Posted on Saturday, 4th April 2009 by Jimmy Auw

I’m thinking of a digital volume control, instead of passive one (with potentiometer or stepped attenuator). Hmm… Searching around the net, I found some IC from Maxim. I grabbed some (with different packaging and functionality). Now I need to think how to create a new jig with this IC

Time to leave “analog” world? Well, I’m thinking about it…

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Tags: Attenuator, digital, IC, maxim, potentiometer, volume control
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Posted on Wednesday, 25th February 2009 by Jimmy Auw

Mercury: a heavy silvery toxic univalent and bivalent metallic element. That’s what I get from Google or common dictionary. Well, as long as it has good sound, it’s deserved to be auditioned.

Presenting, JAN/RCA NOS 83 Tube Rectifier. Thanks to my friend, Mr. A who allows a nice exchange of this nice tube with over a dozens of my Black Gate (that what’s friends are for)

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Tags: Audio, DIY-Audio, rectifier, tube
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Posted on Sunday, 15th February 2009 by Jimmy Auw

I’m thinking of… a full Black Gate Power Supply

Well, it’s not a dream since I have enough Black Gate F Series stock on hand. One value only, 680uF/65V. I need to use at least 10 pcs each (symmetrical power supply, remember? We are not talking tube, this is chip-amp project!). So total is at least 20 pcs. The troops are ready!

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Tags: Audio, Black Gate, Capacitor, chipamp, gainclone, power supply
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Posted on Saturday, 13th December 2008 by Jimmy Auw

A Gainclone challenge? Why not? Solid state? Why? Why? Why? Why? Why? Wise man says ask “Why” five times. But I think I will end up with same answer Sorry! Just consider this as a small killing time, boredom destroyer project uh…

But remember, we are on crisis, so no budget!!! So, I also don’t want to spend any budget… Well, small budget is ok, but really-really small.

Let’s straight to the point and back to the topic: I want to try a LM1875 Gainclone Amplifier. This is not my first time building a Gainclone, but first time with LM1875. Gainclone becomes famous because this “simple chip amplifier” could sound beautiful – in 47 Laboratory 4706 Gaincard (retail price near US$ 3000) and Jeff Rowland Concentra (retail price around US$ 6500). FYI, Gainclone family has some models, like LM1875, LM3875, LM3886, etc. Each has different specifications, especially for power rating and speaker load impedance – but all amplifier with this chip will be called as “Gainclone”.

I’ve received the PCB from my friend at local DIY forum. Now, it’s time to pick my “agents” – I mean my components

“As always, should you or any of your IM force be caught or killed,, the Secretary will disavow any knowledge of your actions. This tape will self-destruct in five seconds. Good luck, Jim.”

Well, just suddenly remember those classic Mission Impossible warning on every end of its mission tape. Now I’m starting to pick my agents. Let’s open my shelves and see what I can find. A Gainclone only need very small amount of components, around 10 pcs each channel. I think I still have some in my drawers.

Some capacitors on my drawer. Umm… I’ve collected these for quite long time.

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Tags: Amplifier, Audio, Capacitor, DIY-Audio, gainclone, resistor
Posted in Collectible Stuff, DIY Audio, Personal | Comments (76)

Posted on Thursday, 2nd October 2008 by Jimmy Auw

I manage to collect some old “not common” tubes as below

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Posted on Wednesday, 27th August 2008 by Jimmy Auw

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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Tags: Capacitor, film, headphone amplifier, unlytic
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Posted on Saturday, 26th July 2008 by Jimmy Auw

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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Posted on Wednesday, 23rd July 2008 by Jimmy Auw

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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Posted on Monday, 7th July 2008 by Jimmy Auw

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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Tags: Capacitor, DIY-Audio, power supply, resistor
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Posted on Sunday, 6th July 2008 by Jimmy Auw

My custom power transformers have just arrived. Like on my previous post, I plan to use 4 power transformer for my next Aikido project (two Heaters and two High Voltage). So here is the stuff

The first line above is the High Voltage power transformer (primary on 220V, secondary on 200V, 220V, 230V, 250V, 5V , and 7.5V). I have extra heater’s secondary in case I don’t want to use the additional transformer. The High Voltage itself rated at 200mA, while the 5V/7.5V rated at 3A.

The second line above is the Heater power transformer (primary on 220V, secondary at 5 and 7.5V). Rated at 3A. So, I completely separate the Heater and High Voltage power transformer, resulted in 4 power transformer for this project. (more…)

Tags: B+ supply, DIY-Audio, heater supply, transformer
Posted in Collectible Stuff, Indonesia, Personal | Comments (8)

Posted on Monday, 23rd June 2008 by Jimmy Auw

Well, this is a surprise news for me (at first). A “Made in America” PCB? Seriously?

Few months ago, my friend introduced me to TubeCAD (and finally led me to John Broskie). Actually, I knew his TubeCAD Journal and even his famous TubeCAD software 1-2 years ago (or more). But at that time, I didn’t have any interest on such technical things (like Broskie’s journals). Until finally, I heard his Aikido pre-amplifier and quite stunned how come a simple pre-amplifier (with cheap components) could lead into magical sound! Then I changed my mind and started to read some of Mr. Broskie’s journal.

My interest in some of his articles led me into a personal communications via e-mail (well, I do enjoy the modern technology, I wonder if I should send him an ordinary air mail to ask about his article – it will take years before I can get myself answered! With e-mail, within a night – due to different time zone, almost all of my questions could get the answers).

Finally, I decided to order his Aikido 9pin Mono PCB. John sent the package via express mail. It arrived around 2 days but due to custom issue, I accepted in around 5-6 days. Still quite a fast delivery

Here is the PCB. Dual sides, plated-through 2 oz copper traces. Don’t forget that both sides are silk-screened.

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Tags: 9pin, Aikido, DIY-Audio, PCB, Pre Amplifier, tube
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Posted on Friday, 18th January 2008 by Jimmy Auw

After a quite long searching period, finally I got my tube, the Brimar CV4024 and GE 12B4A. Actually, I was looking for RCA 12B4A or Tungsol. But got no luck for now But this two pairs of tubes should be good. Now I need to find a good pair of EL34 to start my EL34 SE project.

I have ordered custom DIY Output Transformer and some overrated Power Transformer (around 2A for both 12B4A, around 1.5A for both CV4024, and around 5A for EL34). We’ll see how this setup will perform   It takes some times before I can finish this project. So many things to do, but so little night to be spent. I wish I can have over 30 hours every day, not just 24.

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