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Brian

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Posts posted by Brian

  1. 1 hour ago, KevinE said:

     

    The fault can be seen on the PFL 'L' bus that serves the modules. 

     

     

    Aren't they meant to be virtual earth busses? That you can see something on them means a poke around the input to the PFL stage might be instructive.

  2. If you go along to the speakerplans forum and then the amplifier sub forum you will find a post called internals 2. Inside are teardowns of most amplifiers. Always worth looking. 

  3. Asking for a friend who is a tutor at a Uni running live event courses...

    Quote

    I am looking into how practical courses are dealing with the accessibility of kit. At the moment, we have a 24h in advance rule, so no-one can come and get a mic or whatever they need as they need it.

    And I am facing answers that that is the norm, but I don't believe that other universities do not have the flexibility that we don't

     

    Any replies would be very gratefully received.

  4. For proper low smoke you need something like this...

    Le_Maitre_Freezefog_Pro_1.jpg

    You sit a powerful smoke machine, like a Le Maitre G300, behind it, and connect up a bottle of CO2 which has a dip tube output so that you get liquid CO2 out and not gas. The two interconnect and when you operate it you open the CO2 flow first and then the smoke. We normally use LK sized cylinders (95kg total weight) so that we don't have to worry about run time. They are noisy though.

     

    This is what two Freezefog units will achieve in the Royal Albert Hall. The machines are sited downstairs, because they are noisy, and feed to the arena floor through 15m of ducting.

     

     

    Remembrance.jpg

     

    I'd reckon that one unit placed USC would fill you stage quite nicely.

  5. For Dry Ice you need something like this...

    peasouper1446.png?itok=eQG0mcdZ

    It's a large tank of boiling water which you lower a basket of dry ice pellets into. So that's two hazards right off. Plus the stage around the unit gets covered in water. And for continuous use you need more than one machine in every location because they go off the boil really quickly.

  6. On the whole I've been well catered for by the likes of Eat To The Beat. But that just makes the bad ones stand out.

    Earlier this year a job at the Albert Hall. 7am call time so we could get trusses out of the way. Got that rigged so head down to crew catering for breakfast. No breakfast :(. Luckily my rucksack carries long-life calories.

    Crack on till lunch time. Down to catering. Sandwiches. Just sandwiches, no soup, no crisps, just sandwiches which had been made the day before and were starting to develop distinct curves.

    Crack on till dinner time. Down to catering. At least there's hot food. A chicken 'thing' for the meat eaters and something veggie for the rest of us. It was stuffed aubergine or, in other words, bits of leather with wet mush loosely attached to one side with some cous cous swimming in a watery tomato sauce.

    Luckily I know where the IC food shop is so I rescued myself with something edible.

     

    Oh, and that's the gig where I caught Covid.

     

    Thanks Classic FM, you bunch of cheapskates. 

    • Funny 2
  7. 1 hour ago, sunray said:

    My apologies, I'd been posting on a similar subject on another site where we'd been discussing resistor values and confused the 2 threads, so didn't realise you haven' got this far. The pic is typical of the circuit used:

    G143aCompED.jpg

    A google search will throw up loads of ideas/solutions.

    That's exactly the circuit I doodled out.

    If you find the mic overloads the pack then a resistor between the capacitor -ve and the input to the pack will attenuate the signal BUT the value will depend on the input of the pack so it'll be trial and error, but start with 10k.

  8. Don't get too hung up on impedance matching, the beltpack manufacturers don't!

    When John (boatman) and I designed Bluecomm I reverse engineered just about every beltpack out there. All of them have a resistor strapped across the mic input, mostly to keep the input DC operating point stable, and those resistors vary between 3k3 and 47k. So no attempt6 to match 200R.

    The ONLY times impedance matching is important is...

    a) when you need maximum POWER transfer across an interface

    b) when you need to avoid reflections and are terminating a transmission line

    In audio work we are ALWAYS concerned with maximising VOLTAGE transfer, which means have a load impedance much higher than the source impedance.

    • Upvote 1
  9. 18 hours ago, sunray said:

    Thank you for the offer, If you were to offer me diarrhoea tablets would it occur to you to ask if I were on blood thinning medication or antibiotics?

     

    Of course not, if you choose to take them then that's your lookout.

    We're not talking prescription drugs here, we're not even talking over-the-counter, we are talking about things that can be bought in any supermarket, corner shop, or petrol station. Yes they come with a PIL but how many people read those? You can be very sure that, in deciding to make them widely available, the risk of people not reading the information has been considered and found to be so low as to not be an issue.

     

  10. Tell you what. If you ever find yourself working on the same event as me, and need some medication, come and find me. You can have whatever you want, no questions asked. Pain killers, rehydration, wound cleanse, diarrhoea tablets, I've got the lot.

    Am I worried about being sued? Clearly not. 

    • Like 1
  11. 39 minutes ago, John_P said:

    A couple of questions - how much dust and mess do they leave behind? 

    Lots. And it's very abrasive. If it gets onto an LED dance floor or any shiny smooth floor surface, and people then dance on it, the floor will look like it's been attacked with sandpaper.

    As for safety, you really don't want to be getting either the 'lit' particles, or the fallout, into your eyes. Think sand.

    And, as Jon says, they are noisy. Think small vacuum cleaner.

  12. It's going to take me a while to get this lot fully catalogued and photographed but in the meantime, if anyone is interested in making an offer, I have the following to get rid of...

    10 pcs CCT Minuette Fresnels, complete with colour frame and barn doors, hook clamp, 15A plug and safety.

    8 pcs ETC Source Four Profiles, complete with colour frame, hook clamp, 15A plug and safety.

    12 pcs 500W Cyc lights, complete with colour frame, barn doors, hook clamp, 15A plug and safety.

    2 pcs 10m Socapex

    2 pcs Scopex Rail Boxes, 15A

    2 pcs Socapex Rail Boxes, 16A

    ? Pcs Socapex spiders

    I would prefer to sell in batches rather than single units where possible.

    Open to sensible offers.

    I've also got random spares, including lamps, for much of the above which anyone taking a reasonable amount can have.

    Prefer collection from Ely, Cambridge, area.

    There will be more to come including Betapack 2s, pinspots, mirror balls, rotators, 2k follow spots with colour magazines.

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