Germanium Diodes and Socketing

[ItsGiusto]

Hello everyone! I'm working on a new build, and it includes the use of a germanium diode.

It seems to be common knowledge that when working with germanium transistors, one should socket in order to avoid heat damage. I was wondering if the same applies to germanium diodes as well. Should I always be socketing as opposed to soldering when working with any germanium semiconductor device?

On the subject, most builds I see that are not DIY do not socket at all, and instead just solder in transistors anyway, both silicon and germanium. Is there really actually much risk in doing this? If so, how do more experienced builders and companies do it all the time? Is this whole heat-damage thing just an urban legend, or is it worth listening to?
Thanks!
Justin

[greaser_au]

Basically these devices are created using heat to diffuse the doping into the substrate, and metal contacts are plated or bonded. If you overheat the device you can change characteristics  or even destroy the device.

The basic problem is that people new to soldering electronics (and even some with more experience) tend to solder like they are plumbing guttering (and I was no different when I started out nearly 40 years ago)... If you're working in a factory you either learn to solder very quickly and with the right amount of solder, or you're out doing something else...

the usual problems for new users are:
- not selecting the right place to put the iron
- applying too much (or too little) solder
- too long spent making the joint, usually due to dirty/oxidised components/wires/board/solder.
- using a too-powerful unregulated iron or winding a temperature-controlled iron temperature up too high because of a lack of understanding about selecting tip size.

If you cannot successfully complete a joint inside about 10 seconds, a clip-on heatsink while soldering will be helpful.

Note that it is not unusual to use sockets so that different devices can be 'auditioned'.

david.

[italianguy63]

I tend to use sockets to figure out which ones I want to use, but I still solder the final selection into the socket (so they won't rattle out, or later develop a "dirty" electrical connection).  Like Greaser said-- solder very fast.  If you can't, invest in some alligator clip heat sinks.

MC

[Arcane Analog]

I have "repaired" several "boutique" pedals where the builder made an otherwise great pedal but chose to socket their transistors. As mentioned, socketed transistors tend to develop connection issues or simply fall out of the socket.

Socketing is a poor build practice and a substitute for proper soldering technique. There is no reason to socket transistors or diodes unless the socketing facilitates quick and easy exchanges of parts for experimentation. A permanent build should not use sockets.

[greaser_au]

Socketing is a poor build practice and a substitute for proper soldering technique. There is no reason to socket transistors or diodes unless the socketing facilitates quick and easy exchanges of parts for experimentation. A permanent build should not use sockets.

There are a few reasons for using them (e.g programmable chips or high value devices), and *good*  sockets, properly sized for the application should be pretty much gas-tight at the contact point - once a device is seated that should be *it*. Machine pin sockets are VERY reliable, closely followed by double-wipe spring sockets - though single-wipe sockets should probably be banned as a crime against humanity.   This assumes the socket pins are not subject to excessive torque moment/vibration or devices will just walk out of ANY socket (valve retainers anyone?). 

How many cars are still on the road with the ECU memcals in single & double-wipe sockets - what's the magic for these?  a simple retainer clip.  If you MUST use a socket: use fine cable lacing - tie your DIPs and TOs down so they CANNOT move, learn to tie it off properly and varnish the knots!  Or just (quickly) solder those little buggas in once you're done playing (and if the trannies hang off to the side- tie them down anyway!).

In my years as a road tech, fixing pinball machines, video games, then later: computers, printers and network gear, at least half of my service calls came down to socketed devices - and a joggle/reseat got them going again (though I can't say I ever had to do this twice on the same piece of gear). I remember I sent a client a new (network) router which  didn't work and rattled when it arrived-  the 64-pin QFP flash chip (the config and code memory) had come out of it's socket - I've never seen that before or since!!

david

[chicago_mike]

2 second rule and you should be okay.  Use the right size tip and right size solder and you should be A-Okay. 

[ItsGiusto]

I tend to use sockets to figure out which ones I want to use, but I still solder the final selection into the socket (so they won't rattle out, or later develop a "dirty" electrical connection).  Like Greaser said-- solder very fast.  If you can't, invest in some alligator clip heat sinks.

MC

I do have a heat sink, but I don't really use it. I think for my own peace of mind, I'll have to use it when soldering these transistors and diodes in.

And I really like your idea of socketing, then soldering the devices into the sockets afterward. Sounds like a good way to be able to check that things work and make adjustments without having to desolder, but also make it permanent afterward. Thanks!
Justin

[ItsGiusto]

Hey everyone. I have another question. You all say that socketing isn't a good long term solution. Does this apply to ICs as well? I've always used 8 pin DIP sockets for things like opamps, and have never soldered them. Would it be prudent to go back and solder the ICs into the sockets, or is this case different from devices like transistors?

[amptramp]

I have a number of old transistor radios with germanium transistors and diodes that are soldered, so it can be done reliably enough for mass production.  Military design rules do not allow socketing of anything and if you think of a band travelling in all kinds of weather and tossing equipment into a van and bouncing around to the next gig, military rules for temperature, vibration and shock are not overkill.

[pinkjimiphoton]

I have "repaired" several "boutique" pedals where the builder made an otherwise great pedal but chose to socket their transistors. As mentioned, socketed transistors tend to develop connection issues or simply fall out of the socket.

Socketing is a poor build practice and a substitute for proper soldering technique. There is no reason to socket transistors or diodes unless the socketing facilitates quick and easy exchanges of parts for experimentation. A permanent build should not use sockets.

AMEN.
if ya HAVE to socket, solder the transistor leads to the socket itself. or expect it to wiggle out at the worst time.

old school analog hipped me to using a pair of needlenose to "crush" the plastic off sockets so they're easier to solder to component leads.
works well for those times ya need sockets.

but i too, have had so many failures of sockets i don't use 'em anymore. and if i DO, instead of using the SIP crap everyone seems to use, i get 6 pin ic DIP sockets, and cut 'em in half... the flea clips in them grip the component leads much better than the little round ones seem to do. once ya swap out a component 3-4 times, you can be pretty sure the socket connectionn is gonna end up failing down the road.

[amptramp]

We had a large multi-pin connector pair on the Hermes spacecraft where the number of pins was so large that it was rated for only three mate / demate cycles.  We used connector savers for all of our testing, which are connectors with a male and female end in the same body so you plug the spacecraft connector into the connector saver on both sides of the connection and mate and demate the savers rather than the flight hardware.  This keeps the connectors as pristine as possible.  But with the large connector with a 3-cycle life, we had to remove the connector and replace it for flight to maintain reliability.  We used this on everything from the tiny microdot connectors to the garden variety M3102/M3106 circular connectors to Cannon D-type connectors.

Moral of the story: NOBODY should trust connectors even if they are rated for spacecraft reliability.