Anyone know where I can get a single custom toroidal made?

SQLGuy · 25th December 2009, 11:46 AM

Hi folks,

I've got a REL Stampede sub that I brought back to the US. Unfortunately, these had 230V non-restrappable power supplies. I've been using it with an external step-up, but I'd prefer to replace its main transformer with a 115/230 dual-primary one. Since the unit was never offered in a 115V version, I can't get a correct transformer from REL.

The transformer is 150VA or so, and has 2x 35VAC and 2x 15VAC secondaries (IIRC). I'd like to send it out somewhere to either be rewound with the dual primaries, or to be used a guide for a custom-made one-off replacement. I emailed Plitron to inquire about this a few weeks ago, but never received a reply. Any other suggestions on who might be able to do this?

Thanks,
Paul

Magura · 25th December 2009, 11:51 AM

The easy solution is to get an 230-115 transformer, and put it in front of the sub.
Such can be had off the shelf for cheap.

Magura

pooge · 25th December 2009, 01:09 PM

SumR - Richard Sumner Technology:: Primrose

poynton · 25th December 2009, 01:50 PM

or buy 2 transformers, one @35vac and one @15vac

both available off the shelf

Andy

.

SQLGuy · 25th December 2009, 03:53 PM

As mentioned, I am already using the "easy solution". Which is fine except for the constant buzzing of the 115 to 230 step-up. It's also, IMO, inelegant.

Getting two transformers, as Poynton suggested, is not a good option, as it will significantly change the open volume of the sub cabinet, even assuming I could find two suitable transformers.

Thanks Pooge, I'll check with them.

Cheers,
Paul

jaycee · 26th December 2009, 12:36 PM

You could also simplify things by buying an off the shelf 2x35V 160VA unit, and then building some pre-regs to step the main rails down a bit before feeding them into the regulators that ran from the 2x15V winding. The only penalty here would be extra heat from the pre-regs.

SQLGuy · 26th December 2009, 08:22 PM

That's an interesting idea. I'll check into it too.

jaycee · 26th December 2009, 08:48 PM

Rod Elliot has a good article already:

Pre-Regulator

This is exactly what you need. If you use 20V zener diodes, then the supply produced should feed the original regulators perfectly. They are most likely 7*12 or 7*15 anyway!

elac310 · 30th December 2009, 12:10 AM

TRANSTEC in Germany would certainly do the job; excellent quality toroids and helpful people who don't send someone to hell because s/he orders only one transformer; see TRANSTEC GmbH - Hersteller von Ringkern-Transformatoren (ENG page available)

I'm sure there are plenty of, if not more, excellent winders in the US as well. But just in case...you can count on this one at least.

Chris.

jackinnj · 30th December 2009, 01:00 AM

Why not rewind the original? The 35VAC secondaries will give you around 16VAC. Build yourself a shuttle and you can unwind the secondaries. You can get the appropriate magnet wire on EBay, or from www.amidoncorp.com It's not rocket science.

25th December 2009, 11:46 AM	#1
SQLGuy diyAudio Member Join Date: Jan 2009	Anyone know where I can get a single custom toroidal made? Hi folks, I've got a REL Stampede sub that I brought back to the US. Unfortunately, these had 230V non-restrappable power supplies. I've been using it with an external step-up, but I'd prefer to replace its main transformer with a 115/230 dual-primary one. Since the unit was never offered in a 115V version, I can't get a correct transformer from REL. The transformer is 150VA or so, and has 2x 35VAC and 2x 15VAC secondaries (IIRC). I'd like to send it out somewhere to either be rewound with the dual primaries, or to be used a guide for a custom-made one-off replacement. I emailed Plitron to inquire about this a few weeks ago, but never received a reply. Any other suggestions on who might be able to do this? Thanks, Paul

25th December 2009, 11:51 AM	#2
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	The easy solution is to get an 230-115 transformer, and put it in front of the sub. Such can be had off the shelf for cheap. Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

25th December 2009, 01:50 PM	#4
poynton Magneto the Gravity Man diyAudio Member Join Date: Mar 2005 Location: A life on the ocean waves when I'm not at home in N. Wales (but I'm not Welsh so no sheep jokes!)	or buy 2 transformers, one @35vac and one @15vac both available off the shelf Andy . __________________ If it ain't broke, break it !! Then fix it again. It's called DIY !

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25th December 2009, 01:09 PM	#3
pooge diyAudio Member Join Date: May 2003 Location: Northern Va.	SumR - Richard Sumner Technology:: Primrose

25th December 2009, 03:53 PM	#5
SQLGuy diyAudio Member Join Date: Jan 2009	As mentioned, I am already using the "easy solution". Which is fine except for the constant buzzing of the 115 to 230 step-up. It's also, IMO, inelegant. Getting two transformers, as Poynton suggested, is not a good option, as it will significantly change the open volume of the sub cabinet, even assuming I could find two suitable transformers. Thanks Pooge, I'll check with them. Cheers, Paul

26th December 2009, 12:36 PM	#6
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	You could also simplify things by buying an off the shelf 2x35V 160VA unit, and then building some pre-regs to step the main rails down a bit before feeding them into the regulators that ran from the 2x15V winding. The only penalty here would be extra heat from the pre-regs.

26th December 2009, 08:22 PM	#7
SQLGuy diyAudio Member Join Date: Jan 2009	That's an interesting idea. I'll check into it too.

26th December 2009, 08:48 PM	#8
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Rod Elliot has a good article already: Pre-Regulator This is exactly what you need. If you use 20V zener diodes, then the supply produced should feed the original regulators perfectly. They are most likely 712 or 715 anyway!

30th December 2009, 12:10 AM	#9
elac310 diyAudio Member Join Date: Nov 2007 Location: Strasbourg	TRANSTEC in Germany would certainly do the job; excellent quality toroids and helpful people who don't send someone to hell because s/he orders only one transformer; see TRANSTEC GmbH - Hersteller von Ringkern-Transformatoren (ENG page available) I'm sure there are plenty of, if not more, excellent winders in the US as well. But just in case...you can count on this one at least. Chris.

30th December 2009, 01:00 AM	#10
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	Why not rewind the original? The 35VAC secondaries will give you around 16VAC. Build yourself a shuttle and you can unwind the secondaries. You can get the appropriate magnet wire on EBay, or from www.amidoncorp.com It's not rocket science.

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