Jimmy’s Junkyard

Well, I have one week holiday and I’m almost dead because of doing nothing. Since I have a pair of Aikido 9-pin Preamp PCB, why don’t I build one?

The main concern of this project is simplicity and cheap price. I don’t want to spend too much money for this project (just to kill my boring days).

So here is the PCB. Nice, sweet, well build by John Broskie.

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Nothing really important here, just want to publish my first book (scheduled on mid October 2008)… Before, I did some translation for some foreign books, but I decided to write my own. So this is the first one, and another will follow. I expect my second book will be better than this. More depth in terms of coverage and more general in terms of the potential readers.

A result of some sleepless night…

Well, I have been involved in a discussion in a local forum and surprisingly, many people don’t understand about grounding. It will take a long paper to discuss about grounding and you can find on Google. I just will write short article about how to test whether you have ground or not on your wall outlet.

Check picture below.

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Just take a shoot of my Aikido Preamp (6N1P, 6N6P, and 5U4C/5Z4 rectifier). Will upload the details later. Enjoy this cute pics. Beautiful, isn’t it?

Don’t ask me why I write this article. It’s just that… I like to learn new things… Everything. Just sometimes I get enough with my daily IT life, then why don’t I learn something new. Let’s say, a diamond

I have learned around, and got simple answer to pick a diamond: Color, Clarity, Cut, and Carat. It’s about 4C, no matter who come first - but I prefer Color and Clarity as first two, then followed by Cut and Carat.

Color
As easy as the word means, Color will define the color of a diamond. According to GIA (Gemological Institute of America), a name related with diamond certification, there are range from D to Z to define the color of a diamond. D means colorless diamond, while Z mean yellowish diamond. Colorless diamond means higher price (so a diamond with D color grade will be more expensive compared to a diamond with G color grade). Most diamond on the market (for jewelry or wedding ring) will have F or G grade (shouldn’t go beyond G if you want a colorless diamond). This grade should be expensive and colorless enough for common eyes. You will need a reference/master color set of diamond to do the comparison. Get the colorless diamond if you plan to combine diamond with silver/white gold, while you can go with lower color grade (yellowish) diamond if you plan to combine it with yellow gold. Another kind of diamond color is red or pink. This is very rare and expensive also. Here’s is some color classification (the color naming guide may vary a little bit, but most expensive “real” diamond will not go beyond G color grade):
- D-F: Colorless
- G-J: Near Colorless
- K-M: Faint Yellow
- N-R: Very Light Yellow
- S-X: Light Yellow
- Y-Z: Yellow

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Well, I need a big-capacitance high-quality capacitor to drive my headphone amplifier (we are talking 200-500uF capacitance and at least 400VDC working voltage). I don’t have too many choices (or perhaps no choice at all!). So I would go with this Unlytic Film Capacitor.

Yes I could go with Electrolytic capacitor but the sound would be not at my expected level.

So I welcome “The Giant” Unlytic capacitor Want to know how big is it? Keep reading.

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After Elna, BlackGate, and M-Lytic, now it’s time for the Obbligato. My order just arrived yesterday. I bought three types of Obbligato available on the market.

The picture above is the Obbligato Copper Case Aluminum Film Caps. The case is solid copper with soldered copper lead out wires and individually wrapped. The aluminum film is imported from Germany. All measure very close to rated value, max 5% but typically 1-2%. Wound tight, no voids gives a very transparent, smooth sound.

This capacitors looked beautiful with the solid copper case. Looked expensive, heavy, and well designed capacitors.

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Yesterday, another component arrived. This is one of the most important component for my B+ power supply. Welcome the Mundorf M-Lytic High Voltage “Special Custom Edition” 560uF/400V.

This special capacitor made by well known high end capacitor manufacturer, Mundorf from Germany, is probably one perfect candidate to replace the Black Gate era. Well, I just can’t afford the Black Gate WKZ, so this M-Lytic should be a perfect replacement. I might try the Unlytic also someday… If I can afford it

Enjoy the zoomed detailed version of the capacitor below.

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Usually, I never care about the theory behind all of my DIY project. Just plug it, hear it, like it, and finish it. But now, due to some reason (though somehow I also don’t know the exact reason why), I want to do it from scratch and want to be backed-up with some theory and calculation behind it.

My next project (again could be the last one) is a high end power supply for my Aikido pre-amplifier. I think I’ve mentioned about this project before.

This is the first part discussing about the theory behind my next DIY project (about the tube rectifier IFRM and capacitor/choke input). Next part will come soon.

Prologue:
I’m considering the usage of tube rectifier (I have Svetlana 5U3C or 5U4-GB on hand). So far, I only used to play with silicone rectifier where I don’t have to care about the size of filtering capacitor. Now, with tube rectifier, I have to learn the theory back again.

Tube rectifier, in this case my 5U3C or 5U4-GB, has only 1 Ampere of IFRM (Repetitive Peak Voltage Current) and 99 Ampere of IFSM (Peak Forward Surge Current). FYI, most silicone rectifier like IN4007 has both 99 Ampere of IFRM and IFSM. So any size of capacitor will be ok for this silicone rectifier (it won’t stress the rectifier, 99 Ampere is a huge number!).

The low capacity of IFRM of the tube rectifier makes the usage of big first capacitor is impossible. If you use big size of capacitor on the first stage after the rectifier, then this capacitor will stress the rectifier due to high load of current. Bigger capacitor will pull a lot of current. If this amount of current is bigger than the rectifier limitation (IFRM), then you probably could damage the rectifier. Please check the rectifier datasheet before you plug any big size capacitor (over 30uF) as your first filtering.

As you can see from the picture above (I use PSU Designer II from Duncan). With a too big first capacitor (errrr, 220uF is not that big, right?), you will put too much stress on the rectifier exceeding its IFRM. The big capacitor will need a big current to charge itself. If it exceeds your rectifier maximum IFRM value, then it may cause trouble. The result? I don’t think you want to know (or see) the effect

But I need a big capacitor to give smoother filtering… Then continue reading

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After here and here, well seems not enough, I have ordered some more components for my next DIY project. Just arrive today. The target is clear. This could be my last so should be my best DIY project. So, I’m gonna be serious… gotta be…

A bunch of Elna Silmic, around 16.000+ uF each channel for heater power supply? Are you serious, Jimmy?

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