Posted on Saturday, 24th April 2010 by Auw Jimmy

I just got my Oscilloscope, so I can play more fun with my DIY stuff. Ok, let’s start with some basic “game”, to find the inner and outer foil of a capacitor.

Basically, most of the capacitor, has what we call the inner foil and outer foil. Because, most of capacitor’s construction is based on the winding of paper or other conductor (silver, copper, gold, etc), so we will have a start position (the inner foil) and the finish position (the outer foil).

Although for the film type capacitor, it’s just fine to connect positive or negative to the inner or outer foil. But due to some reason, it’s preferable to connect the outer foil to negative side or to the “nearest” negative side (input side on coupling application).

Why? Because the outer foil will catch the outside interferences. So better if you can put this outer foil to the place nearest to ground or negative pole. So it could completely transfer those unwanted noise faster to the place where it should belong – the ground.

Some capacitor like Audio Note, Jensen, Auricap, Hovland, VCap, etc usually marks their capacitor with different color lead or print some black line to mark the negative side or input in the coupling application. Some other popular capacitor, like Mundorf, doesn’t seem to care about this, means no marks at all. So you got to check it by your own. Other capacitor like Duelund, which uses the Stacked Foil design, I believe doesn’t have any polarity (it’s not winded, but stacked).

How to do the test with Oscilloscope? Simple by testing both leads, and give some “interference” outside the capacitor (touch by hand or put some electric field interference e.g. high voltage cable, etc). The side with higher noise, means the outer foil.

Below are some picture from my own measurement on some capacitors.

Audio Note Oil Filled Mylar Capacitor. The black line marking on the capacitor’s body means the negative or input side. We can see the noise is quite big if we put the positive probe on the side which has black line marking.

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Tags: Capacitor, measurement, oscilloscope
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Posted on Sunday, 18th April 2010 by Auw Jimmy

The sign of a wear out tube? Time to grab some more… >.<

Tags: 26 tube, tube
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Posted on Wednesday, 14th April 2010 by Auw Jimmy

Straight to the point. Just backed home tonight from a crazy traffic, then it was a great moment to payback! Let’s solder the new Duelund CAST Resistor. You can see brief information about Duelund CAST Resistor here and  my DIY speaker here.

I decided to switch back to Auricap few months ago (from a set of Siemens NOS capacitors). I eventually realized that using too many capacitors in parallel may reduce some factor, like imaging and separation. The tonal should be similar, but some other factors mentioned before might be altered or reduced.

Okay then, let’s change the old Sfernice RLP10NI to Duelund CAST Resistor.

After around 15 minutes soldering, I completely finished the modification.

My first initial impression. The music was more solid, good depth and separation, but never got it too harsh. I also felt that it was even more relax in terms of musical pronounciation. If I felt that the Sfernice still has some “stiff” characteristic, then the CAST resistor absolutely very relax, even just powered on for few hours. To be honest, the role of this resistor is very important since the location is on the front of the signal path.

I will provide more experience after several hours. We sill have some Norah Jones, some Chen Lily, some Ingram Washington, some John Campbell, or also some Tsuyoshi Yamamoto.

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Tags: auricap, CAST, DIY Speaker, Duelund, resistor
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Posted on Wednesday, 14th April 2010 by Auw Jimmy

Finally, I change my main transformer orientation, from horizontal to vertical. Not really easy to mount this giant transformer vertically. But here is the result. I’m quite sure I love this new orientation than before

Actually, the best solution is if you can “sealed” the two side of the transformer by a metal plate (either aluminum or copper). But since my DIY chassis is completely “rubbish”, then I don’t think I can do that. Just prepare for a future plan, so I keep the vertical mount position now.

This Z11 based iron with Australia/Germany copper wire is rated around 150VA or more. With current load about 110VA from my preamp, this giant is completely cool for over 8 hours non-stop performance. Damned, I do love this transformer! Sadly, not easy to get similar transformer in the near future (Z11 is quite rare here and expensive).

Tags: transformer
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Posted on Sunday, 4th April 2010 by Auw Jimmy

Before, my main transformer was designed to be mounted in vertical position. As you can see, the L-Shape was designed to be bolted on the main chassis vertically.

Due to some reason, after few hours experimenting, I didn’t really like this vertical position. Why? I haven’t found enough evidence, but for now, I must change the mounting position, from vertical to horizontal.

After few hours on the local electronic parts shop, I managed to find some tools for this purpose. And another few hours to install this and here is the result. Tadaaa… My transformer is ready to be mounted horizontally.

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Tags: transformer
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Posted on Saturday, 3rd April 2010 by Auw Jimmy

Now it’s time to try the Duelund CAST Ag (CAST Silver) on my Aikido Preamp. You might be interested to read the installation process.

Short words, here is the final installation photo. For the break-in purpose, I don’t use expensive configuration. Usually the main source is my old iPod Photo, connected with old hi-fi amplifier, then my DIY speaker. Few hours break-in session should be enough for initial impression. Although serious listening evaluation must be done at least after 100 hours of break-in period.

Some brief information of my Aikido Preamp, if you are not yet familiar with it:

• DIY Main Transformer, Z11 core/38 size with Germany/Australia copper wire (330V-CT-330V/100mA, 0-4-5V /5A, 3.2V-CT-3.2V/5A, 0-90V/50mA)
• Russian 5U4, 5U4G-B, or RGN 1054 Rectifier (available via Octal->B4 DIY converter)
• Choke Input with 3 Chokes total, no Resistor in Power Supply line, except Bleeder Resistor (TKD)
• Jensen 4-pole, ASC, and VCap TFTF Capacitor in Power Supply
• 6N1P and 6N6P tubes
• Russian K40 as filament AC Bypass Capacitor
• DACT 100K Stepped Attenuator
• Jensen Copper Foil Aluminium Tube as High Voltage Bypass Capacitor (inside PCB)
• Kiwame, Riken, Shinkoh, and Vishay S102 Resistor in critical position and Vishay L6C on “not really important” position
• Duelund CAST Ag (CAST Silver) as coupling capacitor

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Tags: Aikido, CAST Ag, duuelund, preamp
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Posted on Friday, 2nd April 2010 by Auw Jimmy

My Sanwa PC510 multimeter has the capability to measure the temperature via small probe. So, I’m curious to measure my tube glass/surface temperature. I test the 6N1P, 6N6P, and 5U4G tubes.

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Tags: measurement, Sanwa, temperature, tube
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