DIY :Pass F5 Turbo V2 Joshua & Ali's Documented Build

[jls001]

im thinking of having only 1 fan ( 120mm though )
exhaust from the top plate
mounted on the inside of the top plate

In that case, let us also think of making some vents for the air to circulate out of the cabinet. I am assuming the fan will suck in air and force-circulate it inside the cabinet. That needs to be thrown out through some other route. May be the bottom? And may be some holes on the back plate? I am guessing aloud here.

josh
i think personally i will go with the soft start
and give a skip to the speaker protection

btw
if we have to use the speaker protection
Om suggests this

its a high current stereo board
so only 1 board takes both channels

30A Stero Power Amp Amplifier Speaker Protection Board DIY by Yourself | eBay

I think skipping the speaker protection circuitry makes sense. We need to ensure correct bias and that ought to be enough protection. But let's keep the soft start.

P>s Josh i dont have the real estate to stick the rectifier board to the bottom do I ?
or can we squeeze it ?

Let me re-work the layout to place the rectification board on the bottom. I think there is room.

 

[jls001]

Its looks fine but how you will mount that above 5" transformer height.

I can mount below PS Cap bank too.

Let me try several options on paper:

1) mount rectifier board on the base plate. This will need some re-arrangement of the PS boards, but will be the best as base plate becomes heatsink.

2) mount below PS cap bank, if 7" internal height permits it. This will also allow usage of base plate as heat sink.

3) Independently above the toroidal. Will need some bracketing arrangement to support the board. The structure can be mounted to the frame structure. Separate heatsinks to be used. But they are cheap enough and easily available from Visha Electronics.

 

[magma]

In that case, let us also think of making some vents for the air to circulate out of the cabinet. I am assuming the fan will suck in air and force-circulate it inside the cabinet. That needs to be thrown out through some other route. May be the bottom? And may be some holes on the back plate? I am guessing aloud here.
.

no
mine is an EXHAUST fan

it exhausts hot air from inside the cabinet towards the outside from the vents in the top plate
upward

this works best
because in my experience fans "exhaust" better than they blow IN

and exhausting through the top plate is better because hot air naturally has a tendency to move upwards

as hot air is exhausted
cool air will automatically be sucked in

yes i need to think about side/front venting that will allow cool air to be sucked inward from the front
it should not be too difficult since if you see the flower sink , the first fin is tapered which automatically creates a vented slot
plus after we spoke yesterday
when i centre the sink after increasing the depth
i automatically gain the 30mm to play with as a vent

in your case we can have a small fan lowing in from the rear if you wish

or then incorporate a small inlet fan on the base plate
(of course this will be effective ony if you amp is on high feet so there is enough place for cold air to enter from bottom

Infact tall feet allows cold air to replace the hot air from even in between the fins!

i thought i would use my cerabases as footers
so i get 1.75 inches - plus it gives isoaltion - plus it looks good

 

[magma]

mananged to do some critical operations today

personally piloted the holes on the NC drill

heatsink and Cu spreader lapped and levelled - now drilled and tapped

 

[mpw]

no
as hot air is exhausted
cool air will automatically be sucked in

magma, that may not be true.

mpw
===============================================

 

[Simon Wires]

Just a quick thought came, while me trying to refresh my already forgotten Thermal engg paper.

Keep a tab on the distance between the source of heat & originating point ( bottom root) of fins. Though big fin heat sinks may help better in dissipating heat through convection, the heat to be dissipated had to to reach there by conduction, which is grades down if that distance goes up.

Please note, this is not about thickness of fins, but about the heat conducting distance. In case you face any such difficulty, grind the base of the fin, and reduce the thickness.

A few technical study readings could be referred with Fourier law of conduction.

Best wishes, always

 

[magma]

.

Keep a tab on the distance between the source of heat & originating point ( bottom root) of fins. Though big fin heat sinks may help better in dissipating heat through convection, the heat to be dissipated had to to reach there by conduction, which is grades down if that distance goes up.

Ple

thank you very much simon
your inputs are much appreciated

i did have some idea about thi
(you confirmed it )

hence the copper aluminium heatsink

Also if you see
i did grind down the base

also another point to note is this Flower sink
it should fair much better than the traditional designs
due to its increased surfce area and orientation of the fins - how the air moves between them etc etc

I think one of Oms sinks also has this airflow design

i had this checked at a heatsink manufacturer
and that how one of my old clients choose the sink in the first place

 

[Simon Wires]

Hi Magma,

Choosing flower sink is an excellent idea, which gives more dissipation through convection, than those traditional ones.

My apprehension here is, though copper is an excellent conductor, but its presence between sink and heat source may lengthen the travelling distance of heat, and hence lowers the conductivity.

Since we dont have a clear cut data about the source temperature and dimensions, its difficult to arrive at a conclusion; rather your experience will pay better results there. If any difficulty faced, you may always remove that copper strip..

I'm not sure if, I'm responding here, without understanding the full picture..

 

[magma]

Copper conducts heat 3 times faster than aluminium

the job of the spreader is to conduct as fast as possible keeping the devices as cool as possible

Also the surface area of contact between the copper and the sink is almost 10 times more than what it would be with the mosfets directly attatched

Umm
i have done a bit of research on this and taken some trusted opinions
in my experience this should work out well

 

[vktarun]

Great Build and very Informative thread,

Have observed in attached picture that you have first drilled a hole in the Heatsink , Now what is the next step I mean to say how is thread made in the hole in which screw will go.

How is bit size decided for making the hole?

Regards,

Vipin.

 

[quad]

Great Build and very Informative thread,

Have observed in attached picture that you have first drilled a hole in the Heatsink , Now what is the next step I mean to say how is thread made in the hole in which screw will go.

How is bit size decided for making the hole?

Regards,

Vipin.

How to Use a Tap: 9 Steps (with Pictures) - wikiHow

 

[magma]

the most imp[ortant part of tapping is the drilling before it and then the tap entry

infact correctly drilling a hole requires you to actaully change 3 drills

a pilot
the size drill
the Quatersink drill for tap entry

Tapping steps listed above are fine
except they have shown a home tap set
industrial tap sets come with larger handles that allow you to get perpendicularity

the pre drill MUST be done on a drill press
A hand drill machine for me is an absolute NO no

Maximum tap breakage occurs because the drill was never perpendicular to begin with

 

[jls001]

@magma: by any chance are you using threaded inserts on the sink (or any aluminium part where a hole is to be drilled)? How do they make holes for the hex threaded inserts? They look really neat.

 

[jls001]

Small progress from my side: Perfect Metal's N56 heatsink will be ordered tomorrow. Size is 9 inch per piece (each heatsink is 215 mm wide and has 75 mm fin depth, as shown in previous post # 32 on this thread). Two to a side. Cost is Rs 1862 per 9" piece, including cutting. Add packing, shipping and taxes. Total comes to Rs 7963.

 

[magma]

@magma: by any chance are you using threaded inserts on the sink (or any aluminium part where a hole is to be drilled)? How do they make holes for the hex threaded inserts? They look really neat.

why do you want to use inserts
just tap the sink directly

its better that way

metal inserts are normally press fitted

maybe i have not follwed the type of insert you are mentioning
post pic

 

[magma]

Small progress from my side: Perfect Metal's N56 heatsink will be ordered tomorrow. Size is 9 inch per piece (each heatsink is 215 mm wide and has 75 mm fin depth, as shown in previous post # 32 on this thread). Two to a side. Cost is Rs 1862 per 9" piece, including cutting. Add packing, shipping and taxes. Total comes to Rs 7963.

thats a 1000 rs saving from the mumbai re seller
:clapping:

 

[captrajesh]

Small progress from my side: Perfect Metal's N56 heatsink will be ordered tomorrow. Size is 9 inch per piece (each heatsink is 215 mm wide and has 75 mm fin depth, as shown in previous post # 32 on this thread). Two to a side. Cost is Rs 1862 per 9" piece, including cutting. Add packing, shipping and taxes. Total comes to Rs 7963.

That is far cheaper than Arihant Aluminium, Chennai. I paid 7.6k for 4 Nos of 8" width; got ripped I guess.:sad:

 

[bibin3210]

I paid Rs. 1765 for 204mm N56 (Including Cutting, Tapping and Black Anodizing) from Perfect Metals plus 5.5% CST and Rs. 150 for Packing and forwarding.

Thanks,
Bibin

 

[magma]

some more work done

pure aluminium framework , copper speader and sinks test fitted

Effective sinking 16kgs of aluminium and copper




air tunnel checked
with colored smoke

inlet from the sides and base
exhaust from the top

need to do the top plate and rear plate now

 

[sachu888]

It looks massive:clapping:

Regards,
Sachin