Jump to content

Craig Sawyers

High Rollers
 View Profile  See their activity

  • Posts

    5,304

  • Joined

  • Last visited

  • Days Won

    30

 Content Type 

Posts posted by Craig Sawyers

  1. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted · Edited by Craig Sawyers

    Regarding transistor mounting. I'm thinking back a looong time to when I built mine. I used steel screws, because I could not get enough torque on plastic screws (I use a torque screwdriver and read the data here https://www.onsemi.com/pub/Collateral/AN1040-D.PDF ).

    But the trick is to use the AAVID long penetration washers.

    You need enough length to go through the TO220 tab, and penetrate most of the way through the 4171G insulator.

    Now the problem is that the thickness of the tab is extremely widely specified - somewhere between 0.5mm and 1.39mm. I've done a straw poll of TO220 devices I have, and the vast majority are between 1.25mm and 1.3mm thick. My 4171G insulators are actually 2mm thick (at the top end of the tolerance; they are nominally 1.778mm (0.07") +/- 0.254mm (0.1"). So mine are towards the top end of the tolerance band.

    Anyhow, it looks like the AAVID 7721-13NG (Mouser has 8,000 of them) is the man for the job. I can't find the remainder of the ones I bought to check, but I think I used those. The extension is between 2.71mm and 3.26mm. You need to check your tab and insulator dimensions, but under most circumstances the shoulder washer will go through the TO220 tab and most of the way through the 4171G.

    If the tolerance stack goes against you, that shoulder washer might actually protrude from the bottom of the 4171G. If that is the case you absolutely must trim the end shorter. Otherwise you won't make thermal contact between the transistor and the heatsink.

    That will enable you to use steel screws and nuts (don't forget the lockwasher!).

    Oh - and you absolutely must use heatsink compound!

    Craig

    • Thanks 1

  2. Dyson Zones

    in Headphones

    Posted

    I never thought this ridiculous product would see the light of day. What an awful concept.

    But Dyson have had much more serious products bomb. They developed a washing machine. Normally washing machines have a big block of concrete in the back to stop the spin cycle from making the machine jump around and shake itself to bits. Which is why washing machines are stupidly heavy. Dyson came up with a contra rotating drum and active stabilization. A superb idea - much lighter weight, quiet (because Dyson understand motors) - and so punishingly expensive that very few bought it.

    Let's not forget that James Dyson's first product was the Ball Barrow - the usual wheel on a wheel barrow was replaced by a ball - so you could turn corners more easily. Of course lots of companies make them now because Dysons' patent on this is long expired. But typical of the man - he took the concept of a ball on an axle to boat launching and other marine activities.

    But the product that came to define him was the cyclone vacuum cleaner. Developed in his back room of his modest house. Then Hoover took his patent, copied it and started making them. Dyson fought back, and won with massive punitive damages.

    But the reviews have it right for the daft headphone/filter thing. All Dyson's current products are to do with motor technology and filtration, and excellent product form and feel. And this massive headphone construct with the mask is no exception. For all its weight and laughable appearance, it is superbly designed and built.

     

     

    • Like 1

  3. RIP someone or another

    in Off Topic

    Posted

    On 5/25/2023 at 12:03 AM, TMoney said:

    RIP to the queen of Rock. What an amazing life and an amazing talent. To have escaped from that monster and had the late career rebirth in the 80s was just so impressive.

    This made me think of

    Image

    • Like 6

  4. And now what did you do TODAY?

    in Off Topic

    Posted · Edited by Craig Sawyers

    Actually two days ago. Went to see a play at Chichester, in the tiny Minerva theatre https://www.preevue.com/projects/minerva-theatre . The play was called 4000 miles, and we really went to see it because it has Eileen Atkins in it. A titan of theatre and movies.

    She was splendid, but looked a bit old (the character was of an old woman).

    It was only when we got home and checked: 88. Still treading the boards at 88! Hell she started as a professional leading actor in 1953 -  three years before I was born.

    This is she - courtesy of Wikipedia  https://en.wikipedia.org/wiki/Eileen_Atkins

    • Like 8

  13. The Knuckledragger 3rd Memorial Slow Forum Post

    in Off Topic

    Posted · Edited by Craig Sawyers

    You have no idea what we have had to put up with in the UK on this. It has been pretty much saturation on radio and TV for a good week before the coronation. By the way, there is a war raging in Ukraine and Sudan - 10 seconds - but what about the coronation chaps!

    BBC1, BBC2 and ITV showed it simultaneously, and if you missed a bit it was available on +1 and on streamed catch up.

    My daughter and her husband watched it in Australia, but they didn't get a week of preamble, so they were less jaded by the whole thing.

    Turned on in the evening, and a bit like football pundits there was a post coronation analysis running.

  14. RIP someone or another

    in Off Topic

    Posted

    Same thing happened to Dave Swarbrick, violin player and singer in Fairport Convention. He used to make a joke of it and announce his demise before a concert, handing out signed copies of his obituary.

    https://en.wikipedia.org/wiki/Dave_Swarbrick

    He ultimately did die aged 75. As a lifelong chain smoker, he had shot lungs, and after three tracheostomies used to perform with an oxygen cylinder and mask next to him that he had to puff on during a gig. He was a seriously determined performer.

    He needed a lung transplant to save his life, but our health service wanted nothing to do with him and a private operation was the only way. So the folk singing community held a series of concerts called SwarbAid to raise money for the treatment. That bought him 10 years, during which I saw him in a tiny folk venue with Martin Carthy a a year before Swarb actually did die.

    https://en.wikipedia.org/wiki/Martin_Carthy

    • Like 4

  18. What TV show are you watching now?

    in TV

    Posted

    Second season of Happy Valley is better, and the final season is totally awesome.

    Only 6 shows per season - so 18 in all. Sarah Lancashire is one of the best actors around. The writer Sally Wainwright specifically wrote the script with Lancashire in mind as the lead character.

  20. The Knuckledragger 3rd Memorial Slow Forum Post

    in Off Topic

    Posted

    That octopus did not just do it once. Each morning there was an aquarium power outage and the 2,000W spot was blown. After a number of days, they staked out the tank at night and caught Otto blowing the lamp with a squirt of water. He also juggled with hermit crabs and rearranged his tank to suit his taste.

    A very strange lifeform with a distributed brain - 2/3 of which are in the arms. It has as many neurons as a dog. Hence the creature's smartness.

    I really don't have a problem with beef, pork, lamb or chicken. It is my view that these animals have done very well in terms of population by the fact we eat them. But I'm now unhappy about eating octopus, delicious though it may be - in raw intelligence it is similar to eating a dog.

    Deliciousness was the reason the dodo became extinct. The flightless and friendly bird was just too darned superb to eat. So sailors just ate all of them.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.

  I accept