DIY Enclosure/Cabinet for PowerAmp & PreAmp

[bibin3210]

Updated the list and adding the dimensions for easy reference:

Pass B1 Cabinet

Inner Dimension (WxDxH) in inches : 12.5 x 9.5 x 3.15
Sheet Metal Works using 1.2mm CR sheet and powder coating : 1380 INR
Acrylic work and laser engraving front(9mm) and back(4mm) panel : 1052 INR

Total : 2432 INR





Pass F5 Cabinet
Inner Dimension (WxDxH) in inches :17.25 x 15.5 x 8
Sheet Metal Works using 1.2mm CR sheet and powder coating : 2300 INR
Acrylic work and laser engraving front(12mm+9mm) and back(6mm) panel : 4160 INR
Heat Sink : 2500 INR

Total : 8960 INR






Pass B1 Cabinet GB members
----------------------
1) apk
2) mbhangui
3) thecoolestone
4) rohitmusic
5) ruenigma
6) denom
7) Santy
8) keith_correa (Wooden Front Panel)
9) santnai


F5 Cabinet GB members
-----------------
1) gvenu x 2 (without heatsink)
2) captrajesh (without heatsink)


Thanks,
Bibin

 

[Audiodoc]

Even I was interested in the F5 amplifier cabinet however am still skeptical (considering the massive vertical ones FM anilva has used, he being the pass amp guru here) with the thermal stability with horizontal fins. Has someone tested the same with a pilot F5 build.

I had plans of building the cab vertically to have 12 x 12 inch vertical side panels for passive heat dissipation (akin to radiators used in winters). These ML beauties will give an idea.

 

[anilva]

Those heatsinks setup that way will not work IMO. You need to have two fans on either side evacuating hot air from the fins constantly to be able to run it with required bias of 600 mV bias for standard F5. The Turbo is completely ruled out of this setup. The height if the cabinet is also not sufficient to have enough heatsink area even if one were to mount the fins aligned vertically for Turbo.

I am talking about Bibin's F5 cabinet here.

Regards

 

[bibin3210]

Those heatsinks setup that way will not work IMO. You need to have two fans on either side evacuating hot air from the fins constantly to be able to run it with required bias of 600 mV bias for standard F5. The Turbo is completely ruled out of this setup. The height if the cabinet is also not sufficient to have enough heatsink area even if one were to mount the fins aligned vertically for Turbo.

I am talking about Bibin's F5 cabinet here.

Regards

Hi Anil,

Can you please suggest me an appropriate dimension for the F5 Turbo? I can modify the design according to that and it will be helpful for gvenu and captrajesh to mount the heatsink with vertical fins.

And if there are more request for F5 cab i will try to provide 6mm aluminium panels on front and back.

Thanks,
Bibin

 

[baswamin]

Bibin,

Anil has used two N56 heatsinks (see link below) together. They will be 430mm in total (the depth). Your cabinet is ~394mm. If you can make is 430mm, we can mount two of these heatsinks vertically on the sides. I think this is bare minimum required for F5 V2 turbo.

If you can do this and also modify the holes in the bottom plate to mount the PCB's made by Om, then many FM's may be interested in F5 cabinet.

N56 heatsink

Thanks

 

[anilva]

Bibin,

Anil has used two N56 heatsinks (see link below) together. They will be 430mm in total (the depth). Your cabinet is ~394mm. If you can make is 430mm, we can mount two of these heatsinks vertically on the sides. I think this is bare minimum required for F5 V2 turbo.

If you can do this and also modify the holes in the bottom plate to mount the PCB's made by Om, then many FM's may be interested in F5 cabinet.

N56 heatsink

Thanks

You are right. 430mm is the heatsink width (2 nos. N56 mounted side by side) and height is around 8" for the heatsink. That will determine the cabinet dimensions for Turbo V2. The standard F5 can do with 6" height with similar heatsinks.

 

[anilva]

If you can do this and also modify the holes in the bottom plate to mount the PCB's made by Om, then many FM's may be interested in F5 cabinet.

PCBs do not mount to the bottom plate but directly to the heatsinks along with the MOSFETs.

 

[ranjeetrain]

Yesterday I went to the sheet metal workshop to see the completed work, the preamp cabs are ready but i am not satisfied with the finish of the powder coating. There were small dots and they had agreed to repeat the powder coating after sand blasting the current layer. So mostly on Monday or Tuesday they will finish their work.

Posting here few pics i took yesterday on my mobile. Sorry for the poor quality of the images.










Top cover for the Class A Amp cab (F5 and Hiraga)



Thanks,
Bibin

Lovely work Bibin :clapping:

Would you be able to do some other cabinet for me if I provide you the design?

 

[bijinmb]

Lovely work Bibin :clapping:

Would you be able to do some other cabinet for me if I provide you the design?

Sure, We can help/assist you on that. Only trade off is time and patience for a custom design and its obvious.

You know it took almost couple of months to get everything regarding the cabinets work done.

The main headache is dealing with the sheet metal work engineers. They are highly unreliable on the time frame they commit to us.

One reason I have figured out is, they are not much interested in dealing with 2-3 cabinet's work and apparently its natural phenomenon which happens in many business.

 

[ranjeetrain]

Thanks, will send you the design on email/pm.

 

[bibin3210]

You are right. 430mm is the heatsink width (2 nos. N56 mounted side by side) and height is around 8" for the heatsink. That will determine the cabinet dimensions for Turbo V2. The standard F5 can do with 6" height with similar heatsinks.

@Anil, @baswamin

Thank you for providing the suggestion and correct dimensions. The depth of the cab can be increased very easily and it doesn't affect other designs since the height suggested by Anil is 8" which is same as the current height of the cabinet.

So the new dimension will be :
Inner Dimension (WxDxH) in inches :17.25 x 17 x 8

Anil can you please comment on this new dimension? Do i need to increase the width ?

Thanks,
Bibin

 

[omishra]

Sorry for cross posting.

What about these?

I posted reference here .

 

[baswamin]

Om,

We need to decide on one heatsink unless Bibin can provide different depths for different heatsink design.

Do you know if one piece of the heatsink you show is enough for F5 V2? Say height is 17.25" or 438mm, width is 300mm?

Thanks

 

[omishra]

Om,

We need to decide on one heatsink unless Bibin can provide different depths for different heatsink design.

Do you know if one piece of the heatsink you show is enough for F5 V2? Say height is 17.25" or 438mm, width is 300mm?

Thanks

IMO, I think so. Though I did not calculate deg C/W, I have following reasons for this.

1. That heatsink has 792 square inches of surface area with outer ambiance which comes roughly 5.5 square feet. This supposed to be better passive cooling by means of big heat radiator.
2. Base is 12 mm thick means no hotspot on heat spreader with radius of 120mm around device. If we mount at center of 150mm heatsink still its 75mm on either side of device, well within limits. So heat spreading is good.
3. Its weight is 7.5Kg for that piece, provide good thermal inertia for absorbing thermal shocks. It means no sudden rise or drop in temperature.

Bigger fins means it could cooled by natural ambiance ventilation, smaller fins mean forced ventilation is required (e.g. fan etc) Vertical fins means air can move from down to upside naturally. For Horizontal fins air below fins is stalled and heat transfer from metal to air is stopped. It mean that much efficiency is lost.

BTW all above will be verified once I build my F5t using this heatsink.

 

[Santy]

Just wondering.
Instead of stuffing in monstrous heat sinks adding to the weight and size, why not have a fan on a smaller heatsink?

I got this fan for my PC and it is absolutely silent and has amazing air flow.
Ofcourse, this may be too big, there are smaller and cheaper versions available which are probably even more silent.

Infact I also use USB powered LED Fans bought from Ebay for my AVR and AMP since they are placed inside 5 side closed racks. They keep them cool all the time.

 

[bijinmb]

Just wondering.
Instead of stuffing in monstrous heat sinks adding to the weight and size, why not have a fan on a smaller heatsink?

I got this fan for my PC and it is absolutely silent and has amazing air flow.
Ofcourse, this may be too big, there are smaller and cheaper versions available which are probably even more silent.

Infact I also use USB powered LED Fans bought from Ebay for my AVR and AMP since they are placed inside 5 side closed racks. They keep them cool all the time.

You are correct there are some good cooling fans available, but the question is where are you going to place the fan?

A. Outside the cabinet and over the fins ?

Pros:
1. Efficient cooling.

Cons:
1. Opened to accidental touch and getting hurt.
2. Neat wiring will be a headache.
3. Can't stop the noise created due to turbulence when air passes through the fins if the fan has Amazing air flow especially.
4. Additional power usage.
5. Fixing properly is a bit tiresome work since one can't compromise on cabinet's external look and aesthetics.

B. Inside the cabinet ?

Pros:
1. Not opened to accidental touch and getting hurt.
2. Neat wiring is possible.
3. Noise due to turbulence or whatever will be very less audible.
4. Fixing is not that a big headache since we don't need to take much care of look and aesthetics..

Cons:
1. Won't cool efficiently at-least at the rate F5 Turbo demands.
2. If fan fails there is more chance that we don't get that noticed and more likely of getting damage to the Output transistors due to over heating.

 

[sachu888]

2. If fan fails there is more chance that we don't get that noticed and more likely of getting damage to the Output transistors due to over heating.

100% agree with the above statement.

Regards,
Sachin

 

[Santy]

B. Inside the cabinet ?

Pros:
1. Not opened to accidental touch and getting hurt.
2. Neat wiring is possible.
3. Noise due to turbulence or whatever will be very less audible.
4. Fixing is not that a big headache since we don't need to take much care of look and aesthetics..

Cons:
1. Won't cool efficiently at-least at the rate F5 Turbo demands.
2. If fan fails there is more chance that we don't get that noticed and more likely of getting damage to the Output transistors due to over heating.

We could place fan inside the cabinet just above the heat sink, and there should be plenty of holes on the case. Screws could go into the same holes made for ventilation. We can use LED fans, it will look cool and also indicate if it is functioning. It also helps to suck out some dust before they settle on the components.

If the sink is extending to the rear side, the fans could be placed on the back of the cabinet as well. Something like this:

Just a suggestion to reduce the weight and also increase cooling efficiency

 

[omishra]

2. If fan fails there is more chance that we don't get that noticed and more likely of getting damage to the Output transistors due to over heating.

This may lead to fire or smoke or blowing of speakers if not protected. This is after much thought I ruled out forced/active cooling and dependent on natural ventilation passive cooling.

 

[Santy]

This may lead to fire or smoke or blowing of speakers if not protected. This is after much thought I ruled out forced/active cooling and dependent on natural ventilation passive cooling.

Yes, there is always a risk of fan failure. No doubt about it. But I guess there are thermal protection circuits also available? I have seen many power amps with this feature.