DIY: Pass F5 turbo v2 initiated

[pdhanwada]

Kroyin,

I thought so. As long as the transformers are shielded they should be fine. I will have them one over the other using a separator.

50mm (trans) + 50mm separator + 50 mm(trans) vertically.

They have a guide screw hole through which I will pass the screw and tighten it to the base.

Thanks
Pandu

 

[kroyin]

You are gonna bulid a loft make sure the house doesn't crash down

 

[pdhanwada]

You are gonna bulid a loft make sure the house doesn't crash down

nice one. I agree structurally it needs to be strong.

 

[omishra]

My cabinet progress.

4 pieces of 205mm by 150 mm heatsinks
front and back plates 7 mm thick aluminium plates
Anglers on all the edges which will tie the front, back plates, heat sinks, top and bottom plates together.
Anglers are 3.5 mm thick
My fins are 82 mm.
Will attach both the heat sinks using 2 anglers one at the top and other at the bottom.

My inside of the cabinet is 10.5 X 16 in. So kind of conjusted.

As the thickness of the toroid is 50mm and magnetically sheilded can I place the two toroids one over the other.

Will run a 6 inch nut bolt thru the two toroids and fix them to the cabinet.

Will Place a separator of 18mm thick plywood in between. Also will leave about 25 mm space between the toroids

If I can use this arrangement I can work comfortably for the rest of the three boards on the bottom. letme know if this poses any problems.

Will place the amp pcbs on the heat sinks such that they centered depth wise so that heat dissipation happens evenly.

Not planning to do any welding of the heat sinks as I think by placing one pair of mosfets on each heat sink, the distribution of heat should be even.

Also not planning to use any heat spreader as done by buzzforb in DIYaudio.

Thanks
Pandu

IMO no need of heat spreader you can have those MOSFETs on both side of join. Anyway those two part of heatsinks will be thermally coupled. Use some heat paste below joining metal.

The transformer where it is laying could be made vertical and both could be accommodated. Prepare some L of metal which could hold transformer vertically against bottom plate. Even your idea of using single bolt between both transformer with separator of ply is simple and good. Just you have to keep all wire outlet side of transformer away from input signal side because the static shield is weak and magnetic leakage is more at that side of transformer.

Even I am thinking of having one 1/2" lightweight iron angle welded to make chassis to which all heatsinks front and back plates attached. Because having all weights attached with M3/M4 bolts where it's threaded into all aluminum. Will that hold it together? How long? Again there are 7Kg transformers.

 

[pdhanwada]

IMO no need of heat spreader you can have those MOSFETs on both side of join. Anyway those two part of heatsinks will be thermally coupled. Use some heat paste below joining metal.

The transformer where it is laying could be made vertical and both could be accommodated. Prepare some L of metal which could hold transformer vertically against bottom plate. Even your idea of using single bolt between both transformer with separator of ply is simple and good. Just you have to keep all wire outlet side of transformer away from input signal side because the static shield is weak and magnetic leakage is more at that side of transformer.

Even I am thinking of having one 1/2" lightweight iron angle welded to make chassis to which all heatsinks front and back plates attached. Because having all weights attached with M3/M4 bolts where it's threaded into all aluminum. Will that hold it together? How long? Again there are 7Kg transformers.

Yesterday I bought a 8mm dia MS STEEL 6 inch screw. I was able to send that screw thru the hole of the transformer and create a loft. I think the idea is simple and good as you said.

I want to use nuts and bolts between front plate and angler where as I want to use M5 screws between Angler and the heat sinks.

These screws take the load of heat sinks only. one of the Transformer will rest on base and the other on a ply. And the loft is well supported by a 8mm Screw which i feel is thick enough to take the load.

With regard to the lead placement of the transformers I will consult you in the final fitting.

Thanks
Pandu

 

[omishra]

With regard to the lead placement of the transformers I will consult you in the final fitting.

One more thing... Take care that long bolt is not shorting to chassis at other end.

 

[quad]

One more thing... Take care that long bolt is not shorting to chassis at other end.

Yes, that is a very important caveat when using Toroids. Google for "Shorted turn".

 

[pdhanwada]

quad and Om,

Thanks for pointing out. I had planned such that only the bottom portion sits on the plate and top portion does not touch the chasis.

Thanks

 

[omishra]

I got all non imported parts and connector from local market. This way all wires connecting to PCBs and ground lifting bridges will be terminated as below. All will have HQ rubber sleeves which will avoid accidental touching and shorting.

All connectors in place includes -

• 6.3mm PCB tab, terminal and sleeves - used for amp boards
• 1mm X 2 PCB pins, 4.8mm terminal and sleeves - used for Power supply PCBs

 

[pdhanwada]

I got all non imported parts and connector from local market. This way all wires connecting to PCBs and ground lifting bridges will be terminated as below. All will have HQ rubber sleeves which will avoid accidental touching and shorting.

All connectors in place includes -

• 6.3mm PCB tab, terminal and sleeves - used for amp boards
• 1mm X 2 PCB pins, 4.8mm terminal and sleeves - used for Power supply PCBs

Om,

Good work. Keep it up.
Thanks

 

[omishra]

Given some thoughts over placement of central part of amplifier.

• This would have to handle large weight of two transformers.
• There is some rectifier board + (optional)some softstart cum thermal cutoff board

2 filter boards.

I am thinking to have to layer approach to make it fitted into 12" X 12" space.

What do say if I build a frame of 1-2mm thin Iron 0.5"(W) angle to dimension 12"(W) X 12"(L) X 5"(H)?
This will allow me to -

1. Attach heatsinks from sides, face and back plates along with top/bottom plates.
2. Put welded partition which will support toroidal transformers as well as all boards too.
3. Bear weight distribution and support the structure.

 

[pdhanwada]

Om,

Earlier today, I gave up the idea of doing it myself. I went to a place called fatehnagar here in hyderabad where lot of milling and metal cutting works is undertaken. To get the box done without the top and bottom plate it would cost me Rs 1000. I think it is fair amount because it is not easy get it done without using clamps.

There are lot of holes to be done. Lot of tapping to be done.

With regard to the idea of having multi layered approach in the layout is fine.

can you point me to the soft start board which you are using.

WIth regard to the idea of creating a 1mm to 2 mm angler frame to which you will attach all the heat sinks, front plates, top plates is good. I would rather use strong MS Angler instead of aluminium. MS steel is stronger than aluminium.

You need use Angler on the vertical portion of the cabinet. In all other places you can use 1 in wide Ms steel to which you can make holes and send them to the heat sinks.
To attach bottom plate to the you probably would need certain cross bars on the bottom portion too.

Take welding help which should make your life easier.

Once you get the structure done you can add one piece after the other which is a good thing.

In my case everything is getting up at one shot was kind of cumbersome as we dont have big clamps

 

[omishra]

Om,
can you point me to the soft start board which you are using.

Its here on fleabay Class A power delay soft-start temperature protection board 110V/220V | eBay

 

[kroyin]

To everyone designing a chassis pls make sure to have clear access to the trimpot (make sure you can turn it with a screwdriver) with all boards & caps in place.It would be nice if you also have access to the source resistorz

 

[pdhanwada]

To everyone designing a chassis pls make sure to have clear access to the trimpot (make sure you can turn it with a screwdriver) with all boards & caps in place.It would be nice if you also have access to the source resistorz

I agree and I am have been thinking about it.

I want to locate the trimpot. By looking at the pictures provided as part of the thread I am not able to tell where it is.

Can anybody post high resolution pictures of the PCB.

Thanks
pandu

 

[pdhanwada]

Its here on fleabay Class A power delay soft-start temperature protection board 110V/220V | eBay

As part of the pass F5 V2 We do have the protection thru thermistors. Do you feel we need more protection cirtuitary.

I guess we need one per each channel.

Thanks
Pandu

 

[pdhanwada]

Its here on fleabay Class A power delay soft-start temperature protection board 110V/220V | eBay

It is a ac input so one is enough.

thanks
pandu

 

[baswamin]

From that website, it looks like it is temperature protection, does it do soft start also (delaying the input power up)? Sorry for this basic question.

Additionally, do any one know where to get the cabinets made in Bangalore? Heatsinks can be procured from the link omishra provided earlier in the thread but I am clueless about the cabinets and how to integrate heatsink with it.

Thanks

Its here on fleabay Class A power delay soft-start temperature protection board 110V/220V | eBay

 

[kroyin]

We got hold of some Nichicon & Rubycon 10000uF 50V in kolkata for 120/- each.
Both are rated at 105C and both are fakes.
I checked up the datasheets and Nichicon LK and Rubycon USR both had temperature rating of 85C.

So if you are planning to buy a brand name cap with a price too good to be true is ending up with fakes

 

[sachu888]

We got hold of some Nichicon & Rubycon 10000uF 50V in kolkata for 120/- each.
Both are rated at 105C and both are fakes.
I checked up the datasheets and Nichicon LK and Rubycon USR both had temperature rating of 85C.

So if you are planning to buy a brand name cap with a price too good to be true is ending up with fakes

Yes most of the locally available caps are fakes.The cheapest I could find on authorised sources are Cornell Dubilier and Panasonic branded 10000uf 63V @Rs235-250/cap(approx).

Regards,
Sachin