting version of the sockets and the correct matching pins.

P.S. Stay away from using gold-plated pins that solder onto a circuit board. And don't mate gold-plated connectors with tin-plated ones. Certain dis-similar metal pairs should not be mated. Gold and tin are just one example of a bad match.

Structo 25th December 2010 05:35 PM

Thanks guys!

Yes I get a few comments about my avatar.

Like many I was a toe headed blond with a inquisitive nature.
And although that picture is not me, it could very well be.

My younger brother however liked to chew on extension cords but I don't think
he ever made it all the way through the insulation. :D

Merry Christmas all! :xmastree:

DualTriode 25th December 2010 06:35 PM

Quote:

Originally Posted by gootee (Post 2409959)
Are there cases where something is superior to soldering direcly? One such case might be grounds, e.g. under fault condition when shorted to AC Mains, where solder could melt or vaporize too quickly for breaker or fuse in service panel to blow, leaving AC Mains connected to user's body indefinitely. That is why the connection of chassis/ground to safety earth from service panel must be bolted (or welded), not soldered, for example.

There is also a lot to be said for not unsoldering and resoldering connections on PCBs. It's very easy to damage or destroy the PCB pads, by doing that.

But ease-of-use should not be taken too lightly, either. If you are "ever" going to remove and re-connect the connection(s), even just once, it is worth installing a removable connector, such as a Molex type or a Fast-On type or a terminal block (screw-operated or spring-loaded). But at least get a type that is very quick and easy to use. Screw terminals seem to be the most difficult to use of all of the removable types. Terminal blocks with holes for the wire ends and with internal clamps, either screw-down type or spring/finger-lever type, are easy to use and are fairly reliable. Fast-On (automotive "push on" blade type) are reasonably good, I think. And if you buy the exact right crimping tool, the Molex and similar types (and even just single pins and sockets) are good, as long as you get the tight-fitting version of the sockets and the correct matching pins.

P.S. Stay away from using gold-plated pins that solder onto a circuit board. And don't mate gold-plated connectors with tin-plated ones. Certain dis-similar metal pairs should not be mated. Gold and tin are just one example of a bad match.

:snowman2: Hello,
Tell us more of the ill effects of soldering with tin solder to gold. I know the electrolysis story of dissimilar metals in piping systems. With pipe it takes more than dissimilar metals; it takes water, heat and an electrolyte low PH helps. Put it all together the moreelectro negative metal disappears then water & electrolyte run out grow mold and destroy things. What happens in the sparky world?
DT
All just for fun!


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