Jimmy’s Junkyard

Tube Rectifier Filament Supply Selector

Posted on Sunday, 18th July 2010 by Jimmy Auw

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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Burn-in Rig Before Battle

Posted on Sunday, 16th May 2010 by Jimmy Auw

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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Duelund CAST Ag (CAST Silver) Early Hours Impression

Posted on Saturday, 3rd April 2010 by Jimmy Auw

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

cast-ag-testing

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Tags: Aikido, CAST Ag, duuelund, preamp
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My Aikido with Duelund CAST Silver Installed

Posted on Sunday, 28th March 2010 by Jimmy Auw

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.

1-transformer

Not a bad 45 minutes of work, huh?

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Tags: Aikido, Duelund, preamp
Posted in DIY Audio | Comments (11)

Custom Made Power Transformer for My Pre-Amp

Posted on Sunday, 22nd November 2009 by Jimmy Auw

I ordered custom made transformer to replace my old Aikido Pre-Amp transformer. Before, I rarely ordered a “finished” transformer (but prefer doing DIY one with my colleague). But now I’m thinking to try a “proven good” transformer (and considering doing some comparison of its effect).

Finally it’s done. The transformer consisted of few secondaries, to supply my main high voltage, the rectifier, and the tubes.

trafo_setiawan_2

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Tags: Aikido, preamp, transformer
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Pre-Amp #26 Parafeed – Tweaked with Jensen Copper Foil Paper Tube

Posted on Sunday, 22nd November 2009 by Jimmy Auw

I visited my friend’s home few days ago. We planned to tweak his #26 Pre-Amp (with Parafeed design).

His Pre-Amp was a high quality pre-amp, in terms of parts and design. As you can see below, the high voltage section has Black Gate SKZ capacitor.

He just finished tweaking the high voltage section by adding 3 huge Russian Teflon capacitors (FT-3) and got significant improvement on the sound staging. He was poisoned by the VCap Power Supply trick as I did on my pre-amp, so he tried the cheap Teflon solution first, the Russian FT-3 before going down deeper with VCap

26-jensen

At first, his #26 used Jensen Capacitor Aluminum Foil. The overall sound is live, fast rhythm, and dynamic. A little bit less sexy on the vocal side for my taste and the top end detail was a little bit “flat”. Then we changed to Jensen Copper Foil Paper Tube. How did it sound? Keep reading.

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Tags: 26, jensen, preamp, preamplifier
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VCap TFTF on Power Supply Test

Posted on Sunday, 6th September 2009 by Jimmy Auw

Yes, you might call me crazy! A Teflon VCap TFTF on Power Supply section?

If I need to make myself clear, this 0.47uF/600VDC VCap TFTF Teflon capacitor will cost you around US$ 150 each (depends on quantity). So we will spend near US$ 300 only for two VCap TFTF here!!!

And eventually, you will ask why do I put those caps there? Actually this is an “accident”. I bought those VCap few months ago, but it just didn’t match right with my current system (it prefers Duelund CAST PIO) – check the article here, here, and here. So what should I do with them?

vcap

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Tags: Aikido, power supply, preamp, VCap
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Another Aikido Pre-Amp Mods

Posted on Sunday, 23rd August 2009 by Jimmy Auw

Never ending tweaks and mods? Yes I think so. Actually, my Aikido Pre-Amp already sounds good. But as a DIY, I think the journey never ends. Tomorrow always comes with another mods. After completing the PSU mods with Mundorf MCap Supreme 3.3 uF/800VDC and ASC X386S 40 uF/440 VAC here, I decide to go further with some other components.

First, I still hear small hum. This is mainly caused by the Filament/Heater Center Tap of my DIY transformer is not exactly on the center. So the 1/4 B+ isn’t injected on the correct Center Tap position. The only solution is to create a Virtual Center Tap with a pair of 100 Ohm resistor. I use 100 Ohm 5W Kiwame. Some people may say that you can use any cheap resistor for this purpose, but I always choose the best price/performance. At US$ 2 each, Kiwame fits this job perfectly. Make sure you use an accurate resistor (metal film should fit best, carbon film also ok).

psu-divider

I fire up my Aikido and ta-da… no more hum, even when my ear next to the speaker! But I need to confirm later with high-gain amplifier. With a normal/standard gain amplifier, the hum is usually less noticeable.

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Tags: Aikido, DIY Audio, Duelund, Kiwame, mundorf, preamp
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Aikido High Voltage/B+ PSU Mod

Posted on Monday, 29th December 2008 by Jimmy Auw

From my previous Aikido project, I’m still thinking of improvement of my B+ PSU. Well, I still hear a small hum. There are several possibilities to be tried, but I’m thinking of improving my B+ PSU first. If it fails, then I will think another way

From the LC-LC filter used before, I’m moving into a more filtering. Well, I’m talking about another stage of LC, creating LC-LC-LC filter. Previously, I used two Samhwa 220uF/500VDC capacitors. It’s a nice price/performance capacitor – I have to admit that. But, I need to change into a higher level (to see how much the improvement).

First I remove two Samhwa capacitors. It was a tiring job to remove those two capacitors (phewww). Then, I change the first capacitor with Korean “Motor Run” Oil Capacitor (60uF/400VAC), second capacitor with Mundorf M-Lytic 560uF/400VDC, then finally with another Korean “Motor Run” Oil Capacitor (40uF/400VAC).

Well, don’t ask me why I use this Korean “Motor Run” Oil Capacitor. It’s simply because I have no budget. If you have enough bucks in your pocket, go with ASC Oil Capacitor then