Posted on Sunday, 24th June 2012 by Auw Jimmy

After around 12 hours and everything is cooled down, I manage to see the final result of my potting project. It seems like the pain has been well paid. The result is smooth as a delicious tofu. But after a very careful examination, I find a short crack. Not much, and definitely very tolerable.

Added: Duh, my mistake! I forgot to consider the top cover which has an elevated part a bit on the bottom side. So I think I need to melt the filler on the edge to compensate this…

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Tags: Choke, Lundahl, Potting
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Posted on Saturday, 23rd June 2012 by Auw Jimmy

If you haven’t read the first two post, then I would suggest to visit here and here first.

This is the 3rd experiment, and should be final one. I have done several experiments previously (although not published in detail here). So I have come up with final ingredients consisting of several natural materials.

So, let’s start cooking them!

Before I start, please be warned that this cooking way with open fire is not recommended at all! Use electric heater with controlled temperature or double boiler method. Most potting material (example: wax) has a flash point which could be ignited by the open fire. Although the flash point is quite high (few hundreds Celcius), but the temperature of open fire with gas stove itself could easily surpass those hundreds Celcius (hope you understand what I’m talking about). Never leave them unattended and never let them boiled even for a short time. Temperature would raise rapidly with such gas stove. Again, please do at your own risk!

All photos here were taken by my lovely wife As I have told you, I have to pay extra attention with this open fire technique.

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Tags: Choke, Lundahl, Potting
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Posted on Saturday, 19th May 2012 by Auw Jimmy

Please go back here if you haven’t read the first article. On this second part, I’m about to create the potting ingredients to pot my Lundahl choke. I have several experimental ingredients, so some of them might not be exposed in detail as the result is still beyond my imagination.

One of important thing that we have to remember is beware of the chemical and its effect. Some of this chemical could be dangerous if exposed with fire. The solution is to use temperature controlled electric stove or for a ‘poor man’s tools’ – I would prefer a simple double boiler. You can use candles (note the ‘s’, means you need more candles to reach your needed temperature) or you can use gas based stove. FYI, double boiler would be safer (if you can’t get a temperature controlled stove) as the temperature mostly would not exceed 100 degrees Celcius.

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Tags: Alcohol, Choke, Double Boiler, Potting, Shellac, Wax
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Posted on Monday, 14th May 2012 by Auw Jimmy

It’s been a while since this idea came to my head few months back. Now it’s time to make it happens. As you might also know that Lundahl is one of the good transformer maker. They use their own C-Core most of the time for their production, included this Choke.

Though I believe they don’t have issue with their “open” design, some people prefer to have it potted to minimize any vibration possibility (included me). So here I come, a potted choke project with this Lundahl.

First problem came to me few weeks back was how to find appropriate enclosure to house this choke. Definitely not easy. Doing custom made housing would be my last resort. After spending few weeks searching, I found a chassis from Hammond which was quite OK for my purpose. I tried to contact nearest Lundahl agent which located on Malaysia (Octave) but they didn’t have it. I also planned to give a visit to Martin Electronics located in Singapore as they carried quite a lot of Hammond stuff, but unfortunately, I was so busy in other thing and have no schedule to fly to Singapore. And last resort, I gave an email to Chris (Partconnexion) and his assistant as usual quoted me with best pricing. Well, I hated to spend almost the same with my goods price for shipping, but got no choice this time. Canadian post is always too expensive for me

After the Hammond came few days ago, it’s time to start drilling…

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Tags: Choke, Lundahl, Potting, transformer
Posted in DIY Audio | Comments (7)