Friday, December 28, 2007

dangers of DIY audio

i suppose we, DIY audio enthusiasts, will one time or another, injure themselves inadvertently. whether it is a jolt from residual voltage in capacitors of a 1kv supply, or the soldering iron dropping on the foot with the hot tip facing downwards, or running the file onto your hand while filing some metal piece... it's my turn today... again...

i was trying to drill 28mm holes with a hole saw at robert's place when it happened. the hole saw was stuck, causing the 3mm aluminum piece to be caught in my wedding band as i was holding onto the work piece with my left hand. the drill press then pulled my left arm around the drill bit. my instant reaction was to hold on to the work piece with my left hand already at the 12 o'clock position. luckily i was able to hit the stop button with my right arm...

i had to use a pair of pilers to compress the ring back into shape in order to remove it so that i can wash the wound. the skin of my finger was sliced through. i guess it was deep enough that i could not feel any pain when washing it.

robert passed me some anti-septic and helped me handiplast the finger. chong helped me with all the 4 octal holes of the moskido instead.

hmm... i wonder if i can do the chassis work tomorrow with only one hand.

pic of the wound here if you are interested.

Tuesday, December 25, 2007

what's in a name?

apparently lots... especially if it has to do with branding.

i recently completed a power filter for an audio friend. he wanted something like the shunyata hydra design. it is actually a simple design that uses one X2 capacitor across live and neutral of the power socket.

this is a customised version according to the application in my friend's system. it has two IEC outlet instead, for a CDP and a DAC. the X2 capacitor is a huge RIFA capacitor costing $3 odd from RS Singapore. the cable is a UPOCC power cable type from neotech, the enclosure is a germany made IP66 rated unit. the cable connector is of some ceramic material, also made in germany. the black connectors at the edge of the enclosure ensures that the cable is crimped properly.

there was another cable done, but i do not have the pics for this as it was delivered earlier. it was just a straight cable with the RIFA X2 capacitor in the middle.

some pics here.

lucas's 3rd birthday party

lucas had his birthday party on 23rd dec 2007, a sunday.

some of his friends from infant care and childcare came over to join in the fun. the only mishap happened when san fell with the birthday cake when bringing the cake to the function room from the cake shop that was just down the road.

well... i guess worst things could have happened... like a fire in the function room?

more pics here.

how little ripple is enough?

0.002vac is the resultant ripple at my preamp after the second 10M45S chip. at B+, it was 0.009vac, and between the two 10M45S, it was 0.008vac.

Seems like one chip alone is not enough. Two together resulted in around 77% drop in ripple in my high voltage supply to my preamp.

I guess 0.002vac is good enough?

The measurements can be seen here.

Wednesday, December 5, 2007

this is a hilarous site. serena sent a link with raphael, wee wee and myself as a xmas card.

damn funny... but there are no elf girls in this card... whatever happened to lorien and arwen (liv tyler) in lotr?

you may want to do one of your own.

check this one of lucas, san and myself at

Monday, December 3, 2007

mods to 5687 preamp

finally the feedforward shunt regulator design taken from John Broskie's blog is incorporated into the 5687 preamp.

it is now providing dc with minimal noise to the circuit, biasing the tubes at 22.2mA per tube.

will try to post a hand-drawn circuit of the implemented circuit later.

more pics here.

zoo trip again

we went to the zoo again. my colleague was asking me why i went to the zoo.

my reply was that "there comes a phase in life when you keep going to the zoo". i was once a member of the "Friends of the Zoo". we paid a hundred odd dollars for an annual subscription, but in that year, we went there like 3 or 4 times. of course, during that time, we got newsletter from the zoo about the animals and activities.

the zoo seem to have two major attractions in june 2008. maybe that will be my next visit. i also seem to recall that the last KFC that i had was in the zoo.

more pics here