Sony vFET Illustrated build guide

Murphy is having the last laugh at my expense.

Received my 4U/400 chassis today, and my layout does not fit, by about 3mm on either side. So I will have to do my own angle brackets as I see that there is about a 8mm area of unused space on the angle bracket. If I move all the holes in the bracket outwards by say 6mm, I will have the gap I need to fit my PSU, as I want to do a dual mono construction.

Bugger!
 

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If you rotate the PSU boards 90º then it should fit with the connector beneath one of the amplifier boards. Not the best layout but it shouldn't be a problem.

Or you could build a bracket to mount the PSu boards on the side with the capacitors horizontal. Might even help with convection through the caps.
 
If you rotate the PSU boards 90º then it should fit with the connector beneath one of the amplifier boards. Not the best layout but it shouldn't be a problem.

Or you could build a bracket to mount the PSu boards on the side with the capacitors horizontal. Might even help with convection through the caps.

That is an option, although it would not look as nice. I will see if I can convince my OCD nature. ;)
 
Maybe just tap some new holes in the heatsink, and move the T bracket up just high enough to clear your caps.

Seems easier than starting over with a new L bracket.

Another option, but it would then mean that the heat won't spread well to the lower parts of the heatsink, making it less effective. I will think this over. Aluminium is quite cheap here. It is the machining that will cost the earth. I could drill it myself, but I would have to be super accurate with the TO-3 hole pattern. :scratch:
 
No.

The brackets must be flat against the heatsink with thermal grease and torqued properly to ensure maximum thermal transfer. Spacers will effectively turn the heatsink off.

Poor choice of words on my part - I meant spacers between the heatsink and the thin shiny steel brackets that connect the internal parts together. That would have the effect of moving the heatsinks (and whatever is properly attached to them) out L/R by a corresponding amount. Should be decently rigid if flat bar is used instead of washers. Front panel would cover any gap.

BK
 
henryve -

You could flip the perforated baseplate over, and use it with the lip pointed up, or just remove the perf plate altogether. If you are trying to eek out a few MM, it may be all that's necessary.

I need the spacing on the sides of the PSU boards so that the amp boards can sit at a level just below the top of the caps. I could certainly do that and it would move the tops of the caps lower so that I can mount the bracket closer to the centerline of the heatsinks.

This idea might just be worthwhile. The heatsinks won't be as efficient, but then again I do have the 400mm deep case, which means I have more heatsink than the 300mm Deluxe. I will just have to watch out for says when it is 40ºC outside.

Attached photo gives better idea of the problem. I want to send my transformer order in to Tomasz at Toroidy today. Since I am paying through my nose for shipping, I might as well get some good trafos.
 

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Hi,
What about changing the capacitors for some with lower hight? You would loose some capacity but it should be enough overall. A quick search on digikey revealed 1189-2848-ND which is 22000uF/35V and is only 42mm high. I guess the ones you're using are 50mm or more.
Martin

I could do that, but then have to weight the cost of getting 12 new caps, plus the shipping charge of $60 against the costs of doing 2 new T-brackets.

I will have plenty of time to decide while I wait for my Toroidy trafos via the slow boat from Poland.
 
OK, base plate reversed, 8mm standoffs on PSU boards used. Currently don't have 5mm standoffs in my stock.

Looks promising, though I will need to then use a secondary base plate for my trafos. No big deal. As they say, engineering is mostly creating a workable solution amongst a framework of constraints.
 

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I need the spacing on the sides of the PSU boards so that the amp boards can sit at a level just below the top of the caps. I could certainly do that and it would move the tops of the caps lower so that I can mount the bracket closer to the centerline of the heatsinks.

This idea might just be worthwhile. The heatsinks won't be as efficient, but then again I do have the 400mm deep case, which means I have more heatsink than the 300mm Deluxe. I will just have to watch out for says when it is 40ºC outside.

Attached photo gives better idea of the problem. I want to send my transformer order in to Tomasz at Toroidy today. Since I am paying through my nose for shipping, I might as well get some good trafos.



I wouldn't worry about NOT mounting the bracket on the centerline of the heatsink. Heat conducts in the aluminium in all direction. Impact of convection cooling on heatsink (by not centering) is probably minimal so long the heatsink is mounted the right way and there's proper ventilation.



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I wouldn't worry about NOT mounting the bracket on the centerline of the heatsink. Heat conducts in the aluminium in all direction. Impact of convection cooling on heatsink (by not centering) is probably minimal so long the heatsink is mounted the right way and there's proper ventilation.



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This is actually not completely true. The output devices or in this case the bracket should ideally be placed in the lower third of the heatsink to improve its effectiveness.
The diyaudio store deluxe cases have the heatsinks drilled in such a way for example.

Have you read EUVL's article on heatsinks in linear audio? It is available for download for free, it's very educating on the subject.