Jimmy’s Junkyard

Passive Preamp with DACT Stepped Attenuator

Posted on Sunday, 21st June 2009 by Auw Jimmy

I plan to separate my system volume control with dedicated passive preamp. Before, I planned to take one attenuator from Goldpoint but due to some reason, I changed my mind and took one from DACT.

A stepped attenuator has advantage over typical potentiometer, especially for sound quality and attenuation precision. But do mind that most attenuator is expensive.

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Tags: DACT, Kimber Kable, Stepped Attenuator, WBT
Posted in Collectible Stuff | Comments (0)

TentLabs XO2 @ 27 MHz

Posted on Sunday, 14th June 2009 by Auw Jimmy

I need some touch for my old Toshiba SD-2960 DVD Player. So here is the TentLabs XO2 @ 27 MHz, a perfect yet affordable reclock solution for my wallet.

This is actually a simple PCB. Not all parts used, since this PCB actually “upgradeable”. I bought the XO2 version (Clock Upgrade + Low Noise PSU). If in the future, I wish to upgrade to XO3 (XO2 + S/PDIF reclock), I just contact Guido Tent @ TentLabs to put more components on this PCB.

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Tags: DVD, PSU, Reclock, TentLabs, XO2
Posted in Collectible Stuff, DIY Audio | Comments (2)

Be Prepared for Extreme Capacitors Battle

Posted on Saturday, 13th June 2009 by Auw Jimmy

Most of the time, money could buy anything – except time (and sometime, love ). Like this Duelund CAST-PIO capacitor. You have the money, but you have to wait around 6-8 weeks (not including shipping time), before you could get it on your hand (even if you could pay more, it won’t arrive faster). Well, it happens on me. After a long time waiting for this, finally it arrives today – the current most praised and perhaps most expensive capacitor (I’m not saying it’s the best sound one – not yet), Duelund CAST-PIO Copper (Cu) capacitor. I bought the copper foil version. The most expensive (and not reasonable from my point of view) is the silver foil, but that one should be completely out of my imagination (and budget).

Handmade in Denmark? Some say you can’t rush the Danes and yes you can’t. Just wait 6-8 weeks before they will finish your order. This Duelund VSFCu-PIO/CAST is rated at 630VDC or 300VAC.

Suffix CAST means this is the highest grade compared to VSF version only (without CAST). According to Duelund, as below:

The Duelund CAST Capacitor is our no holds barred flagship capacitor.

The construction builds on the foundation of our Virtual Stack Foil design but does so with the addition of a proprietary WPIO dielectricum which necessitates several days of impregnation under high pressure.

Hope they are right, otherwise I shall regret for the rest of my life for buying this capacitors

I plan to run some benchmarking from these capacitors below, to get the “King of Capacitor” title of my version. Please be noted that the best for my ears doesn’t have to be the best for your ears to. YMMV!

The contenders:

Duelund VSFCu-PIO/CAST - 1uF/630VDC/300VAC
Mundorf Silver/Gold/Oil – 1uF/1200VDC/800VAC
Jensen Copper Foil Paper Tube - 0.47uF/630VDC
VCap TFTF – 0.47uF/600VDC
Jensen Copper Foil - 0.47uF/630VDC

I remove Audio Note Capacitor from my list, since I hate its leakage issue. Good capacitor but less durable is simply out of the league (well, at least for me). I hear the new Oil Filled Mylar from Audio Note is better and safer. Will try if I have chance later.

It’s also interesting to see the battle between Jensen Copper Foil (old one) vs Jensen Copper Foil Paper Tube (latest generation). Just like Audio Note with its new Mylar Filled Oil, Jensen also update their premium capacitor line-up with its Paper Tube version. This Jensen Paper Tube version priced around 2.5 times more expensive compared to the standard Copper Foil.

Now, it’s break-in time!!!

Tags: Capacitor, Duelund, jensen, mundorf, v-cap
Posted in Collectible Stuff, DIY Audio | Comments (11)

Basic Amplifier Mods for Dummies

Posted on Sunday, 10th May 2009 by Auw Jimmy

I have received so many emails asking about how to do the mods. Why I do this? Why I do that? Etc… Ok, I will spend my lazy evening to use one good example and write a simple tutorial here. Just enjoy.

I look around my room to find a good and easy example to support this tutorial. Then, my eyes stunned to my old Simbadda CST z120 Dual-O speaker set. Well, it a small speaker, you can’t call it audiophile or even near it. I open the case and find that this small “thing” could become our perfect object.

You can get at your near computer retailer for very cheap price, less than US$10, I think. Feel free to find any other object. I pick this one simply because this is the only thing that I can find at my room (and suitable for this experiment).

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Tags: Capacitor, mod, pc audio, Simbadda, speaker
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More… Asus Xonar U1 Mods

Posted on Sunday, 10th May 2009 by Auw Jimmy

After around 20 hours testing of my previous Asus Xonar U1 Mods, I think I need to add some more mods here.

I have some plans here:

Old Blu-Tack tricks
PSU capacitors bypassing

Since 20 hours is not enough to listen complete characters of my previous mod, so we can eliminate the 2nd option. Let’s go with the first option, the Blu-Tack tricks. I’ve done this Blu-Tack mod before, please check it.

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Tags: Asus, Capacitor, mod, pc audio, usb, xonar u1
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Asus Xonar U1 Midnight Mods Session

Posted on Friday, 8th May 2009 by Auw Jimmy

Yesterday, it was at 00:00 am at the morning and I just couldn’t close my eyes. I’ve planned to mod my Asus Xonar U1, but never thought I would do it yesterday, in the middle of the night

Asus Xonar U1 is a “cheap” USB sound card, powered by C-Media Nitrogen D2 audio processor. The photo as below Cute with red/blue blinking lighting.

I want to put a warning first. Actually, modding such card will not bring outrageous result. So consider this mod is only for fun, huh… If you have extra capacitors on your shelf, extra time, and extra skill to de-solder those small capacitors inside. Let’s begin!

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Tags: Asus, Capacitor, mod, pc audio, usb, xonar u1
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Nippon Chemi-con RWE 820uF/550VDC

Posted on Friday, 1st May 2009 by Auw Jimmy

I digged my old boxes and found this old vintage capacitor, Nippon Chemicon RWE 820uF/550VDC. Very big in size (a little bit bigger than my ASC 40uF/440VAC and surely a giant compared to AA battery). This electrolytic capacitor is a legend one, made for inverter application. Equipped with screw type terminal, this capacitor is really ready to rumble.

Tags: ASC, Audio, Capacitor, DIY-Audio, nippon chemicon
Posted in Collectible Stuff | Comments (5)

Beautiful Glowing Tubes This Week

Posted on Sunday, 19th April 2009 by Auw Jimmy

I dig my tube boxes and found this old tube. Not a really expensive or most wanted tube, yeah… just an old Western Electric 393A tube. It’s a Argon and Mercury Vapor filled Thyratron tube. According to the datasheet, the addition of Argon gas on the Mercury Vapor atmosphere allows the tube to start conducting at low temperature. Ok, forget those technical literature, just watch the tube in action.

I heat up the tube for a while. According to the manual, to maintain the life span, it’s recommended to heat it up first. I give around 3-4 minutes. You can see the filament is glowing inside the metal bracket on the center of the tube.

Time for action, activate the High Voltage… Voila, the sky of blue on the top of the tube. Very beautiful!!! You still can see the red filament glowing inside the blue Mercury atmosphere.

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Tags: glowing, Mercury, tube, tube tester
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“Perfectionist” Design

Posted on Sunday, 19th April 2009 by Auw Jimmy

Being a perfectionist is not easy (and not cheap). Still remember my ambitious project before? I want to make it perfect, so let’s start the 1st phase, testing the capacitor (I mean, the Black Gate)

I will use 60 Black Gate capacitors on the power supply. First 30 pcs for positive rail, and another 30 pcs for negative rail. I want both rails have similar capacitance (or as similar as possible). So first capacitor on positive rail will have similar capacitance value on first capacitor on negative rail. Too perfectionist?

I need to know exactly the capacitance of each Black Gate. You know that every capacitor has around 10% tolerance. So when it’s written 680uF, it may vary between 680-68 or 680+68. Who knows? The meter knows.

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Tags: Black Gate, power supply
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Single Ended Amplifier Weekend Benchmarking Session

Posted on Sunday, 19th April 2009 by Auw Jimmy

It’s time for Single Ended amplifier benchmarking session. Located at Bakmi Margonda, Sarinah, Indonesia.

Here is some shoot from the event. The system was very simple, Tannoy speaker, Audio Aero Capitole CDP, and AirTight 300B as Reference Amplifier.

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Tags: Amplifier, Blind Test, single ended, tube
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Beautiful Glowing Tubes

Posted on Sunday, 12th April 2009 by Auw Jimmy

One factor that makes me like tube is its glow. Well, it’s hard to explain, but some tubes have a beautiful color, especially in dark room. Here is some of them.

Below is the 0A3/VR75 tube. It has red/fire color. Very bright and aggresive.