Cockatoo Conference Call

Cockies Concall

Its a whole perfect universe for the cockatoo.  I call the bird a kind of spirit bird, I never see baby cockatoos, I never see old ones.  They seem to live forever.  I know people who owned cockatoos through five human  generations or so. They all look the same, they make a stack of noise when they all fly in low together or sporadically to join each other, often in the same tree.

But why do they just all turn up one by one and sit in the tree for a bit, squawk to each other loudly, and then just take off… one by one again.. squawking as they go ? mate .. why ?

Well I guess they already know what they want to say, they just turn up and say it loud as they can.  I don’t know how any of them here anything the other is saying.

Do they look at each other ?

Nah.. they just sit there making a heap of noise, looking all the same in their white cockatoo suits, saying the same kind of things, and then leaving without as much as a see you later..

Right mate, guess you’re right there.

So what happens next day ?

Next day, same thing, same time, same tree, all of these cockatoos turn up dressed for a meeting or a conference of sorts, once again, some early some late, have a bit of a chat, a discussion, an argument then all leave again.  Nothing seems to get decided sometimes, and other times its as if it’s all a foregone conclusion mate…

Mate it is a conference call, same thing, you know, you get on the call, without so much as a by your leave, someone is talking, someing is joining, someone is leaving, and someone is saying something

Yep, and some of their lines only seem to work one way, like a vox mechanism. When someone is talking and just struggling to make a point, you know, keeps saying and this, and that, and, but anyway, you cannot interrupt. We all like to interrupt and make out points which just go into thin air, everyone else can hear us, except the person talking.

So yeah, cockatoos meeting is like the modern day conference call.  We all look the same, since we can’t see each other, we all turn up in our suits and leave at will, and what we say, kind of just repeats.  We turn up again the next day and say the same things again.

Oh Sure, we are definitely making progress.  But I think the conference calls just make it so we all feel ok about what we are doing, and we are all just on the same team, and we got a chance to say we still exist, got a chance to raise our voices a bit, and maybe somehow it all sinks in.  Of course the calls for us humans are more complex, spanning multiple time zones, cultures, sleep patterns, and emotions.

But it’s a whole perfect universe for the cockatoo, lives for almost ever, moves from tree to tree, calling as it goes, forming and disforming meetings, deciding on the future, then abandoning it for a nice crab apple, making a mess of it, and then moving on.
Photo: Kates Photo Diary with permission

Fixing the ETI 477 100W Audio Amp module

ETI 477 Power Module Circuit Board showing the bipolar transistors heatsink assembly.

Back in 1981 there was a design for a power amp kit, published by Electronics Today International.  The design was a pretty good one, which had very low THD figures and plenty of power.  More interesting to me was the idea that it would use MOSFET output stage instead of Power Transistors, or Valves.  The FET acted more like a valve in anycase, so all was good.  I had built it that same year, but had pretty much only ever used one channel, since I had only one speaker built. [other things to worry about i guess]

Even prior to that in the late ’70s at the University of Sydney I had attended all the graduate lectures of the great Cyril Murray [Electronics] and Richard Small [Audio].  These guys were the total gurus of amplifier and speaker design at the time and were really pushing the envelope in Sydney for how to make very high quality audio equipment – out of the new stuff – transistors – better materials – MOSFETs for example.  So when the ETI design came out, I could see the potential value and have something of the designs I had learnt from Dr Murray built into something I could put together.  Many others probably thought the same.


My son had his 18th birthday recently, and we had aquired two old speakers, so the thought was, lets connect them up and use those for the party.  It was a great idea, except that only one channel actually worked, the one i had used for the past 30 years.  The other channel was just creating lots of hum and noise.  So it was back to the single channel single speaker again.  The whole AMP / SPEAKER arrangement was placed outside in anycase, so it could have been cockroaches, insects, termites or any other kind of small living thing that tends to make its home in strange electronic equipment here.

Then, it was a long weekend, being in honour of the Queen of England, we all Aussies got Monday off work.  It is still raining Tuesday, and a short break over lunch..Looked inside, found about 6 resistors burnt out.  Here was a problem, no circuit diagram, and it took me a while to remember how the whole circuit worked as well.

So David Tilbrook had designed the AMP for the ETI magazine, and since the magazine was now out of date, i searched all over for someone on the web who knew anything about it…. Yes in fact., there were whole threads about this little known amp and its redesign by David Tilbrook, and the subsequent more advanced amplifier, the AEM6000, and if you are interested then join up with DIYAUDIO which is a pretty useful forum.

So this last Saturday, I downloaded the circuit, established which components were broken, went down to the local electronics place and could not believe that I could still buy all of the damaged components off the shelf.  I mean this amp was designed more than 30 years ago boys !.

So… then a day or so of painstaking replacement of burnt out tracks, and burnt out components.

I switched it on.. !@#$!~ heaps of smoke started pouring out of one or two of the resistors.  But since I was watching I saw which resistor was going first.  It was one just connected to a capacitor, a very small feedback capacitor {C14}.  For that much power to burn out a resistor it had to be a shorted cap, never heard of that before.  I checked the resistors, black but still working, transistors should be ok.  Resistor values were out by around 10%.  I only had it on for around 3 seconds.

Replaced the resistors for the second time.

When I replaced the capacitor, a very small one, I noticed that it had been mounted quite close to a straight aluminium heatsink, which has all the bipolar power transistors mounted on it.  It may have been heat stress or something that caused the capacitor to fail.  When I replaced the capacitor, I made sure it was lying down on the PC board, well away from the the high temperature heatsink.  It heat had been the problem for the little capacitor , then it would not be a problem for this little guy in the future.

This time turned it on, it worked, but the sound was not good, it sounded like crossover distortion..

So I carefully poked simple multimeter probes into the high voltage part of the amp, connecting them to either side of the variable resistor RV1, and adjusted the bias on the MOSFET gates to the same as the working channel, about 1.4 volts dc.  It improved dramatically, and since the most sophisticated measuring equipment I have is my ears, and a Herbie Hancock electronic music record, I figured it would be ok.  I then double checked the steady state temperature on the large heatsink, and both channels were operating at around the same temperature [around 40C].

Now both channels sound identical and very clear.

A nice amp, a great designer, and made of useful components, which are still available. The board layout is simple, and there are many small capacitors put in to compensate the amp for parasitic noise and oscillations.  I don’t have any problem with the AMP, It had been built exactly to the instructions in the magazine at the time.  I think though if I wanted to build a new one I would probably built the AEM6000 with whatever other mods various enthusiasts have suggested on DIYAUDIO.

Annotated Circuit Diagram - showing failed capacitor

Lunar Real-Estate – An Earth Facing View

Ferodo was sitting at a side table in the club lounge of the Hyatt Regency hotel in Delhi.  His local Indian colleague and friend Tanish was sitting there across from him.  Scotch this time, it was late, in the evening, dark and monsoon out, it had not been a good day, after three weeks of bad days, the pair had just about had enough.

The desk clerk Anuga, at the lounge dropped by and since there were few people around, and not so busy, asked how they were doing.

Really not so bad, said Ferodo.  We’ve been out, and now we are back.

“So, what brings you to Delhi then ?” asked Anuga

Ferodo said “actually we are… in real estate”, “there is a united nations sponsored conference on here in Delhi at the moment.”

Anuga said “oh really, I hadn’t heard of that one.”

Putting down his glass, Tanish stepped in and added “yes, it is not that well publicized, but my friend here, Ferodo, is a scientist and is helping with some key questions”.

Ferodo looked over at Anuga more intently and said “You see we’re looking into real estate on the moon.” and took a careful sip of scotch.

Anuga looked between both of them, somewhat incredulous, and assumed they were both pulling her leg.

“Yes that’s right”, said Tanish, “you see Ferodo is an astronomer, and so he knows all about the conditions on the moon and is advising the UN and the real-estate brokers all about the situation of housing on the moon. I myself sell real-estate, so I’m selling land on the moon.  Well, not yet though we are still finalizing the details.”

Tanish an ambitious kind of guy, got up and left saying he would be back shortly.

Anuga looked at Ferodo, Ferodo looked at Anuga.

“You see it is like this”. said Ferodo – “there are several key features about the situation of real-estate on the moon, and many misconceptions.  For a start  The moon has a day, almost like the earth’s.  So day and night is not a problem.  The real problem is that it is constantly facing the earth.”

Anuga said “Yes like the man in the moon right ? It always looks the same.”

“Right”, said Ferodo, “It always looks the same, it is always facing the earth, even though the Earth spins past, it is always facing it. ”

“So why is that a problem ?” asked Anuga

“It’s simply a problem for humans, not for the moon. If you were sitting on the earth facing side, you would see the earth.  Always. You could never stop seeing it.  Even when the moon went round the back of the earth at night, you could still see the lights of Taiwan, Japan, UK, not so much India, but you could still see it.”

Ferodo sipped his scotch and gazed out the window as if drawn by a problem too hard to solve.

Anuga said “Really !, I never looked at it that way. But that would be good woudn’t it ?.”

Tanish had rejoined the pair at the table, but had missed the conversation.  Ferodo asked Tanish to explain why a permanent earth facing view was a problem.

Tanish said “You see the real problem is that the earth is always always in the same spot in the moon’s sky.  So if you put a house on the moon, it can only see the earth in a particular position.  So one of the key features is ?”

“An earth facing window !” said Anuga. “Wow, Let me get you another drink and you can tell me more.  I don’t see that is a problem.”

Anuga went off to organise some more drinks.

Ferodo explained to Tanish, “You better tell her about the earth facing side, and the non earth facing side of the moon.”  “Like you cannot sell land on the non-earth facing side, i.e. the dark side, which is not dark, just can’t see the earth.”

Tanish, the ambitious one, said “Not a problem. There must be many people who really don’t want to look at the earth, reminded of the place they left, where their family and ancestors are, where their old long lost friends are.” “Living on the non earth facing side would be perfect for them.”

Ferodo waited.  Anuga returned.

Anuga, looking excited told Ferodo. “i know what the problem is, I figured it out, but I have a solution.  You want to hear it ?”

“OK go on” said Ferodo

Anuga kept her voice low and said quietly “You just need special blinds, you know special blinds that you can close.. and then just open them whenever you feel like looking at the earth, you know, to remind you of home”

Tanish was thinking as was Ferodo, perhaps it would work.  They might each mention it at the conference in the morning.

Michaelangelo’s Teleporter – Leaf 3 Rome and Kaohsiung

Leaf 3…

“Ferodo, look out !” said Alynn, as Ferodo, distracted, lurched across the road.  The car braked, Ferodo saw the car, and the driver in a black leather jacket – finger up – and with his head out of the window yelling in italian as he screamed away.  Ferodo saw the street and the car with extreme clarity and just got himself together when his cellphone rang.  He fumbled all through his coat, and got the phone. Green button ok, “Yes” said Ferodo. “Nin Hao Mr Ferodo” said the voice on the phone. “Someone from Taiwan” said Ferodo, “Taiwan !” said Alynn, “Get off the road” she screamed again.  “OK OK” said Ferodo jumping back on the curb. “Keep it cool”.

As Ferodo got back on the curb, the Taiwanese concierge at the grand hotel Kaosiung was on the phone, to let him know that his limo he had ordered earlier that day had arrived and he should come down to the lobby now.

Suddenly Ferodo found himself not on the curb but in the Hotel in Kaosiung. In his room, no Alynn, no Rome, and on his cell phone to the concierge.  The red light flashing on his room phone.

The fire alarm suddenly went off in the room.  He shut the cellphone, dived for the door, mainly to escape the incessant alarm.  He couldn’t smell any smoke decided on eight flights of stairs rather than the elevator. Started down and ended up in the lobby.

There in the lobby was a mild form of panic, people in pyjamas, t-shirts, suits, and other forms of dress.  All were heading for the lobby doors, themselves opening and closing at random.

Sir, Sir, don’t worry.  False alarm. You wait here a minute.” said a uniformed person with a hat.

It looked dark outside.  Ferodo looked at his watch, he really had no memory now of his short time in Rome.  It was as if he had dreamt it.  Where was Alynn ? . he thought briefly.

He walked out of the lobby, down the stairs onto the main drag of Kaohsiung.  “Forget the limo” he told the concierge as he walked out. “Cancel please”.

It was cold, but he needed to clear his head.  Fading memories of this afternoon and Rome and now a pretend fire in the hotel.  A bit much really.

Not over yet. He walked down the street, and as he wandered down he turned into a deserted street down by the water.  There was no one to be seen, the street was deserted.  It got gradually lighter.  He called into a nearby cafe and ordered a drink.  “Lotus Root” he said. “San Yuan” said the vendor – an attractive girl who smiled at him.  It got dark again.  He walked out into the street.  It got lighter and noisier and he ended up inside a restroom in a restaurant in Rome.  He did have a drink in his hand, but it was not Lotus Root, or flower tea for that matter.  It was a chinotto, in a small bottle.  He was totally alone in the restroom, but then a loud banging on the door, took his attention.. “Ferodo ?” “You in there ?”.. – sounded like Alynn he thought.

This story to be continued, based on the conjunction of the uncertainty principle, so elegantly captured in Ashley’s photograph above, and the contraction of time within the skylight of the church of Angels and Martyrs in Rome.

To be continued from these notes.. CJS