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DIY Stompboxes => Building your own stompbox => Topic started by: smallbearelec on July 01, 2004, 01:13:51 AM

Title: Small Bear's Flat-Pack Transformers Are In!
Post by: smallbearelec on July 01, 2004, 01:13:51 AM
If you have been discouraged from building GOOD, powerful pedalboard supplies by the high cost of the Magnetek FP12-200 ($10.76 at Mouser), try one of my clones:

http://www.smallbearelec.com/Ordering/Xfmr.jpg

At $5.50, I hope these get your juices going!

Regards
Steve D
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: Peter Snowberg on July 01, 2004, 01:24:25 AM
8)  8)  8)  8)  8)  8)  8)  8)  8)  8)

What's the quantity break and at how many units?

Thanks and congratulations. :D

Take care,
-Peter
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: Lonestarjohnny on July 01, 2004, 01:29:04 AM
cool, have you got  the spec's listed on your site Steve ?
JD
Title: Bulk Pricing and Specs
Post by: smallbearelec on July 01, 2004, 09:06:07 AM
OK--

10 @ $5.00
25 @ $4.75
50 @ $4.50
100 @ $4.25

I have posted a scan of the spec sheet here:

http://www.smallbearelec.com/Ordering/Xfmrspec.gif
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: Ed Rembold on July 01, 2004, 11:40:41 AM
Steve,

Correct me if I'm wrong, but.... I don't think that's enough transformer, I mean, don't you want to use the secondary windings individually (to have 2 outputs)?

Looks like the FP12-200 is only 6.3v (but that's rated at 400ma both windings in parallel, individually it would be 200ma output, maybe the voltage is high enough at say-50/100 ma load ?)

I dunno, could be OK, but too small I think.
Ed R.
Title: Power Supplies
Post by: smallbearelec on July 01, 2004, 03:31:23 PM
Hi Ed--

I guess it depends on how much someone wants to have an individual transformer/output for each pedal ($$$ no matter what transformer).  If you wire the outputs in series, you have 200 ma. at 9 volts to run into a power chain. I think a Small Wart based on this unit will satisfy a lot of needs for not much money.
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: RDV on July 01, 2004, 04:23:42 PM
My PSA-120 somehow mysteriously died between the last note I played Saturday night and yesterday when I plugged it in to try to test a circuit. So I may be ordering a couple and making me a monster supply.

RDV
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: Paul Marossy on July 01, 2004, 05:36:20 PM
RDV,

I'm not totally sure, but I think that PSA-120 might have an internal fuse...
I have one of those, too. I have never tried to look inside of it, but it will come apart rather easily, at least mine is constructed that way.
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: Ed Rembold on July 02, 2004, 01:48:49 AM
Yeah Steve,

You are right, if you do 1 output per transformer, it's plenty.

I guess I had in mind the 4 output, 2 transformer, design that Scott Swartz posted quite a while back.

Thanks, Ed R.
Title: Multiple Outputs
Post by: smallbearelec on July 02, 2004, 10:47:16 AM
Ed--

I kinda guessed that that's what you were thinking. The same factory that made these would do a 60-65 ma. version, and it's something i can put on the shopping list for when I have the capital. For now, I gotta pay bills and save money for taxes (grrrrrr...)

SD
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: RDV on July 02, 2004, 12:14:38 PM
Quote from: Paul MarossyRDV,
I'm not totally sure, but I think that PSA-120 might have an internal fuse...
I have one of those, too. I have never tried to look inside of it, but it will come apart rather easily, at least mine is constructed that way.
It was the classic 'wire broken where it goes in'. I've been through this drill before, so I fixed it by cutting off a few inches of wire and resoldering it back to the board.

Thanks

RDV
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: Paul Marossy on July 02, 2004, 06:14:02 PM
Oh, cool.  8)

But, is there a fuse inside of it? I have always wondered if there is or not. I have never taken min apart...
Title: Small Bear's Flat-Pack Transformers Are In!
Post by: RDV on July 02, 2004, 06:17:35 PM
Quote from: Paul MarossyOh, cool.  8)

But, is there a fuse inside of it? I have always wondered if there is or not. I have never taken min apart...
No. There are 4 diodes, two caps, transformer, & a voltage regulator in mine.

RDV
Title: Transformer pins
Post by: jsleep on July 21, 2004, 03:14:26 PM
I got a couple of these and there's no markings for primary, does anyone know the pinout for this thing?!?!?!


AAARRGGG!

JD Sleep
Title: Re: Transformer pins
Post by: Peter Snowberg on July 21, 2004, 06:50:32 PM
Quote from: jsleepI got a couple of these and there's no markings for primary, does anyone know the pinout for this thing?!?!?!


AAARRGGG!

JD Sleep
The spec sheet (http://www.smallbearelec.com/Ordering/Xfmrspec.gif) gives a pinout and a magnetic polarity of each of the windings, but it doesn't say which side is which.

Luckily, you can easily determine that with an ohm meter. Measure the DC resistance of pins 1 & 2 and then of pins 5 & 6. The higher resistance will be the 115V coil.

I'm assuming that 1&2 and 3&4 are the two 115V coils so with those numbers in mind. wiring up the primary for 115V would involve connecting pins 1+4 and pins 2+3 to the AC input. For 230V primaries it would be AC input to pins 1 and 3 and a jumper between pins 2 and 4. The secondary would be pins 5+8 and pins 6+7 for 6V or pins 5 and 7 as the outputs with pins 6 and 8 jumpered for 12V.

Again, that's assuming pins 1-4 are the primary. I don't have one to play with in person. ;)

Good luck!
-Peter