Posted on Thursday, 31st May 2012 by Auw Jimmy

Resistor is another interesting passive parts that could affect the sound. I used to be familiar with Vishay S102 Foil Resistor which well known as one of the finest sounding resistor. They are also very precise instrument grade resistor. Nowadays, some debatable opinion says that a naked version could sound even better. So I welcome you, a top-of-the-line naked Z-Foil resistor, TX-2575 made by Texas Components.

Interestingly enough, such company could receive one (single) pc custom value resistor.

Each rated around 0.6 Watts only. So I request several pcs combined to get higher rating. I don’t like s0mething less than 1 Watts (sound wise, they are not on the comfortable level), although the actual usage for this resistor on my application will be 0.04 Watts only.

This resistor is considered as one of the most expensive resistor if we calculate from the “cost-per-Watts” point of view. Available in 0.6 Watts rating only, if you want to get higher, then prepare to double or triple the cost.

(more…)

Tags: resistor, Texas Component, TX-2575, Vishay, Z-Foil
Posted in Collectible Stuff, DIY Audio | Comments (5)

Posted on Saturday, 26th May 2012 by Auw Jimmy

Perhaps you still remember the first article about designing the PCB? Now finally, the PCB has been done.

The result is quite awesome, as the specs also set at premium grade. This 2.5 mm thick red PCB has 2 oz Copper and TG170 grade. All solder pads are through-hole type, double layer with Immersion Gold finish. Tracks are on the bottom side. With this specs, I believe it will become a quite overkill solution for anyone who expects ultimate performance without compromise.

The idea actually comes from the situation where I find it’s quite difficult to solder a 9-pin Teflon socket directly. The spacing are too tight between those pins. So I feel very insecure when assembling my preamp. I’m always afraid some of my wires could touch each other then produce a short.

Beside that, usually we forget to solder the pins for longer time than it should (due to some reason like the wire is not joined well or one of the pin is shorted with other pin, etc). The heat (when becomes overheated) definitely will change some metal structure on the pin (not a good idea for the insulator also, although real Teflon is quite durable with such over temperature condition). Definitely heat is not a good friend for us (that’s why we know such Cryogenic treatment). With this PCB, the soldering becomes an easy job to be done (you will know how desperate to solder those wires to the tube socket’s pin rather than to the PCB’s hole). We can avoid the risk of overheating by using this PCB. And off course, esthetically wise, this kind of PCB looks gorgeous

It’s ok if you are using $10 socket which you can always replace them anytime without feeling guilty to your wife (ups!). But how about $70 Yamamoto or a ‘slightly’ cheaper, Luciano socket?

After looking around, I find a solution from Yamamoto which I like the tube socket very much. Yamamoto has extension PCB which will enlarge the spacing between the pins. But it seems the spacing is not enough for a ‘greedy’ guy like me. So forgive me Shigeki (Yamamoto), I have to make my own this time. But surely for the socket, Yamamoto is my reference idol.

So here we come with custom made PCB specifically for this purpose.

Below you can see the final result. Left side is the bottom view, while right side is the top view. Note the tracing is on the bottom side. Two extra holes on the side will allow us to screw this PCB to another PCB or chassis.

(more…)

Tags: 9pin, PCB, Teflon, Tube Socket, Yamamoto
Posted in Collectible Stuff, DIY Audio | Comments (10)

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.

(more…)

Tags: Alcohol, Choke, Double Boiler, Potting, Shellac, Wax
Posted in DIY Audio | Comments (12)

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…

(more…)

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

Posted on Friday, 11th May 2012 by Auw Jimmy

During my journey in this insane DIY Audio world, I tend to revert back my taste into kind a vintage. I also don’t understand why, but those vintage item give something special. One of the example is on one of my meter collection.

There are several brand of meter manufacturer, which has been in this industry for quite some time. One of my favorite is Triplett (I also like Simpson or Weston or GE, but their design is not as ‘elegant’ as Triplett, this could be my personal preference though).

As you can see below. This 300 DC Volts meter has a classic font. The black plastic combined with white background gives a sense of simplicity yet tough. The needle itself has a sharp rounded with hole pointer, which is also another special part that hardly to be found in newer design. The sharp part could be used to improve the reading accuracy (for minor number), while the hole could be used for the major number (50, 100, 150, etc).

To be honest, most modern meter only use a simple straight needle which definitely throw away the vintage passion (I believe one who uses analog meter must have some sentimental reason – so most of the time the design itself matter, not only the function).

(more…)

Tags: Triplett, vintage meter
Posted in Collectible Stuff | Comments (2)