e65

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....

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.

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?

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...

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.

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.

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?