Posted on Tuesday, 30th August 2011 by Auw Jimmy

One of must have software when simulating power supply is PSU Designer II or PSUD II. This amazing freeware could simulate your power supply behavior, before you start to assembly your circuit. Off course, not all looked good means good for ears, but at least we can try

Below is my current Aikido PreAmp power supply circuit. The rectifier actually should be RGN, but I can’t find it on the list. So let’s roll with similar one, the common 5U4-GB.

The chokes are various from Sowter, Electra-Print, and Lundahl. Plan to take another amorphous one from Tamura, but we’ll see. Capacitor also varies, with V-Cap, Jensen, ASC, and the last minute acquisition, Black Gate WKz.

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Tags: power supply, PSUD, tube
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Posted on Tuesday, 30th August 2011 by Auw Jimmy

I have been a fan for Black Gate for quite long time. My first time impression probably nearly 10 years ago. I forgot whether I heard SKz or WKz at that moment, but I did remember the beauty of tube amplifier, smoothed by those Black Gate (probably not just Black Gate who contributed for the amazing sonic at that moment).

But 10 years back, I didn’t dare to play hundred of Volts for designing tube based equipment, then high voltage Black Gate such as SKz or WKz was out of my consideration. I got some and sell some… Mostly, I preferred to play with NX series, which very common in low voltage application (as low as 6.3 Volts). Very useful in D/A application. Some people say the Black Gate NX (especially the HQ – High Quality version) is very good in D/A coupling application. It produces very neutral sound, transparent, almost nothing (like direct coupling). But some people don’t like this kind of ‘sterile’ sound. Not analog, some people complaint.

Actually, other best application for Black Gate NX series is on the power supply smoothing section, especially on the D/A side.

I still own several N/NX/Hi-Q series, FK series, F series, PK series, Standard series, C series, and off course, the latest acquisition, SKz/WKz series.

All the latest WKz series (not WK, SK or SKz) will have a green ‘Goddess playing harps’ and  ‘Heart of Muse’ text. Actually, Black Gate is not the only one who uses ‘Muse’ in their capacitor series. We also can find Nichicon who uses ‘Muse’ in their line up. Term ‘Muse’ itself (one of them) could refer to any of 9 daughter of Mnemosyne and Zeus. Still on the same mythology, each of the Goddess possesses specific art or science. Probably this one loves music…

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Tags: Black Gate, Capacitor, SK, SKz, WKz
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Posted on Tuesday, 16th August 2011 by Auw Jimmy

Some people send me an email asking about how to measure cathode current and resistor rating. I will show you how to do it and actually this way is not only applicable for cathode resistor (but commonly used for that purpose).

Basically, there is 2 common way to do it. First, put you Ampere meter in series with the resistor. Second, is to measure the voltage on the resistor, then calculate the current based on the Voltage, Current, and Resistance formula (which V=I*R).

For the sake of simplicity, we can opt to use the second method. We cut the shrink from the resistor pins and put the probes there.

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Tags: bias, cathode resistor, Sanwa
Posted in DIY Audio, Measurement | Comments (0)

Posted on Tuesday, 16th August 2011 by Auw Jimmy

Sometime I’m curious how hot your tube is? Well, this short experiment will give you some idea. Different tube may have different thermal characteristic (simple logic: the higher current on the filament, expect higher temperature).

Off course we can use probe to measure the surface temperature. But I’m thinking another approach. So I get myself an infrared thermometer to examine the temperature in more detail. As example, I use Russia 5U4 Rectifier tube, rated at around 2A filament.

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Tags: 5U4, infrared thermometer, rectifier, tube temperature
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Posted on Friday, 29th July 2011 by Auw Jimmy

Last upgrade, the switches. Basically, in most tube application, we will use two switches. The first is the main switch which will control the main AC voltage to supply the main transformer. The second one is the one which commonly called as stand-by switch. This will control the High Voltage (either cut in AC – before rectification or DC – after rectification) supply to power up the tube.

The first switch is quite easy to get, as this is common voltage (either 110 VAC or 220 VAC). But the second one is not too easy, since we will deal with voltage more than 220 VAC (usually 300-500 VAC/VDC). Most people will use standard 220 VAC rated switch, which is actually quite safe, since this second switch only run <200 mA current (most 220 VAC switch is rated 5 A or more).

But as this is the ultimate project, of course we will not use such shortcut approach. After some searching around, my choice hits to the Leviton 30A – 600 VAC rated switch. This double poles switch has silver-alloy contacts and designed for fast-make/slow-break. This is really what I’m looking for from a High Voltage switch. With 600 VAC rating, I think I can sleep very well when use this one on 350 VAC secondary.

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Tags: High Voltage, Hubbell, Leviton, Stand-by switch, tube
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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 Saturday, 23rd July 2011 by Auw Jimmy

A special edition of MJ Audio Technology Magazine from Japan. A must have for 300B/2A3 lover! Quite expensive, especially if you buy it outside Japan.

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Tags: 2A3, 300B, book, Tube Amplifier
Posted in Collectible Stuff | Comments (0)

Posted on Sunday, 17th July 2011 by Auw Jimmy

After a long journey listening hundreds of tracks, finally I come up with JimmyAuw.com Reference CD #1. This CD, off course due to law regulation, are made by me and only for my own private collection. I use it to simplify myself when testing some audio system. So I can save my space on the bag to bring other things, instead of bringing several CDs.

Actually, it was very hard to pick only few tracks from hundreds of my collections. I think I will come up with Reference CD #2, #3, and so-on. For this Reference CD #1, I think mostly I put vocal tracks there. Probably female is more than male one. Well, that’s probably my own personal taste. Most single ended tube will love the tracks on it.

The JimmyAuw.com Reference CD #1 was recorded on Apogee Reference Gold CD-R. Carefully burned on “protected” machine in order to achieve best result. Probably not the best on the planet, but surely the best than I can get after experimenting with a lot of configurations.

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Tags: Audio System Testing, Reference CD
Posted in CD/DVD Review, Collectible Stuff | Comments (11)

Posted on Friday, 15th July 2011 by Auw Jimmy

To tweak a lot of things, usually I reserve a good set of tweaking tools. One of them is the tape. The function, mostly, is to seal something (wire/chassis/transformer) in order to prevent unwanted outsider interference to come in.

During my experience, I always stock four types of tape. My first one is Copper tape (quite common, for cheaper one, you can have aluminum tape).

Second is Teflon tape which well known of its durability to withstand of very high temperature, quite common in industrial machinery application and also in audio (probably you’ve ever heard one of the most expensive Teflon capacitor, V-Cap).

Third is Kapton tape. This tape also can withstand a very high temperature, but probably not a common stuff to be used in audio.

And the last one, also a unique one, is a silk tape. Don’t ask me how to get the last one, as you might think I’m “quite” insane (indeed).

Different type of tape will be used on different location and different purpose. Sometime, more than one type used on the same time. Feel free to try yourself, as I might not share those experiments at current time

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Tags: Copper Tape, Kapton Tape, Silk Tape, Teflon Tape
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Posted on Friday, 15th July 2011 by Auw Jimmy

Not yet finished chassis. Quite huge for a preamp, around 42×42 cm in size. Some copper sheet shown on the picture for some section on the top plate.

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Tags: Aikido, chassis
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Posted on Friday, 15th July 2011 by Auw Jimmy

The upgrade not yet ended. I still have something to finalize my Aikido PreAmp. I go to upgrade some section in order to make it firms before fitting it on the new chassis.

Here we go. First, we will install the affordable grade IEC from Furutech, the Rhodium plated FI-03. Fuse holder integrated there (oh well, which fuse shall I use?). That’s gonna be another question.

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Tags: Aikido, Cable, Cardas, Duelund, Furutech, Kimber, resistor, Vishay
Posted in Collectible Stuff, DIY Audio | Comments (12)

Posted on Tuesday, 12th July 2011 by Auw Jimmy

Not just Lundahl here, I also ordered custom choke from Jack/Electra-Print. I contacted Jack and asked him to create a Choke, with requirement to be placed in Input position. He offered me a VPI technique which (according to him) enough for Choke Input application. Other requirements was a “jimmyauw.com” standard which mean oversize construction (M6 lamination, 30H/75mA).

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Tags: Choke, Electra-Print
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