Germanium transistors, soldering iron heat and leakage...irreparable damage?

[Nocaster Cat]

So I've been working with a Tonebender Mk 1.5 build using OC75's with low leakages. I noticed that when I socketed them for Q1 position testing, I got very good results but after soldering them into place the output would drop significantly from where it was in the socketed/test circuit. When I tested the transistors again I noticed the leakages were definitely higher than they were prior to soldering. I know germanium transistors are sensitive to heat (and I do use a heat sink while soldering) but these OC75's seem to be hyper sensitive. My question is this...is the increase in leakage a temporary thing or have I "damaged" them and they're now permanently a higher leakage (I have not had time to go back and re-test them)? Thanks for the help!

[Nocaster Cat]

Bump.

[tonyharker]

The leakage in Germanium transistors is very temperature dependent and even changes in ambient temperature can affect it.
Excessive temperature will change the leakage permanently.

I dont know what sort of sink you used but each lead must have a heat sink clip on it - like this one - http://www.ebay.co.uk/itm/Clip-on-Solderers-Heat-Sink-/121522593263?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c4b4f9def - above the joint before soldering. 


Never cut the leads short, as the length of them helps to dissipate the heat of soldering.  Just cover them with sleeving.
If you want short leads use sockets.

Hopes this helps.

Tony

[Nocaster Cat]

Thanks Tony, that helped a lot.

[R.G.]

Heat damage to germaniums from soldering is irreparable. If they're leakier when they are cold again, they're leakier permanently.

Sorry.

The shorter a germanium device's lead is, the quicker and more expertly it must be soldered.  A heat sink clipped onto the lead dramatically slows down the rate at which heat gets past that point into the device.

[Nocaster Cat]

Any recommendations for a small heat sink? I saw Tony's link but that's for eBay UK.

[davent]

Alligator clips, small clamping forceps you may already have.