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

Tuesday, November 27, 2007

nokia n810 internet tablet

who needs an internet tablet when you have macs that boots up so quickly, ready with wifi during OS startup?

well... of late, safari keeps misbehaving, giving me the black translucent screen of death. this is the equivalent of the windows blue screen. there's nothing that can be done except to reboot. evil... and it happened to me twice last night. hardly something that i expected from OSX.

the debian-rooted OS on the N810 is well behaved so far.

truely an internet device, with shortcuts for popular websites such as facebook, wikipedia, some google sites such as maps, blogger, picasa, mail, etc.

built in sip client is ok, just that it does not handle call waiting. can do video calls out of the box. quite acceptable quality too.

has an open source application development community, browser handles flash content, built-in media player can play internet music from all over.

nicely built device with a foldable stand. long standby battery life.

built in IM can handle Gtalk, Jabber and SIP protocols.

more pics here

Saturday, October 27, 2007

Feedforward Shunt Regulator again

I redid the Shunt Regulator again. One channel seem to "runaway" when switched on for a while. This caused some speaker cone movements even when no source is playing.

Measuring the incoming supply, the voltage between the two 10M45S, and the output voltage, it seems that only one of the chip is giving this problem. Looks like the small heatsinks are not enough to dissipate the heat, resulting in thermal runaway... i think this what it is called.

So, i did it using plain old point to point wiring on a spare heatsink that i have. This new version will be muncho mancho enough to take the heat, else nothing would. ;)

During testing, the voltage did not fluctuate much. No runaway this time. Cathode resistors measured spot on at around 2.98v. The 10M45S are sourcing around 10mA per chip as per specification. It's just that the 10% coffin resistors are not accurate enough to produce equi-voltage between L and R. I may have to measure for a pair that fits the bill.

Maybe I should start digging for my 2k2 vishay power resistor somewhere in my box...

Thursday, October 25, 2007

Mozzy Mozzy Bite Me!

I'm sure lots of people heard of the mosquito ring tone being used by teens in schools so that the teachers are none the wiser when their phones ring.

Well... i took the mozzy test just now... It's supposed to be at 17kHz. Try it here in mp3 format.

And let the result be out... I am 17kHz deaf.

Now tell me about those audiophiles that swear by the super tweeters... Are they crossing them too low?

And tell me that my Diatones do not reproduce highs... Well... it does not bother me if they start rolling off at 18kHz or so.

Bite me, but the mozzy ringtone just proved me right... that i do not need a speaker that goes from 20hz to 20kHz, nor super tweeters.

Saturday, October 13, 2007

John Broskie's B+ feedforward shunt regulator

i've actually got this board done up before i shifted. that must have been 3 or 4 weeks ago. i was even comtemplating putting it into my 5687 preamp the day before NoiSing07 so that i can demo the preamp with the regulator.

good thing that i did not... it took many attempts before i got it to work. most of the time, i burnt resistors as i forgot where the ground of the board is cos it was sooo long and i did not mark the board with symbols.

i also killed quite a couple of 10M45S chips. it seems that even though it is sourcing 10mA, heatsinks are still required on the chips.

it seems that the regulator added a sense of scale and resolution to my soundstage. it is easy to pick out details... very resolving. also, the bass seems to have benefitted by being more controlled and detailed. not quite sure how to put it, but i would say that this is worth the effort.

perhaps other HV regulator designs would produce the same effect?

the circuit is based on Jon's feedforward shunt regulator.

parts are swapped below as mentioned:
1. first dropping resistor after B+ as 1k2 10W instead of 309R
2. second dropping resistor after B+ as 2k2 10W instead of 614R
3. B+ is 290V, between dropping resistors is 228V and 136V (L channel)/140V (R channel)

Sunday, October 7, 2007

A trip to Chek Jawa

It was raining on and off. We left home when it stopped raining and the sun was out.

A boat ride from Changi Village to Pulau Ubin is $2 per person, regardless of age. Another $2 per bicycle.

Upon reaching Pulau Ubin, a van ride to Chek Jawa itself is $2 per person, regardless of age. It's a 10 minute ride. I am guessing a walk would take an hour odd because of terrain.

The van does not go all the way in. We have to continue on foot to the Chek Java Visitor Center, which is a less than 5 mins walk. We started the trail around Chek Jawa starting from the Forest boardwalk. This will lead us to the Coastal boardwalk, then to the Chek Jawa Visitor Center.

Some of the resident lifeforms were not spotted, but i guess not everyone spots everything at the first go. Heard from my wife that her friend did not see anything in the few times she was there.

I find the place a little over-hyped, but nonetheless, it is still a good idea to have a wild life preserve. At least Lucas's generation will have some nature to see when they are older.

Some pics here.

Tuesday, October 2, 2007

Poem for a lost child

We had a miscarriage 2 weeks ago. The operation was on 28th September.

My wife wrote a poem that moved me to some tears. I was in the middle of a partner hosted lunch when I saw it on my Blackberry.

I asked if she was ok, and if I should put in on my blog.

Here it is, something for us to remember her (she was sure it was a girl) by.

You Left

I knew it was you
I knew your name
I could feel your presence
Long before you came

I wanted to hold you tight
I wanted to keep you safe
Embrace you with love
Nurture you with faith

You did not stay
You did not wait
I did not know you left
Was I just too late?

So many questions unanswered
Appointment you had to keep?
Had you something real urgent?
That you left me here to weep?

Had I known, had I known
If only a farewell bade
I did not know you left
I was just too late

Saturday, September 29, 2007

Room is done... more or less...

So the room's more or less done. One thing that I really want to change is the door. It feels light and does not stop sound. When I listened to loud volumes, everyone outside can also hear what I'm listening too. The same goes when Lucas is playing outside... I can hear him during soft passage.

Sigh... But the colour of the door matches the cupboards and speakers... Soundproof doors normally are those darb metal clad ones that look like my store room. If only the store was large enough to fit my audio gear and have a space suitable for listening...

Updated pics here.

Saturday, September 22, 2007

Diatione PM610 with veneer

After a failed attempt to veneer the speakers over the National Day weekend holidays, I sent the speakers to Robert's place for veneering with my zebrawood veneer. They did a much better job than I could ever accomplish.

Will be transporting the speakers back later today. Room should be setup and ready for music. The sofa to be delivered in an hours' time. ;)

Tuesday, September 18, 2007

Diffusor Wall installed

I posted an entry regarding the diffusors that I got in a mass order from an echolofter some time ago. This post is an update on the progress so far.

It was a hectic one week with packing, shifting, unpacking and cleaning all thrown in. In the midst, I think I have misplaced my Opus3 turntable power supply. Looks like I have to DIY a beefer supply for this table now. ;)

Anyways, here are some pics of the room. New pics will just be added to the picasa folder.

Sunday, September 9, 2007

Thank you for the Noise!

The much anticipated event on the local audio calendar is finally here... NoiSing07, on 8th September 2007. Not having a NoiSing in year 2006 surely must have created a void as the displays in NoiSing07 is easily the best of the 3 we had so far.

The venue was Republic Polytechnic. We had two rooms, one on level one, the other on level two. Accoustics was to die for. In my opinion, Level two had the better of both rooms. It is meant for panio practice. Fully treated even on the ceiling. This room was dedicated to Solid State gear.

On level one, we had the tube gear, and easily the larger crowd of both rooms. This year, we only had one full range single driver speaker, represented by the famed Freastrex driver, courtesy of Willam Ang.

We had quite a few preamps, two Audionote M7 designs, one other that I'm not too sure of, two Akido preamps, a Sakuma Tube buffer using 211, and my 5687 with Tamura output transformer.

The main eye candy is the speakers... Ken helped setup the electronic crossover to enable a three way system using his Dukane plasma tweeters, Maxonic fieldcoil horns, 340hz Azura with TAD2001, Karlson bassbin with 18" JBL drivers, 15" Altec BR box...

For the actual list of components, take a look at the echoloft posting.

Both rooms had great sound. I was impressed by the ML preamp in the Solid State room, with a virtual control from the laptop. Eusof's (Synthesis) Vifa speakers, although bookshelves, turned out to be a beast to tame when we heard the solid state amp happily clipping away. It produced astouding sound when driven at moderate volume. Had to do a double take to be sure that the Orions are not playing. The 3 way setup at the tube room was equally astounding, given the 5 mins tuning of crossover by Ken. There was a distinct lack of amplifiers. I thought Ken joked with me when he mentioned that he was waiting for me to bring amps.

All in all, a great way to spend a Saturday. Really enjoyed myself there. Unfortunately I was not able to stay all the way till 6 odd.

Kudos to the organizer (Johari) and all those who helped in this event. Mervin (MB) did a fine job by helping us book the rooms at Republic Polytechnic. A big clap for all those die hard DIYers who brought their geat to RP! The morning rain was not enough to stop us!

More pics here.

Monday, August 27, 2007

Not enough of 881?

I have some feedback that the ringtone that I extracted is too short.

Did some over the weekend but was not able to upload the files to Google Page Creator from Safari. So here's the two mp3 versions.

One Half.
One Half, Duet Version.

Thursday, August 23, 2007

Royston Tan's 881, 一人一伴 ringtone

I keep hearing this One Half song in the office until I feel like I am haunted by it somehow... Even when no one is humming it, it is being replayed in my mind like an endless loop.

So, I went to get the cd over the weekend... To my horror, it is sold out at Sembawang Music in Bishan. Luckily the shop opposite had around 5 copies of it left on the shelf.

I went home and downloaded some freeware to edit the starting hokkien phrase into a ringtone suitable file.

So, for those interested, you can grab One Half ringtone here.

Sunday, August 12, 2007

NDP 2007 at Raffles Quay

That's one of the places for those not able to get a ticket to catch a glimpse of the show. There are lots of people, but the view is still ok.

Lucas was there to catch the helicopter and jet flypast, as well as the fireworks. As usual, there are lots of human traffic once the fireworks are over. People in all directions trying to get out of Raffles Quay.

We managed to go over to Lau Pat Sat to catch a bite. We then had dessert along Cross Street before heading home.

On the DIY front, things are less rosy. My attempt to veneer the speakers ended in disaster. The veneer did not stick completely. There were air pockets within and at the edges of the veneer.

I decided to undo the veneering. I had to remove 2 pieces of veneer from the cabinet and then sand it down using the Makita Finishing Sander (B04540) that I bought a day before.

I think it is partly due to the veneer that I got... it is one of those reconstituted real wood veneer... that means wood that is processed to be made into veneer. It is not completely solid, but has a horizontal grain that can be easily broken...

Will see if Robert can help me veneer this pair of speakers... hopefully before end of next month...

More pics of Lucas' NDP outing here.

Saturday, August 4, 2007

Diatone PM610MB driver

i've actually got my zebrawood veneer some time ago, wanting to veneer the pair of speakers... but always am either too lazy or caught up with other stuff.

since there's some holidays coming this next weekend, plus my in-laws are not around, it is the best time to start on this project.

the diatone pm610mb is a pair of 6" vintage alnico drivers from mitsubishi. out of production since 1997. the M series was introduced in 1995 as the 50th anniversary edition of the P610 series of drivers. there's more information availabe at Audio Nautes, an Italian DIY audio site.

i got an enclosure to be build according to Kondo-san's design for the PM610. surprisingly, the bass is quite good. not sure if it really is around 40hz, but it surely suffices.

now, all i need is to shop for a belt sander. ;)

more pics here.

Tuesday, July 24, 2007

Downgrade for the better?

seems counter-intuitive, but that is exactly what i have done.

i sold my canon 350d on 2 days ago to a new DSLR user. prior to making the sale, i only sms the person and had not called my potential buyer. i also got lots of sms and a caller wanting to deal at a higher price than what i agreed upon. i told them that i am meeting a buyer and is not nice if i turned this buyer down. i feel it is only right that i give the person i am meeting "the right of first refusal". my buyer turned out to be a young girl who is doing her internship in a consulting firm located in Clarke Quay... from the way she held the camera in the shooting position, i can tell that she is an amatuer. i gave her some quick lessons and offered to pass her my 350d book that i bought on a whim at a later date.

anyways, after the sale, i stopped by ms colour to get a ricoh gx100 at SGD999 (SGD1009 plus lcd protector) as a replacement... well... i have to get a camera to take pictures of lucas right? hahaha.

immediately, i thought it was a bad move... the 350d was quick to write raw images to the CF card. had no lag during the write phase, can take fast moving shots. the gx100 is not able to stack up to these abilities. the gx100 has some write delay of 4 odd seconds when doing raw. requires the external view finder to be mounted in order to simulate a SLR. when the view finder is in use, the hot shoe would not be usable for an external flash unit.

however, the gx100 has real good marco capabilities that my sigma lens can never better (well, it is not a marco lens in the first place)... or would cost me an arm and a leg to purchase a marco for the 350d... plus i would have to lug around more gear. the gx100 also has quite good picture quality. guess i will need more time with it before i can fully appreciate it's beauty like others could.

i think the gx100 would allow me to take more pics of lucas without having to bring along too much stuff especially when on trips. i remembered i delibrately did not want to bring my dslr when we went to KL... let's hope the gx100 will change things for the better... photography is more skills than equipment right? hahaha... (a parallel to audio equipment as well?)

above pic is done using macro mode of gx100.
more pics here.

Monday, July 2, 2007

Great job HPDB!

Lucas was at Bedok Resovoir Park on Saturday to cheer the HPDB team in their qualifing heats in the 800m Corporate Men's category.

the HP dragon boat team came in first and second at the Bedok Resorvoir Park yesterday during the finals. since the team came onto the dragon boat scene last year during the Singapore River Regatta, it had won Gold in every open corporate race it participated in locally.


it is no mean feat and is testament to the training the team puts into race preparation every time. it is safe to say that the team is the one to beat in any corporate race. the fact that HP teams are in a corporate race would signal stiff competition to others.

keep it up, my fellow paddlers!

for more pics of the race, please check out Kam Meng's flickr set.

Sunday, July 1, 2007

The A-bike

I'm not sure what led me to look for an A-bike... but the main intention was to have a bicycle that i can store away when not in use, and to be able to accompany Lucas when he is cycling.

Then I saw the Strida that was being sold in a store at Adelphi duing one of the walk arounds to check out hifi equipment in that building. The Strida was selling for around SGD800 if I am not mistaken. Quite a hefty price for a foldable bike. And it does not fold down to a small size. There is a youtube video that compared the 2 bikes.

The A-bike was designed by Daka Development, a SGX listed company, based in Hong Kong. The ironic thing is that the bike is not sold in Singapore... Shipping to Singapore would be 1/3 the bike price. Since my wife is in London, I asked if she could lug one back for me. Actually, prior to her trip, I told her it is not necessary to get one.

Anyways, she was nice enough to lug one from London to Berlin to Brussels to Singapore for me. I started riding it since yesterday. The short handle bar makes it difficult to maneuver the bike at slow speeds. Need some getting used to... The wheels also felt a little bouncy despite it being inflated till 90psi as recommended. And it did draw some attention when you are out cycling. Mostly because of its diminutive size. When my wife rode it in London, the people there thought she got it elsewhere as they had never seen this bike in London before.

All in all, a nice fun bike in a small package that will keep me from any DIY stuff this week. ;)

More pics here.

Friday, June 29, 2007

Does size really matter?

I have gone thru the quest on paper to look for a small enough speaker cabinet to be used as a bass or sub-woofer unit some time ago. This has shown that besides the driver characteristic, the only way to get it to go lower is to increase the box size. There is a limit of course.

When I first saw the above box with the Fostex FE207ER-S at Robert's place, I was not expecting it to sound any way decent at all. Thereafter, I just continued to look at other stuff, such as the DAC that he has been experimenting with... he was telling me about the different low noise power supplies that he tried in various positions, which sounded nice at which part, etc... Then he started playing music thru those small boxes above the horn loaded speaker.

To my surprise, the mid bass is there! Based on memory, I did not think that it went lower that those horn loaded Fostex, but the horn loaded boxes are a multitude larger. Even though I had a flu which caused my hearing not to be what it normally is, but no doubt, it is still acceptable frequencies available from that small box (think small bookshelves, but with more bass). I cannot help but wonder why I'd want to have a low WAF speaker... should just get a small box with a sub instead.

I also wondered if the same box will work for my Coral Beta 8 driver... Please do not tell my wife about this pair of gem that I have squirreled away... But I am sure it will get the stamp of approval from her in such a small cabiinet. Maybe I should suggest to Robert to make it deeper so that it can accomodate the larger magnet of the Beta 8. ;)

Some pics here.

Thursday, June 28, 2007

mod done... and about time...

seems a long time since the last update... blame it on CommunicAsia 2007 plus the fact that my wife had to go on an overseas work trip to Europe for 2 weeks... leaving me to fetch Lucas and entertain him in the evenings and the weekends.

well... i did find some time on Sunday to finish up the output filter mod... but only on one channel. i reused 2 kiwame 30k resistors that i had together with some Blackgates that i got from my favourite DIY store... Ahfartaudio at Upper Cross Street. they have one of the lowest pricing around. i initially wanted 4.7uF BG NX, but he only had 1 left. someone else took out a bulk order for 1000 pieces or something like that... robert then suggested that i do an e-cap configuration with 10uF BG NX instead. since i have not tried this configuration before, i took up the offer... this places the cost of the caps at around the cost of the PS1... add in the PS1 remote controller that is on the way from ebay, future linear power supply mod and a casing, i think this project will breach SGD100++.

i did a quick sanity check with the PS1 to ensure that i did not screw it up. with a laura fygi cd on the PS1, connected to the TA2020 tripath amp and one speaker, i fiddled around with the controller and music was playing. don't ask for comments on sound... the speaker is crap, so anything coming out is crap. it has bass that is loose and not listenable...

doubt i will have time to test it out properly this weekend as my wife is bringing back a toy for me on Saturday. hee hee hee... might be too busy with this new toy. ;)

more pics here.

Wednesday, June 13, 2007

Sliding Bench...

A misnomer it must be.

Not sure if it is the need to be seen as embracing avant-garde designs or just trying hard to be stylish, but the metamorphosis of Dhoby Ghaut MRT brought about by Dhoby Xchange must have gone into the heads of those SMRT folks for them to justify buying those circa 26" metal benches that are placed close to the wall, with a slight tilt on the seat and a smooth finishing on the surface.

These seats are impossible to be sat on as it will cause you to slide forward and eventually fall off. Those who can master the legwork to keep from falling may well be giving their legs a much needed workout.

But i've observed with much amusement, people trying those benches, only to migrate off to the traditional marble top benches what is not just more comfortable, but stable and not as frustrating.

Maybe the only reason why they had this installed is to amuse the kids, as Lucas will demostrate in the below clip:

Give me a wall instead... and I'll gladly lean on it...

I think as far as sitting objects with amusement value is concerned, the head honchos at NLB have scored with flying distinctions with their Italian plastic chairs in the kids section at basement one, central lending library. These chairs can be sat into normally, and if turned on their front, it can be used as a rocking horse. But the customer service there is a fine example why we would never reach service levels like Japan.

Sunday, June 10, 2007

Modding the PS1

I spent some time to carry out the suggested modifications at Mick Feuerbacher's site. I did not have the correct capacitor value for the output stage replacement, but since the PS1 is stripped to the pcb, i took the time to perform the other mentioned mods such as removal of the dc blocking capacitors after the DAC, and also removal of the muting transistors. I also removed what looked like the mod chip. Initially I thought it was removed as I did not see the same implementation as shown here.

Looks like different shops mod the sets differently. ;)

Will get some small value blackgates for the output stage replacement... Not sure if I can listen to this next week as I am expecting to pick up some Zebrano veneer for my speakers.

Some pics here.

Saturday, June 9, 2007

A/B impressions of PS1

The anticipation of this moment since early this week... i pulled together my horses and men for this session. The other source is a Marantz CD50 using a TDA1541A dac. My 5687 preamp, d3A/VV302B DRD amps and my Diatone PM610MB speakers were called to duty.

Sequence of A/B is always PS1 first, followed by CD50 for each track.

Discs used are 1 - Plastic Flower from Op4, Lena Park (Korean Artist), 2 - The Power of Love Songs CD1, Fish Leong (Malaysian Artist), 3 - The Hong Kong Hifi show CD (2007 I think), 4 - You'll Hear Better Songs and Memphis Tennessee from Early Hours (Hybrid SACD), Eleanor Mcevoy.

Impressions are that the PS1 presents a lower output voltage to the preamp, the bass is rounder and not as profound, soundstage is less deep, and it has a more mellow presentation when compared to the CD50. It also seems veiled in comparision, with the CD50 giving a cleaner and clearer sound.

Perhaps after the mods, it will be better... I can only keep my fingers crossed.

Tuesday, June 5, 2007

Direct Reactance Drive

A long overdued post. You might have already seen the pics at my picassa albums.

This project actually started out in June/July 2004, and was my first attempt to build a tube based amplifier. On hind sight, it was a little ambitious to build a 300B mono block as a first tube project. Nonetheless, there are people who did it. Me, I only got it right on the second attempt.

Inspired by Sakuma san and Josh Stippich, I wanted to make use of those nice mercury rectifiers in my circuit. The RCA83 was bought locally at a rather high price. Netting these tubes on ebay would cost a fraction of what I paid.

I did lots of reading about tubes, and also got some online education of such stuff at DIY Audio. The Net is such a wonderful tool... I even attempted to create a DRD calculator in excel that helps calculate the resistor values and B+ required when certain inputs such as driver and power tube operating points are furnished. I was suggested to use the Siemens c3g as a driver for the 300B tube.

Suffice to say this this first pass project did not pass with flying colours. With a pair of inefficient (87db/m?) Totem 1 bookshelves, hum was evident even at 1.5m away.

I rebuilt this amplifier around Oct/Nov 2006. This was also partly due to reading the success of Luis Gascón with his DRD using d3A/300B on I built my version with d3A as the driver, but using LED biasing.

Testing this on my Mitsubishi Diatone PM610MB speakers (around 93 to 94 db efficiency), hum was only evident when my ears are around a feet away from the driver. All heaters are using AC for this build. Needless to say, I am very happy with my DRD amplifiers. ;)

More pics here.

Monday, June 4, 2007

Found... the elusive... PS1

Like they always say... Persistence pays off. This is quite true when I managed to find a Playstation 1 at a Cash Converters for SGD29 with 2 controllers, AV cable, one memory card and a power transformer for 240vac to 110vac.

This particular unit that I have is labelled a 100vac version. The store assistant asked if 100vac was ok. I immediately told him that I am ok. He then commented that I'm a confident customer... Actually I was thinking of building a PSU for the 7.6vdc and 3.6vdc that would be required by the unit.

When he brought the unit to the cashier, he also went to collect the accessories. It is in this bag that I spotted a transformer that seem to indicate 240vac. After paying, I went off to find a quite spot where I can inspect the bounty. And I was spot on. ;) It was indeed a step down transformer.

The moment I went back, I plugged in the AC and powered it up. The green LED was lighted. Hurray... I quickly did a test of the audio via the TV. Seemed that one channel is ok, but there was some hum. Perhaps due to wiring. Will do a real test soon.

Since the serial number or identifier sticker at the bottom of the unit is removed. My next instinct was to open the unit to determine if this was the real mccoy. I did not realize that the dac is actually quite small. I had to strain my eyes to verify the numbers on it. It was indeed the Ashahi Kasei Microsystems (AKM) AK4309AVM DAC 16 bit Stereo Delta Sigma chip. This mean the PS1 that I have is the SCPH100x version.

My next steps would be the output stage mod and the PSU mod as mentioned at Mick Feuerbacher's site. Let's take a real serious listen to how good this thing actually is. ;)

More pics here.

Sunday, June 3, 2007

The Last Sonic Frontier?

Probably the most neglected area in one's pusuit of audio enjoyment... and this would be sound treatment of the listening room.

The conundrum for me, then, is... how would you know what to use when planning for a new room? Especially when you have never heard your system in it before.

Well... perhaps a leap of faith and some reading. ;)

Initially I wanted to DIY something like the RPG Hemiffusor. There's a website that had the dimensions to do this. But I think this woud be a real time consuming affair...

The diffusor seen above was purchased as part of a mass order offered by joamonte on echoloft. I took me around one month before I finally pick up the 8 diffusors from him after he told me that they are ready. It was a late night affair when I made the pickup. I had the fortunate experience to listen to his system. It was really good. It is definitely showroom material... in fact, showrooms should take a leaf out of his book.

I might be adding some diffractal for the front, but now I am having problems with mounting 8 diffusor panels... not enough space in my odd shaped room. Perhaps I will go with 4 at the back and have a hanging ceiling for the other 4.

Rest of the pics here.

Outing at Lower Pierce Reservoir

After breakfast at one of the prata place opposite Teacher's Estate, we went to Lower Pierce Resevoir with Edna and her mum. Edna is Lucas' biting buddy in infant care. I think they express their liking for each other by biting... good thing the parents are cool about this. ;)

Now Edna and Lucas are at different child care centres. The only time that they meet is when we go out for such trips together. The last one was at Night Safari with Edna and her parents, and also Nathaniel and his mum, plus Lucas and us.

Some pics of the sunny trip here.

Wednesday, March 14, 2007

quick and dirty dac enclosure

a long post after some time... seems the new job is all work and no play. ;)
anyways, did a 12hr or less job on a dac enclosure that i had lying around for a loong time.

it is done using an eddystone RFI/EMI proof enclosure. one thing that i forgot to do was to put my cell phone in that enclosure and give myself a call to see if i get a missed call. hahaha...

the enclosure was given a pearl white coat, but unfortunately, this is a difficult colour to spray... need 2 cans for best results. since i had one afternoon to do this, i did all i could with one can. i then used a gloss coat as the top coat for this enclosure. results are far from ideal, but what the heck...

the dac is the original monica, ie, the tda1545 non os chip from philips. mine is powered using a 12v sla battery.

here's the dac photo album for your viewing pleasure. let me hunt down the shot with the dac powered on so the blue LED is showing...

Wednesday, February 7, 2007


since it's gonna be sold to the public in a week's time, guess it would not hurt if there is some sneak peek.

so, here's the nokia e65 dual phone for you...

very sleek phone that has quite a nice finish, slightly heavy feel, but i think that adds to giving an impression of a solid build. the colours are vivid and most importantly, you no longer have to shade the screen to see what is on it under direct sunlight... it is actually quite visible!

the only downside is that it is a battery sucker... 10 mins on the phone and the battery is real hot. handsfree kit usage is most recommended... don't want a battery that blows up next to you right?

the navigation key pad takes some getting use to, but should be ok if you use your nails to push the keys. keypad has less than usual tactile feel... which i thought was not too nice a feature... i personally prefer keys with some feedback... at least i do not need to look at the screen to know that my key strokes are really entered in a short message creation.

there was one night when having the wifi and voip turned on and the phone was flat in the morning... the voip quality, at least in singapore (mio mobile), was actually surprisingly good. there is a little lag time from when a person speaks till when you hear the actual voice, but this is not apparent unless the person is right in front of you... that is when you can actually see the mismatch between the lips and the voice via the ear piece. but free outgoing calls in the hotspots or home wifi to local numbers is a difficult deal to beat... and apparently it works in some countries too... as long as session initiation protocol is not blocked by the ISP.

more photos here, and here, and here, and here....

Tuesday, February 6, 2007

5687 preamp done...

and it's about time... since the holidays are well over and work has taken on the 4th gear. :P

an idea for a preamp that started off as a transformer volume controller, to a dht preamp, and finally to a noval indirectly heated preamp with output transformer.

and it turned out that i built the 5687 preamp with LED biasing and tamura A4714 output transformer. all these is with parts that are on hand... mostly...

even the chassis is made from aluminium that are lying around for some forgotten project... just so happens that the width of the aluminum plates are 10mm longer than the width of the A4714, making it a suitable candidate for a tower chassis... and so it is. for an easy chassis build, i got 2 MDF to be the front and back of the preamp. the pesky thing about 3/4" thick MDF is that it is a hassle to make a hole for any connector thru it...

the 5687 was wired as double sections to lower the plate impedance so that it will better leverage the 5k output transformer. heaters are in series, fed by 50000uF of elna capacitors and 2 paralleled LM317 set up for 830mA current regulation each. this gave around 11vdc. a little low as i used a common 1R5 coffin resistor for the LM317. maybe i should series a 1R and a R47 to achieve higher output current... but well... i have not known anyone who used tubes till they die of cathode poisoning... plus i used raytheon 5687wb and not the super expensive bendix 6900... so what the heck...

rca plugs for the input selectors are actually stripped from my neutrik rca from the m10 project. the output plugs were from canera rcas. volume pot is a 100k blue alps. signal wires are silver upocc wires, copper hook up are upocc copper wires, umbilical are multistrand 14ga upocc copper. all wires from ahfartaudio. in fact, my drd used all upocc wires internally. silver was used for signal path.

power supply portion was built on a hammond chassis meant for another forgotten project, using some handsome irons from nick chua. it is rectified by the rca 83 mercury vapor full wave rectifier, two 50H chokes and many 220uF philips capacitors.

future mods would be to add the constant current source that i implemently wrongly... which led to a loud bang upon power up, with bits of the transistor flying out. hahaha... ;)

here's a flickr set of the preamp.

Thursday, February 1, 2007

work and the audio lover

it just dawned on me that in my job history, i know of only one other audio lover in each one of the company which i worked for (at least in singapore context... well, i only know of one other audio guy when i was in US too...). is this a strange coincidence or are audio lovers/audiophiles a rare breed?

just look at the amount of messages flooding a local photo forum as compared to a local audio forum... perhaps audio is passé... the crowd has flocked to digital photography.

a colleague was remarking that there are more and more amatuer photographers moving into wedding photography as a sideline to bring in additional cash. digital photography has lowered the barrier to entry so much that anyone with 1 or 2 years of digital photography experience will dare to take on a wedding shoot. this is perhaps unheard of when analogue was king.

who would have dared to take a risk of shooting on film, a chinese wedding dinner, without knowing that the shots are nothing less than perfect? what happens if the film leader was not loaded correctly into the spool?

perhaps with the influx of class d or class t amplifiers, the audio scene will be much revived?

who would have taken a serious look at B and O when they have those lifestyle speakers and amplifiers? take a look today and people would be asking if an amp is ICEpowered.

so, how many audio friends do you have at your workplace?

Monday, January 22, 2007

bottletree park

what a unique name for a park in boring singapore. at least it is not named after a road. ;)
nestled in Chencharu Road, or being visibily prominent from a MRT ride to the Khatib station, this is a 7ha park that just recently opened. quite easy to locate if you walk from Khatib along the MRT lines towards the stadium (in the direction of Lentor Road).

it offers a large fishing pond, prawn pond and also an enclosed shallow water area for kids to try out "kampong" style catching of small fishes.

we brought lucas there to catch prawns in the salt-water enclosed pond. with a rod and some bait provided at the premises and a little bit of luck, lucas managed to catch 3 prawns within half an hour. the other half hour was spent playing with the fishing rod in the water...

if you are there, do check out the really huge fresh water fish at the little wooden bridge near the washrooms. they are really huge... you won't want to fall into that pond accidently...

Tuesday, January 16, 2007

murphy's law & DIY audio

seems like an inseparable part of life... one day it works fine, and the other it does not. worse, you have no idea what went wrong.

i was trying to hook up my 5687 preamp to the rest of the system that i intend to partner with, but somehow, the power supply of the preamp was giving me problems...

i have a switch capable of warming up the heaters first, and then switching in the B+ on the second toggle. somehow, at the first toggle, the rectifier let out a glow, meaning that something is wrong... powering it off, i measured 120vdc from the capacitors. this does not discharge even when i switched in the rest of the circuit.

maybe one of my crocodile clips on my temporary power supply are touching each other. don't have the mood to troubleshoot after i spent around 10 minutes to figure it out. i then took apart the supply and started work on laying out the components on a hammond chassis that i had on hand.

think i will retry the psu when i have the time, but this round, i will make use of my 22uF GE 97F oil capacitors. i have 4 of these which were used in paralleled configuration on my previous build of the DRD amplifier.

Monday, January 15, 2007

cram them in like sardines

that is what our public transport operator for the mass rapid transit (mrt) trains have in mind. according to them, the mrt is not utilized fully even during peak hours. there was a straits times report which had people actually agreeing to that...

strange... why is it that i always get the crowded train? i find that the north-south line tend to have commuters that don't give up their seat to the elderly, pregnant or those with young children. the north east line (nel) commuters are more gracious. usually giving up the seat upon seeing people who need the seat more than themselves. my wife thinks that this is because the people staying along the nel where we board the train at seng kang station, are usually the younger crowd. they would be those who bought flats in seng kang or punggol, living with their spouse and probably without a kid.

well... i guess when the nel population increases especially with all the condominium developments in areas such as kovan, woodleigh, potong pasir starts packing in the crowd, our train operators would be the ones who win.

anyways, i just wanted to post this youtube clip that i took of Lucas falling asleep on the train between novena and toa payoh station along the north-south line. one nice commuter gave up the seat seeing that i was carrying Lucas and his bag.

since we are on the topic of trains, i might as well mention that i happen to take one of the new trains about a month ago. it was pretty spacious, and had aircon that is blasting away. i guess this would be useful in peak situations to prevent commuters from fainting due to body odur, bad breath, the occasional farts, etc...

i happen to be on one of these "new" trains today and it was completely deviod of air conditioning... luckily i was onboard for a stop or two. i also noticed that the metal platform between the cabins was rather old... implying that the "new" trains could have been retrofitted or upgraded from an old platform. well... guess the mantra of "retrain, reskill, rehire" applies to trains as well as the workforce.

Sunday, January 14, 2007

why would you even bother to DIY audio equipment?

well... one reason could be cost... perhaps?? for example the wavac sh-833 monoblock amplifier would cost a cool USD350k in july 2004. ok... it might be technically close to impossible to clone that amp, but it might be possible to clone the wavac he-833 monoblock amplifier, similiar to the bigger wavac, but minus the elaborate power supply and at a much cheaper retail of USD47k... still no peanuts... or could be peanuts to some.

at least the DIY route will enable some enthusiasts to achieve the 833 single-ended sound in their rooms without breaking the bank for it.

one other reason is to be able to build equipment that uses lesser used or commercially unavailable components or design topology. in the case of tube amplifiers, there are tubes aplenty that are not used in everyday commercial offerings from big name audio companies... why is that so? well... i would think that they are not keen to sail in uncharted waters.

my motivation for DIY audio is the satisfaction of being able to build something that, when made to work, will bring joy to myself. also, i will not be able to sell these hand-crafted creations as easily and thereby curbing my cravings to repeatedly "upgrade" my audio chain. this is not to say that i will not build more amplifiers if i already have one though... maybe my place will end up being a storage for DIY audio equipment...

even in DIY, there seem to be an "accepted" norm to do things... take a preamp based on the 5687 double section indirectly heated triode that i am building right now. most people run this tube at a higher plate and bias voltage that i do. my design requires them to be operated at just 115v, -4v bias, producing 25mA per tube. this puts the tube in one of its' most linear regions as far as the datasheet shows. why then, would other DIYers run them at a much inferior curve? is it because of the herd mentality? because they have tried and tested all possible operation points and proved to themselves that the generally accepted parameters are indeed the best? or is it just because of conformance to the general rule?

why would you bother to DIY if it is not because of the ability to freely reign in design?

Saturday, January 13, 2007

where are the pics?

technology still does not make life any simpler...

take pics in RAW, go thru workflow, develop into jpeg, export pics, upload to flickr with measly monthly limit and 5mb per pic limit, post via blogger... WTF??... isn't there a one stop shop anymore? whatever happened to consolidation and M&As? what? the next step is to have disparate golems?

it takes forever to upload pics to flickr... even transferring pics from my Sandisk Extreme II CF card warrants a coffee break. i still remember the time when i was surfing the texternet using a 2400kbps USR modem and it was not too bad a wait. maybe things were less complex then. you just wait with bated breath to see the text that renders in front of your eyes in EGA colours. 512mbps adsl modem is just not enough for internet usage nowadays... and i'm no longer the avid gamer that i used to be... just imagine what LAN gamers feel when they experience a matrix glitch... next thing they know, they are looking at their corpse in 3rd person mode.

if my work is plagued with such unproductiveness, i'd be in deep shit... forget about the quad cores... give me super bandwidth anytime... and make sure it is a true mesh network... least we suffer another taiwan earthquake.

ok, enough rambling... check out this flickr set of Lucas at his childcare outing to the Singapore Birdpark.

Friday, January 12, 2007

welcome to the blogosphere

once upon a time, i was interested in everything new. technology, consumer devices, internet and all it's failings, etc... then came work, then came life... then it became how 24hours is portioned for all these, while still allocating some time to leisure and R&R.

so, now i'm looking for something that will enable me to post the nice pics of Lucas without having to maintain the website that i created for that very purpose. it's tedious work updating all those pics... just imagine one roll of pics from my EOS350D every outing to some where of interest... not to mention the casual shots with my Minolta Dimage X... and those quickie shots with the mobile phone. at the same time, i would like to publish stuff on my DIY audio projects, which could be of interest to fellow DIYers.

let's see how this new means allow me to do the above in an easy fashion. it's like outsourcing... now i don't want to code my website, but i want to focus on content, so i turn to this to handle all the time consuming coding... somehow, not sure if it is due to my safari browser, i only see spell check and add image on the top of the bar. even the CTRL thingies does not work. i still have to include HTML syntax as i type this... WTF?