Salad Bowl Speakers

Dedicated to those large boxes at one end of the room
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Paul Barker
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#76 Re: Salad Bowl Speakers

Post by Paul Barker »

Im only up because someone in Scarborouh started world war III. I feel sorry for the animals I hate people who make loud bangs every opportunity it seems these days. I dont know how Nick and Kay cope. It should be made illegal imho.

I havent said happy new year to anyone either, or bought a christmas present either neither has Diana. We have bigger fish to fry. But all the presents the children and her sister bought she keeps thanking me for having bought. Sometimes demtia works in youre favour. Not often though.

I come from geordie blood, coal first footing and all that from my childhood. All over now, taken over by people who ruin lives with imitation rocket launchers as used in Kieve. Whats the attraction to 8mitating war ffs.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Ray P
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#77 Re: Salad Bowl Speakers

Post by Ray P »

Mike H wrote: Mon Jan 01, 2024 12:38 am You have a sofa in your spare room? :shock:
Yep, it's something of a man cave with a large screen TV, workdesk/PC, etc. plus, unfortunately, an awful lot of clutter - could be New Year resolution there...
Last edited by Ray P on Mon Jan 01, 2024 6:57 am, edited 1 time in total.
Sorry, I couldn't resist!
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Ray P
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#78 Re: Salad Bowl Speakers

Post by Ray P »

Paul Barker wrote: Mon Jan 01, 2024 2:31 am Im only up because someone in Scarborouh started world war III.
I hope you are feeling better this morning Paul, having had some restful sleep after the ceasefire took affect? Happy new year mate and look after both of you as best you can...

On a happier note, last evening I stumbled on the article I wrote for HiFi World back in 2003, documenting my Bottlehead paraglow build, that led to my attending VSAC 2003 with you and Clive - where have those 20yrs gone!
Sorry, I couldn't resist!
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Greg
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#79 Re: Salad Bowl Speakers

Post by Greg »

An example of custom built 3D printed stands.

Image
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Ray P
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#80 Re: Salad Bowl Speakers

Post by Ray P »

Greg wrote: Fri Jan 05, 2024 6:37 pm An example of custom built 3D printed stands.
Cheers Greg, another idea to ponder.
Sorry, I couldn't resist!
Morgan Jones
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#81 Re: Salad Bowl Speakers

Post by Morgan Jones »

I've just ordered four 28cm Blanda serving bowls from Ikea. Obviously, with all my other unfinished projects, what I really need is another. But I've had a pair of JX92S sitting in their boxes for a very long time.
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Paul Barker
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#82 Re: Salad Bowl Speakers

Post by Paul Barker »

I know what you mean I just draw new projects on paper, order the parts and change my mind.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
steve s
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#83 Re: Salad Bowl Speakers

Post by steve s »

I think that's normal around here, I have loads of projects in limbo
Best of luck morgan with those..
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Morgan Jones
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#84 Re: Salad Bowl Speakers

Post by Morgan Jones »

But, but, I've finished a project, so that proves that things get done. Eventually.

What you see is a pair of Helmholtz coils lovingly crafted from finest offcutium (and 3.7kg of 0.67mm enamelled copper wire). Each coil has 720 turns and their separation is equal to coil radius. The coils are 270mm diameter at the outside of the winding. Within a central sphere of about 88mm diameter flux density is constant to within 1%. But what is the flux density? With the arrival of better compass this morning, today's job was to calibrate the coils. I rotated the coils until the compass needle was aligned with the plane of the coils and with 0 degrees on its scale. I then applied a direct current from a power supply and twiddled it until I got 45 degrees deflection, indicating that the field I was producing was equal to the Earth's field, but at a right angle. That all sounds easy, but it was quite fiddly. Playing cards were used to get everything level. Reversing the current helped iron out zeroing errors on the compass, and tapping the compass helped achieve repeatable readings. Oh, and it was a big undamped compass with 1 degree graduations that the needle almost touched. I read the scale wearing Optivisor 3 to be able to really see what was going on. The result? Theory says I should see 5.28uT per mA of current. Measurement gave 5.27uT per mA. I am well pleased. (If you want to look the technique up, search for "tangent galvanometer".)

Oh? You want to know what it's for? If I drive the coils with 50Hz from a signal generator and know the current (which I can measure quite easily), I can determine how susceptible a cartridge or small transformer is to a known hum field. Further, I can calibrate search coils against the Helmholtz coils, enabling me to wave a search coil at flux leaking from a mains transformer or motor and know what the leakage flux is.

My salad bowls are due to arrive on Saturday.
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Morgan Jones
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#85 Re: Salad Bowl Speakers

Post by Morgan Jones »

Salad bowls arrived. One now has a 112mm diameter hole in the end, plus a 140mm diameter rebate 4mm deep. Just tested; JX92S fits snugly. The Cock-up Fairy is probably out on her rounds now, so I'll do the second hole and rebate tomorrow. There's not a lot of meat inside for the screws to engage upon - I may add some blocks behind to strengthen everything. Or perhaps a plywood ring.
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