Toroid placement inside enclosure, stray field

remmelt · 11th December 2009, 12:42 PM

I'm trying to build a compact enclosure for my BrianGT 3886 dual mono amp. I'm going the full dual mono route: two toroidals + two PSU boards.

My questions are about the interference the stray field of the toroidals might cause.

1) I hear they're not supposed to be stacked one on top of the other. Is this true? (And why?)

I was thinking about putting the xformers on their sides, with the PSU boards in between.
2) How far apart do they need to be to be considered not stacked?
3) Will the transformers cause interference on the PSU or the amp board? Can I safely put the PSU board on top of or in between the transformers?

I'm going to include a sketch of my current plan. Crappy phone pic of a quick sketch, so bad quality, but you get the idea. The enclosure will be 130mm high (leaves 10mm on each side of the toroids), 185mm wide. Depth to be determined. There is 95mm between the tops of the transformers. The PSU boards are stacked in between, using standoffs. The amp boards are to the back, side by side for better heat dissipation.
The sketch shows the front view.

4) Any reason not to put the transformers on their sides? (Will they sag to the bottom? I could support them with some foam or something)
5) Heat dissipation for the rectifier diodes: would stacking the PSU boards like that cause a problem?

The transformers are Amplimo 2x22V 160VA.

acold7dusta · 16th December 2009, 05:17 PM

1. I wouldn't solely on the fact of the increased difficulty of mounting them, not to mention its bad design practice

3. not sure. In between, yes, but on top of, I would leave a half inch or so of clearance

4. I have seen high end manufacturers mount them upright in the front of the case (next to each other- ~1/2" apart) and I have also seen them mounted flat in the middle, with all boards verticle on each side

5. as long as they're not smothered, I think you'll be fine

11th December 2009, 12:42 PM	#1
remmelt diyAudio Member Join Date: Nov 2009 Location: Amsterdam	Toroid placement inside enclosure, stray field I'm trying to build a compact enclosure for my BrianGT 3886 dual mono amp. I'm going the full dual mono route: two toroidals + two PSU boards. My questions are about the interference the stray field of the toroidals might cause. 1) I hear they're not supposed to be stacked one on top of the other. Is this true? (And why?) I was thinking about putting the xformers on their sides, with the PSU boards in between. 2) How far apart do they need to be to be considered not stacked? 3) Will the transformers cause interference on the PSU or the amp board? Can I safely put the PSU board on top of or in between the transformers? I'm going to include a sketch of my current plan. Crappy phone pic of a quick sketch, so bad quality, but you get the idea. The enclosure will be 130mm high (leaves 10mm on each side of the toroids), 185mm wide. Depth to be determined. There is 95mm between the tops of the transformers. The PSU boards are stacked in between, using standoffs. The amp boards are to the back, side by side for better heat dissipation. The sketch shows the front view. 4) Any reason not to put the transformers on their sides? (Will they sag to the bottom? I could support them with some foam or something) 5) Heat dissipation for the rectifier diodes: would stacking the PSU boards like that cause a problem? The transformers are Amplimo 2x22V 160VA.

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16th December 2009, 05:17 PM	#2
acold7dusta diyAudio Member Join Date: Sep 2009 Location: Buffalo, NY	1. I wouldn't solely on the fact of the increased difficulty of mounting them, not to mention its bad design practice 3. not sure. In between, yes, but on top of, I would leave a half inch or so of clearance 4. I have seen high end manufacturers mount them upright in the front of the case (next to each other- ~1/2" apart) and I have also seen them mounted flat in the middle, with all boards verticle on each side 5. as long as they're not smothered, I think you'll be fine