Posted on Monday, 9th January 2012 by Auw Jimmy

I always have dream to have a separate and dedicated passive volume control. There was a time when I was offered to acquire few sets of Grayhill ‘M’ series rotary switch. Although it has 7 Decks which definitely overkill for most application, but seeing the quality of the switch, I decided to grab some.

Although ‘M’ Series from Grayhill is not Military qualified switch, but it meets the requirements of MIL-S-3786 which covers moisture resistance, medium and high shock, vibration, thermal shock (from minus 65 up to over 125 degree Celsius), salt spray, explosion, terminal strength (2 lbs pull minimum), and stop strength (15 pound-inches minimum). Quite convincing, huh? The simple but major different is, the ‘HS’ Military grade will have a sealed shaft and panel. That will make a lot of different in ‘heavy’ environment, but probably not much at home.

Each switch is bundled inside a plastic tube. Nice and convenient way to carry the switch and also easy to be put on the storage bin.

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Tags: Attenuator, Grayhill, Military, preamp, Switched, volume control
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Posted on Tuesday, 15th November 2011 by Auw Jimmy

So far, Auricap is one of my trusted capacitor brand – in power supply section. I still remember ‘few’ years back (when using this capacitor for the very first time) and comparing with Solen, Hovland, and Bennic XPP in my very first DIY speaker. Sounds familiar – if you were ever there.

Now, time has changed, but Auricap remains there. Affordable and sounds quite natural capacitor. I receive information from my colleague that Auricap releases latest type, the XO series. Not quite sure why Auricap uses XO as their new model. Probably as this new capacitor also available in very larger version (100 uF++, if I’m not mistaken).

Auricap is still my favorite in power supply section, after Solen. Well, so far if you are thinking a full film capacitor power supply, then Solen is a nice and realistic choice, as they are available in large capacitance, adequate 400-630 VDC, and definitely affordable price. Now, with the arrival of Auricap XO, which also offers large capacitance and high voltage, then the different is all about money (and performance to justify the cost).

I order 0.1 uF / 400 VDC and plan to use them in power supply section of my new Aikido Preamp.

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Tags: auricap, Auricap XO, Capacitor, preamp
Posted in Collectible Stuff, DIY Audio | Comments (2)

Posted on Sunday, 13th November 2011 by Auw Jimmy

During the upgrading process, the old Ceramic tube socket also got new replacement to the Teflon one. The problem is, the process to remove the old tube socket will not be an easy job, as removing other parts. Why? Because as other part usually only has 2 leads, the tube socket got 9 points to be removed.

Actually if you really want to re-use the old socket, you have to use hot air solder to remove the perfectly. But I don’t really have the need to re-use the old socket. So I cut them directly.

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Tags: Aikido, preamp, solder, Teflon, Tube Socket, WBT
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Posted on Monday, 7th November 2011 by Auw Jimmy

As I’m about to move my Aikido Preamp to a new ‘home’ (I mean, new chassis), then it’s time to fix all the components used there. Before, I have tested several components on different section and later then I got final conclusion to put what on where, etc. Below you can see one of the original parts used during my earlier testing stage. Now it’s time to finalize?

One most difficult thing is to unsolder all the components first. As you can see below, most of the parts are not yet fixed (long leads, hanging here hanging there, etc etc). Unsoldering them definitely would not be a nice evening job.

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Tags: Aikido, preamp, TX2575, Z201
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Posted on Wednesday, 12th October 2011 by Auw Jimmy

Still remember the first chapter here? I have transferred the paper mockup into digital format. It didn’t take long time to do that

Just need to send (or print) this format and send to the manufacturer. I’m quite sure they can make one for me.

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Tags: Aikido, power supply, preamp, Prototype
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Posted on Thursday, 6th October 2011 by Auw Jimmy

I did a stupid mistake. I ordered new chassis, but during the construction, I changed some parts and forgot if the new parts actually ‘lot’ bigger than the old one. Two most significant in terms of the size are Hashimoto C-25-150CH and Tamura A-4004. They both occupy over half of the space (see the right chamber, on the size of copper plate). The copper plate itself will hold a giant custom Z11 power transformer.

I have to think how to solve this puzzle… re-order a new chassis would be my last, worst, but also simplest option…

See how things going soon… What you see below is not a ‘complete team’. I still have a pair of VCap and a Jensen 4pole electrolytic to join.

Tags: Aikido, chassis, preamp
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Posted on Saturday, 23rd July 2011 by Auw Jimmy

This is the final choke upgrade that I’ve been waiting for quite long time. After some discussion on the phone with Brian (1 day before his birthday), finally I finalized the order. Custom made from Sowter UK, a Choke specified for Input position. Spec wise, it should be 30H with 75mA current capacity. Rated at 500V as this one will be placed in input position – so safety first!

FYI, most designer will not go with Choke Input approach. First, because the Capacitor rated at higher voltage is so cheap and widely available. It’s easy to get Capacitor rated at 630 VDC and the cost is so far very reasonable. Second, Choke at Input is a kind of “waste” in terms of voltage. It only produces DC around 0.9x from the AC voltage source, compared with Capacitor which could produce DC around 1.414x from the AC source. Kind of voltage waste? Sort of…

Back to the choke, DCR is optimized at Level 2 raised from the standard spec (well, if you know me so well, mostly I don’t go with standard spec). At Level 2, the DCR targeted around 260R from 300R at standard spec (but I got better on real measurement). I could have option up to around Level 4 which could reduce the DCR around 1/5 times lower, but it will lift the height of this choke to 6 Kg. I don’t mind to pay more for manufacturing process and material cost, but I do mind with the 6 Kg shipment cost and the tax!

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Tags: Aikido, Choke, Choke Input, preamp, Sowter
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Posted on Monday, 2nd August 2010 by Auw Jimmy

After completing the construction of my Duelund Interconnect 2.0 Rev2 here, I decided to do some short comparison. My friend has Duelund Interconnect 1.0 Rev1. I think this gonna be a nice comparison!

Direct to the stage, we have some equipment on hand, like floorstander 3-way speakers, CEC CD Player, Marantz CD4000 fully modified with tube output stage, Hybrid F4 power amplifier, Aikido 6N1P-6N6P powered with Duelund CAST Ag/RGN1054 Mesh Rectifier, and also #26 Pre-Amp powered with Jensen Paper Tube and AZ1 Mesh Rectifier.

Without any further ado, let’s go to review those cables.

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Tags: 26, Aikido, cables, Duelund, preamp
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Posted on Sunday, 18th July 2010 by Auw Jimmy

I this world, there are lot of tubes, with different filament supply. In most of my tube rectification application, I stand with two choice of rectifier, the one with 5 Volt filament (most Octal and UX type) and the others with 4 Volt filament (RGN or AZ families).

The best way to use two type of rectifier with different filament voltage is to use dedicated switch to select the exact filament voltage. You can also use Resistor to drop the filament voltage (up to 1V drop and 1A), but this way is not recommended due to a lot of heat must be dissipated (also not too good in terms of sound quality to).

I just finish the switch installation this afternoon. Now I can choose to use 4 Volt or 5 Volt filamen voltage. You can see the picture below.

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Tags: Aikido, preamp, RGN, tube rectifier
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Posted on Sunday, 16th May 2010 by Auw Jimmy

I plan to compare some capacitors from Jensen and one from Audio Note. The two from Jensen are Jensen Copper Foil Paper-in-Oil (Paper Tube) and Jensen Copper Foil Paper-in-Oil (Copper Tube). From Audio Note, I have Copper Foil Mylar-in-Oil (I believe this is Copper Tube also). We gonna have a serious battle later since those 3 caps are using different “recipe”. Both Jensen are Paper in Oil type, but with different enclosure. While the Audio Note has similarity with one of the Jensen with Copper Tube, but with Mylar instead of Paper. Audio Note claims the Mylar will provide better combination between sonic reproduction and the reliability.

Shall we prove the result? Later… We must wait after the burn-in session, probably in 100+ hours.

For the burn-in session, I sealed the Copper Tube caps with plastic. This is to prevent the oxidation of the copper tube (both Audio Note and Jensen Copper Tube oxides very fast in my environment due to high humidity, thanks to the purity of the material used also). I should prepare a transparent heatshrink for a good looking appearance, but no time to find one now. Perhaps you will ask why there are 2 pair of Jensen Paper Tube? One is my friend’s, to join the burn-in session before used on his system.

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Tags: Aikido, audio note, Capacitor, Duelund, jensen, preamp, tube
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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 Sunday, 28th March 2010 by Auw Jimmy

Few months ago, my Aikido transformer was burned due to my stupidity plugging in 100R bleeder resistor, instead of 100K one. Well, I have ordered another replacement few months ago, but just now I have time (and motivation) to install it. This one is an ultimate transformer I believe, with Z11 iron and Germany/Australia wire. I have big concern on power supply, since it’s the food for your audio system. So I expect good and healthy food, I mean, power supply for my audio equipment.

Due to different leads arrangement with my old transformer, I must do some extra job adding some extra wiring. Here is the result.

Not a bad 45 minutes of work, huh?

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Tags: Aikido, Duelund, preamp
Posted in DIY Audio | Comments (12)