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Who wants +/-15 and +5 triple secondary toroids?


Doug Wellington

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I'm looking into a batch of custom wound toroidal transformers for the MB-808 project - they'll have dual 15V secondaries to provide +/-15V for the analog section PLUS a 5V winding to be used for the digital section.  That way, we won't have to chain a 5V regulator after the 15V section, and it should be fine for devices that require +/-12V and +5V too...

So far, the minimum quantities for custom windings are large (500x) or expensive ($50), so I'm hoping that I can drum up enough interest to go for the quantity and get them at a better price.  Here's the group buy sign up link:

http://www.midibox.org/dokuwiki/dougwellington_transformer_bulk_order

EDIT: the info is on the wiki page, but just to clarify, there are dual inputs to handle both 110V and 220V....

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I'd probably be interested :)

any more details also on the Ampere rating etc? I guess for bigger projects like what I'd use them for, at least 1A on the 15V and 1.5A on the "5V" would be cool.

for the 5V rail, a transformer voltage of 7.5V would be perfect.

S

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any more details also on the Ampere rating etc? I guess for bigger projects like what I'd use them for, at least 1A on the 15V and 1.5A on the "5V" would be cool.

for the 5V rail, a transformer voltage of 7.5V would be perfect.

May I suggest 2-3A and 8V? I'm thinking about lots of LEDs...

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OK, well, without getting into the whole Root Mean Square thing...  ;)

The idea is to be able to provide enough power to work with the regulators we're using in the MB-808 - 2A for 5V and 15V and 1.5A for -15V.  For reference:

[table]

[tr][td]

+5V

[/td][td]L78S05CV[/td][td]http://www.st.com/stonline/books/pdf/docs/2148.pdf[/td][/tr]

[tr][td]

+15V

[/td][td]L78S15CV[/td][td]http://www.st.com/stonline/books/pdf/docs/2148.pdf[/td][/tr]

[tr][td]

-15V

[/td][td]L795CV[/td][td]http://www.st.com/stonline/books/pdf/docs/2149.pdf[/td][/tr]

[/table]

I'm also planning to put together a standard power supply circuit board that I can put in my various projects.  Stay tuned for another group buy!  ;D

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I don't have an exact weight yet, but I think it will be about 450g.  I'll be happy to ship anywhere...

thought it to be heavier... if it's under 1-2kg that's perfect i'd say, not less  ;)

recently got custom +/-18v transformer for klee, weight shows about 1.5-2kg i guess

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I recently found these (http://www.toroid.com/standard_transformers/rectifier_transformers/rectifier_transformers_mult.htm)and ordered one for my midiboxFM project. Unfortunately, work has gotten really busy since then and I haven't had a chance to try it out yet, but I think it's going to work. It was expensive but it is really nice quality and they shipped fast.

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I'm probably interested in a couple if the price and postage is right. I've put my name on the list to show an interest but would need to know the price (postage) before I commit.

I'd also appreciate some advice on how to wire them up because I'm scared of have respect for mains electricity.

          G

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I'm probably interested in a couple if the price and postage is right. I've put my name on the list to show an interest but would need to know the price (postage) before I commit.

I'd also appreciate some advice on how to wire them up because I'm scared of have respect for mains electricity.

Same to all,

Asaf

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sorry to hi-jack, but if i were to use this for the MBFM project, would i just not use a V-reg on the core since this trafo already puts out +5v?  i assume +/_ 15V is just fine for the OPL3 module etc...  just curious about the +5V rail.

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sorry to hi-jack, but if i were to use this for the MBFM project, would i just not use a V-reg on the core since this trafo already puts out +5v?  i assume +/_ 15V is just fine for the OPL3 module etc...  just curious about the +5V rail.

the xformer outputs 5vac, you still need to rectify and regulate it...

i'm not sure the opl can take +-15v, but current draw is low enough you should be ok with feeding 12v regs from this xformer...

btw, doug, i have had issues w/ using a 7vdc wallwart on the midibox core, which is what you should get from 5vac * 1.414

if it is rated at a higher current than you pull, it could be ok, but it is cutting it a bit fine for the usual 7805...

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just had a re think.while the secondaries sound all good ignoring R.M.S. for the moment. Question for doug you didn't specify voltage supply for the primary

since you are in the US you would of course be looking at 110V which wouldn't suit a lot of people in other countries , or are you already ahead of me and

specifing two primary windings into the design as they are to be custom wound ?

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just had a re think.while the secondaries sound all good ignoring R.M.S. for the moment. Question for doug you didn't specify voltage supply for the primary

since you are in the US you would of course be looking at 110V which wouldn't suit a lot of people in other countries , or are you already ahead of me and

specifing two primary windings into the design as they are to be custom wound ?

*SLAP*

The proposal is to buy a fairly large quantity of Toroids with not just 110/220V inputs with dual 15V secondaries, but to add in a third set of secondary windings for 5V

*/SLAP*

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  • 3 weeks later...

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