Sunday, 14th March 2010.

Posted on Monday, 21st December 2009 by Jimmy Auw

Not really published on the market (at least not well spotted around big online webstore), but I manage to get a pair of it.

This is the CAST version of the Duelund Resistor. Well, for the Capacitor, the CAST definitely better (less ringing, so quiet, dynamic). How about this Resistor? Not sure though, plan to test it somewhere. Picture below is the 5W version.

castr

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Posted on Sunday, 4th October 2009 by Jimmy Auw

To simplify the answer, Bleeder Resistor is used to “short” the positive and negative rail on your High Voltage (B+) circuit. The main reason is safety. Without Bleeder Resistor, your capacitors will store some amount of electricity after your system turned off. This may result of hazardous shock if touched, accidentally off course ;)

This time, I change the old Bleeder Resistor (no brand metal film) into Kiwame Carbon Film Resistor with 5W rating. Here you go.

kiwame

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Posted on Wednesday, 23rd September 2009 by Jimmy Auw

I dig my parts bin and found some resistor values which I needed to upgrade my Aikido. I used three brands here, Riken RMG “Metal Film”, Shinkoh “Tantalum”, and Kiwame “Carbon Film”.

Lets fire up the soldering iron ;)

resistor

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Posted on Tuesday, 24th March 2009 by Jimmy Auw

Still remember my “silly” project, this one and this one? I think I will make it even more “sillier” than before. Watch out.

First, I’m thinking of testing my new Mundorf Silver/Gold/Oil on my Gainclone. This top of the line capacitor from Mundorf sounds promising. Before, I was thinking to try a pair of VCap. But since VCap only available in lower voltage (250-300VDC for value over 1uF), so I need to think multiple times to spend large amount of money for that capacitor. Well, with this 1200VDC Mundorf, I can use them on my tube amplifier. While for 250VDC VCap, my usage will be very limited. So shall we welcome the Silver/Gold/Oil?

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Posted on Sunday, 22nd February 2009 by Jimmy Auw

Some of people on the net says that Gainclone is one of the shortest amplifier in the world. Some people could make it less than 32 mm on the signal path. Check it here! But I don’t have any intention to match or compete with them. Remember, I do what people don’t, so don’t bother with what they are doing ;)

The parts, most likely, are my old stock. Most of the time, I use what I have on hand (and also buy some if I do really need that). So you can see a lot of mixed brand here. I try to pick the best from what I have.

The first thing that I do is, to install the input ground resistor. Not just because this is the most important, but simply because I need to put two resistor in a “not common” way. The picture below will explain more than what I can say. It’s Vishay S139 (similar with S102) Ultra-High Precision Bulk Metal Foil Resistors. It’s 0.01% tolerance :) So 11K is 11K, not with additional value behind the dot. I need to use 22KOhm, but only have 11KOhm on hand, so I use two.

Not a genius job, just put two in series and they will do the job perfectly.

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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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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… ;)

1_silmic.jpg

A bunch of Elna Silmic, around 16.000+ uF each channel for heater power supply? Are you serious, Jimmy? ;)

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Posted on Saturday, 28th June 2008 by Jimmy Auw

Hmm.. Today I receive some components which I’ve been waiting for ;)

Can’t wait to assembly it… BlackGate, Orange Drop, Sprague, Mallory, Wima FKP, Riken RMG, Vishay L6C, and Kiwame. Some Teflon also have arrived on previous day. Some M-Lytic should be on the way, while some custom made special order metal foil resistor still on progress (2-3 weeks lead time, since this is special “made-by-order” things).

Wish I have 26 hours every day (2 hours extra for my DIY project).

Now I just can see it first. Assembly it later.

mainan1.jpg

mainan21.jpg

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