The ribbon in my first post is 27mm wide and 1050mm long. Magnets are N35 10*10*150mm.
Thanks ABJensen,
I'm trying to find source of that fine Washi paper, should'nt be far off the thickness of the capacitor paper, I think. Otherwise I've got few meters left of DuPont Mylar 3um, but that will not corrugate well.
Would a 6 microns aluminium ribbon with a 2 ohms resistor in series be equivalent? The 12 microns thick paper is probably lighter (factor 1.35 estimated) than 6 microns aluminium ribbon.
With such a wide gap (27 mm) and small magnets with a square section (10x10 mm), the magnetic field is very uneven in the ribbon gap - weak in the middle compared to the magnet surface. But then, if it sounds good ...
Brunob , could you explain your position on this a bit more , the middle will always be weaker than the ends, are you suggesting a different magnet size (instead of 10x10 ) to give more field strength in the middle ..
regards,
What about adding helper magnets in the middle, instead of steel pieces to close the magnetic circuit. You could space them out to
compensate for weaker field in the middle and no problems with saturation point of steel. Also use stacked disc or rod magnets to
minimise reflections from the back.
Peter.
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What software are you using to measure?
This build is very similar to my ribbon prototype that I built a few weeks ago.
I will redo the ribbon with supports spaced along the ribbon as it tends to move out of the magnetic field. Also I will build a more "domestic" construction in a wife-acceptable design and colour when the time comes.
regards,
Bent
This build is very similar to my ribbon prototype that I built a few weeks ago.
I will redo the ribbon with supports spaced along the ribbon as it tends to move out of the magnetic field. Also I will build a more "domestic" construction in a wife-acceptable design and colour when the time comes.
regards,
Bent
I havent measuret them yet. But will use the software for my DSN28 pre Ground Sound . And Holm freeware.
And yes mine is very smilar, they will probably almost measure identical.
I will probably have too put some spacers one mine too. This super thin aluminium gives very little spring effect.
And yes mine is very smilar, they will probably almost measure identical.
I will probably have too put some spacers one mine too. This super thin aluminium gives very little spring effect.
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I performed several FEMM simulations and measurements. Narrower magnets and deeper cavities give a more homogenous magnetic field in the gap.
See "The tall neodymium ribbon". Part 1. See also http://www.diyaudio.com/forums/plan...d-constructing-ribbon-unit-2.html#post2466928
Just got some alu leaf tape this morning. Wow, 25 cm length of 45mm wide tape measured 1.2R. I'll be replacing the ribbon over the weekend on my 1.3 m ribbons 
. Quick test of corrugating the ribbon bonded to 3um Mylar worked a treat, thanks ABJensen, great idea. Btw was your aluminium leaf tape made up of small sections or was it continuous length? That might be the reason for higher resistance (apart from thickness) since there will be contact resistance between the small pieces that make up the tape.
Peter
. Quick test of corrugating the ribbon bonded to 3um Mylar worked a treat, thanks ABJensen, great idea. Btw was your aluminium leaf tape made up of small sections or was it continuous length? That might be the reason for higher resistance (apart from thickness) since there will be contact resistance between the small pieces that make up the tape.Peter
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Just got some alu leaf tape this morning. Wow, 25 cm length of 45mm wide tape measured 1.2R. I'll be replacing the ribbon over the weekend on my 1.3 m ribbons
Peter
Now does the increased resistance comes at a cost in sonics ...?
wider magnets are much stronger
but only makes sense if you place them like this
ribbon is placed in level with front of magnet
felt between the magnets
very easy to build it like this
no need to use glue on magnets either
Attachments
I have made a short ribbon 60cm*2.2cm like that with doppel layer of magnets.
It works quite well.
Hi Jer,
Used spray adhesive but it's way to thick, I'll have to get some 3M stuff.
Peter
Mine is made of 15cm leaf that overlap. Is yours continuous ? UKPD.Looking forward too your opinion of the sound.Well I am happy too bring some too diy comunity. Just call it the Jensen ribbon
Mine are with 10 cm leaf which is very loose on joints, when rechecked previous measurement pressing at the joint lines the resistance was dropping.
I will try to press the ribbon while gluing & see if that helps. Maybe put some thinned down silver conducting adhesive on the joint.
Jensen ribbon... like it
Cheers
Peter
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