Posted on Wednesday, 14th October 2009 by Auw Jimmy

I have made RGN/B4/B5 to Octal Converter few weeks ago. Actually, the converter was made for 1A RGN Rectifier (because of the resistor drop value). I put 2 x 0.5 Ohm to drop 1V from 5V to 4V. With 1V voltage drop and around 1A current, I expect around 1W power dissipation. So this 6.5W Dale resistor should be fine (although a little bit warm after several hours of usage).

Later, I decided to make a new converter for 2A RGN Rectifier. Assuming 2A current and 1V voltage drop, the 5W or 6.5W Dale resistor should be fine, right? Wrong!!! My 5W Dale resistor got overheated (completely untouchable by hand) around 30 minutes of operational time.

Was I losing my math? I didn’t know.

So, I made another converter consisting two resistor in parallel. So the total power dissipation should be around 13W (2 x 6.5W). We’ll see whether those will get overheated again or not

Tags: Dale, RGN Rectifier
Posted in DIY Audio | Comments (2)

Posted on Sunday, 11th October 2009 by Auw Jimmy

Still remember my other “stupidity” here? After several hours of investigation, I finally decide that the Jensen Copper Foil Paper Tube is not a good capacitor for bypassing purpose. The music will lose most of its detail. YMMV, this is based on my investigation. Feel free if you have other opinion.

On the other side, I still have the “Classic” Jensen Copper Foil Aluminium Tube. Surprisingly, this capacitor works better on the High Voltage bypass section! The price of this capacitor is only 1/3 of the Paper Tube. I will give some more listening test, but so far I would stick with this “Classic” Jensen on the bypass section. This “Classic” capacitor gives warmth sensation without losing the details.

Tags: Bypass Capacitor, Capacitor, jensen, power supply
Posted in DIY Audio | Comments (8)

Posted on Tuesday, 6th October 2009 by Auw Jimmy

I do love the improvement after I finish the VCap TFTF Capacitor Mods on my Aikido Power Supply. The staging is awesome. I could “see” not only a center point, but also a little bit left/right, even more left/right, left/right (on the speaker), and far away left/right. But sometime, I feel the Pre-Amp is too dynamic (to speedy). For instrument music, it’s ok. But for mostly vocal dominated music, I think I need to slow it down – a little bit – without losing the awesome staging off course.

Since we know the “problem” is caused by the VCap TFTF, so we have to start the solution from this point also (it’s just because I have “predicted” that I have no option to improve on the other section).

Ok, what should we do?

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Tags: jensen, power supply, VCap
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Posted on Sunday, 4th October 2009 by Auw Jimmy

To simplify the answer, Bleeder Resistor is used to “short” the positive and negative rail on your High Voltage (B+) circuit. The main reason is safety. Without Bleeder Resistor, your capacitors will store some amount of electricity after your system turned off. This may result of hazardous shock if touched, accidentally off course

This time, I change the old Bleeder Resistor (no brand metal film) into Kiwame Carbon Film Resistor with 5W rating. Here you go.

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Tags: bleeder, Kiwame, resistor
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Posted on Sunday, 27th September 2009 by Auw Jimmy

It’s over midnight. After my previous mod on my Aikido Power Supply section here, it’s time to test it with RGN rectifier. I pick my Tefefunken RGN1054 Mesh Rectifier (before, I use Russian 5U4C, not a bad rectifier though).

The result? RGN offers even more transparency, even more detail, and the most important is, it gives the “musicality” there. I would translate the “musicality” here as the sweet harmonics delivered on every tone played.

But, it lacks the low register a little bit though… In a really small margin, but you could hear that the bass is not as punchy as before (with 5U4C Rectifier). I will try later with Telefunken RGN 2004 Mesh Rectifier, since I need to modify my converter socket first.

That’s all for now. It’s sleeping time!

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Tags: rectifier, RGN
Posted in DIY Audio | Comments (4)

Posted on Saturday, 26th September 2009 by Auw Jimmy

It’s a weekend holiday and it’s time to scratch my laziness and doing some audio DIY mods. This time, I will try a capacitor from Jensen, the 4-Pole Electrolytic.

What makes it different from standard electrolytic? Well, it has 4 poles instead of 2 of standard electrolytic (that’s why they call it Jensen 4-Pole capacitor – I wonder why 4-Pole instead of 4-Poles?) But that’s simply out of our discussion here.

Again another question, why it has 4 Poles instead of 2? Keep reading.

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Tags: Aikido, Choke, jensen, power supply
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Posted on Wednesday, 23rd September 2009 by Auw Jimmy

I dig my parts bin and found some resistor values which I needed to upgrade my Aikido. I used three brands here, Riken RMG “Metal Film”, Shinkoh “Tantalum”, and Kiwame “Carbon Film”.

Lets fire up the soldering iron

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Tags: Aikido, DACT, resistor
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Posted on Wednesday, 23rd September 2009 by Auw Jimmy

If before I picked Obbligato as last Power Supply (High Voltage) bypass capacitor, now I’m experimenting with Jensen Pure Copper Foil Paper Tube in this position.

The result? Well, not as significant as VCap on the first capacitor (after first Choke), but compared to Obbligato, I feel “oh so natural” sound with this Jensen. Now the Jensen is side by side with the Duelund

Tags: Duelund, jensen, power supply
Posted in DIY Audio | Comments (1)

Posted on Sunday, 6th September 2009 by Auw Jimmy

Yes, you might call me crazy! A Teflon VCap TFTF on Power Supply section?

If I need to make myself clear, this 0.47uF/600VDC VCap TFTF Teflon capacitor will cost you around US$ 150 each (depends on quantity). So we will spend near US$ 300 only for two VCap TFTF here!!!

And eventually, you will ask why do I put those caps there? Actually this is an “accident”. I bought those VCap few months ago, but it just didn’t match right with my current system (it prefers Duelund CAST PIO) – check the article here, here, and here. So what should I do with them?

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Tags: Aikido, power supply, preamp, VCap
Posted in DIY Audio | Comments (13)

Posted on Sunday, 30th August 2009 by Auw Jimmy

Still curious about the different between Jensen Copper Foil Paper Tube and Duelund CAST PIO, I held another session to benchmark both capacitors. You can read previous articles here and here.

This time I visit another friend. His systems as shown below. Briefly speaking, we can see a Fostex full range speaker with extra Visaton Super Tweeter. The source are Cayin CDT-17A (fully modified on its analog stage and additional reclock module) and a turntable (VPI Scout with Super Platter and Van den Hul Grasshopper IV GLA cartridge). The preamp is Tube #26 with RGN Rectifier. The power amplifier is RS241-12E1-6J5 with RGN Rectifier also.

We compare the Jensen Copper Foil Paper Tube and Duelund CAST PIO on the position between 12E1 and RS241.

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Tags: Duelund, jensen
Posted in CD/DVD Review, DIY Audio | Comments (18)

Posted on Sunday, 23rd August 2009 by Auw Jimmy

Never ending tweaks and mods? Yes I think so. Actually, my Aikido Pre-Amp already sounds good. But as a DIY, I think the journey never ends. Tomorrow always comes with another mods. After completing the PSU mods with Mundorf MCap Supreme 3.3 uF/800VDC and ASC X386S 40 uF/440 VAC here, I decide to go further with some other components.

First, I still hear small hum. This is mainly caused by the Filament/Heater Center Tap of my DIY transformer is not exactly on the center. So the 1/4 B+ isn’t injected on the correct Center Tap position. The only solution is to create a Virtual Center Tap with a pair of 100 Ohm resistor. I use 100 Ohm 5W Kiwame. Some people may say that you can use any cheap resistor for this purpose, but I always choose the best price/performance. At US$ 2 each, Kiwame fits this job perfectly. Make sure you use an accurate resistor (metal film should fit best, carbon film also ok).

I fire up my Aikido and ta-da… no more hum, even when my ear next to the speaker! But I need to confirm later with high-gain amplifier. With a normal/standard gain amplifier, the hum is usually less noticeable.

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Tags: Aikido, DIY Audio, Duelund, Kiwame, mundorf, preamp
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Posted on Tuesday, 18th August 2009 by Auw Jimmy

After you read this, perhaps you would expect a better system to test the capacitors. So today, I visit a friend, and test the capacitors on his system. We can call him, Mr. X. Here is some brief of Mr. X audio system.

Below is the power amplifier. Powered with RS241, RE604,and 6J5. Rectifier is RGN 2504 (later we try Klangfilm RGN 4004). OT is Tango. Currently powered with Jensen Copper Foil Capacitor and old NOS Western Electric capacitors. FYI, RS241 is claimed by most audiophiles as best sounding tube amplifier (forget 300B or 2A3) – and it’s really proven, if you have chance to hear it. This is an ultimate Single Ended tube amplifier (if you really know what do RS241, RE604, and 6J5 really mean to an audiophile).

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Tags: Capacitor, Duelund, jensen, mundorf, tube
Posted in DIY Audio, Indonesia | Comments (38)