DIY: Pass F5 turbo v2 initiated

[anilva]

Capt.

Your concerns on signal wire length are completely misplaced and so is your assumptions of how to place the heatsinks and the RCA sockets. Just place them as per convenience and run the signal wire to the PCB. No problem. In my case the heatsinks are mounted on either side of the cabinet and the RCA sockets are mounted to the back plate of the amp. You have seen the pictures.

Please keep it simple.

Regards

 

[rohitmusic]

How many people will be needed to lift Mishra sir .....:lol:

Lift Mishra Sir??

I am ready to be one of them in rejoice, once the amp sings!

Nice to see things taking shape

 

[captrajesh]

Your concerns on signal wire length are completely misplaced and so is your assumptions of how to place the heatsinks and the RCA sockets. Just place them as per convenience and run the signal wire to the PCB. No problem. In my case the heatsinks are mounted on either side of the cabinet and the RCA sockets are mounted to the back plate of the amp. You have seen the pictures.

Thank you for your opinion Anil ji, you saved me a lot of botheration. I sure will keep it simple and use three 6" high heat sinks on either sides of the cabinet.

In your pic, I'm not able to make out how the MUR diodes of PS rectifier mounted on to the heat sinks. I'm told that these do not require such an elaborate heat sink. Hence, would it be ok to use a heat sink of lesser dimensions for mounting these diodes. I'd then be fixing that heat sink on to the bottom plate inside the cabinet.

 

[omishra]

Lift Mishra Sir??

I am ready to be one of them in rejoice, once the amp sings!

Nice to see things taking shape

Please don't lift me, . I am 70Kg, so careful Rohit. If fallen on anyone then it could be harmful for that person.

Captain,
Input RCA could be shielded and same time we are keeping output wires short here.
About your and mine heatsinks - these are meant for tunnelling forced air from one end to another. The grooves which you are planning to cut are 'T' shaped where suitable nut could be insert and slide to suitable position in that grove. You can tight using bolt into it. This was to attach Bakelite sheets. Even in my case i found attaching top and bottom plates were easy that way. Also there are opposite facing slots for insertion of bakelite sheet.

Or something like this could be thought.

 

[captrajesh]

Input RCA could be shielded and same time we are keeping output wires short here.

Yeah that's what I've decided after reading Anilva's post.

About your and mine heatsinks - these are meant for tunnelling forced air from one end to another. The grooves which you are planning to cut are 'T' shaped where suitable nut could be insert and slide to suitable position in that grove. You can tight using bolt into it. This was to attach Bakelite sheets. Even in my case i found attaching top and bottom plates were easy that way. Also there are opposite facing slots for insertion of bakelite sheet.

Yeah, I was told about the usage of those grooves by the dealer's employee. It will not be of much use in my case and also adds to the 'fugly' quotient; so I've decided to get rid of them. I'll make 3 Nos. of 6" tall heat sinks on either side exactly the same way that build pics that you've linked.:thumbsup:

In your pic, I'm not able to make out how the MUR diodes of PS rectifier mounted on to the heat sinks. I'm told that these do not require such an elaborate heat sink. Hence, would it be ok to use a heat sink of lesser dimensions for mounting these diodes. I'd then be fixing that heat sink on to the bottom plate inside the cabinet.

Could you guide me on the above query?

 

[anilva]

In your pic, I'm not able to make out how the MUR diodes of PS rectifier mounted on to the heat sinks. I'm told that these do not require such an elaborate heat sink. Hence, would it be ok to use a heat sink of lesser dimensions for mounting these diodes. I'd then be fixing that heat sink on to the bottom plate inside the cabinet.

No special heatsinks are required for MUR diodes on the amp PCB. Use small individual heatsinks which we use for voltage regulators such as LM317. These diodes are normally off and not conducting till the bias reaches around 1A per output pair (around 400 mV of bias voltage across the source resistors of Mosfets). They conduct when the amp is driven into very complex speakers loads at high power levels. Many people across DIYA including me have not seen the diodes turn on even once....They don't get hot at all.

Cheers

 

[omishra]

Yeah that's what I've decided after reading Anilva's post.

Yeah, I was told about the usage of those grooves by the dealer's employee. It will not be of much use in my case and also adds to the 'fugly' quotient; so I've decided to get rid of them. I'll make 3 Nos. of 6" tall heat sinks on either side exactly the same way that build pics that you've linked.:thumbsup:

Could you guide me on the above query?

One more guy made 6 channel F5 amp.

See he is using heatsink same like mine, here.

 

[omishra]

Some more progress without any handles so far. I hope after anodizing it will look better than this. It's not bad at all!

Now tested fitting of all holes and so far alright. Made those ventilation holes in big plates by spending 3.5 hrs.

 

[sachu888]

Hi om,
Looking very professional.I can see the hardwork:clapping:

Regards,
Sachin

 

[kroyin]

Excellent but it begs to be cut in the middle and made into monoblocks

 

[omishra]

Excellent but it begs to be cut in the middle and made into monoblocks

Thanks! Now its not possible for me as chassis is made inside for better management and space is designated where I would keep this. Also handle will help for moving it around.

 

[captrajesh]

Now tested fitting of all holes and so far alright. Made those ventilation holes in big plates by spending 3.5 hrs.

Om, for hot air from the cabinet to escape, the ventilation holes are best placed on the top plate IMHO.

 

[omishra]

Om, for hot air from the cabinet to escape, the ventilation holes are best placed on the top plate IMHO.

Yes there is some gap!

Actually (not in pic) there is 2-3mm gap below top plate at overlap of structure rod and side plate. Same with bottom plate but its less, 1-2mm. This came from machining tolerances and I am planning to take advantage of that.

 

[sann]

My cabinet is shaping up @ Om Labs:

Another angle:

For a change, Om is finalizing a layout which is a bit sober than this one:

Just kidding Om, there is so much to learn from the way you built a cab for the heatsink which was difficult to deal with.
Regards,
Sann'

 

[baswamin]

Sann,

Your cabinet build is coming along well. I had couple of queries.

1. I see a L-bracket at the bottom in first pic. Where did you source this from? I cant see to get hold of one such bracket locally here. Is there any specific name for it?

2. You have drilled holes in heatsinks. How do you know how deep to drill? I mean if we start drilling, we should not drill through the bottom plate completely. How do you ensure you have drilled just the right depth?

Thanks

 

[sann]

1. I see a L-bracket at the bottom in first pic. Where did you source this from? I cant see to get hold of one such bracket locally here. Is there any specific name for it?

I sourced it from the same metal seller shop from where I bought the AL sheet for the cab, It is called L bracket only, there were different sizes and thickness, and we picked the one which best suited.

2. You have drilled holes in heatsinks. How do you know how deep to drill? I mean if we start drilling, we should not drill through the bottom plate completely. How do you ensure you have drilled just the right depth?

Luckily, the heatsink manufacturer delivered the heatsink with holes drilled and tapped, we just told them the sizes of the holes (M3 and M5) and they drilled the standard size holes.

Regards,
sann

 

[omishra]

My cabinet is shaping up @ Om Labs:
...
For a change, Om is finalizing a layout which is a bit sober than this one:

Just kidding Om, there is so much to learn from the way you built a cab for the heatsink which was difficult to deal with.

Those heatsinks are 0.66C/W/4". That comes 0.22C/W/12". Means for 100 watts it will add another 22C over ambiance. Also it won't get damaged if fall from 5Ft height. Thanks to bolting and internal bracing.

Sann,
1. I see a L-bracket at the bottom in first pic. Where did you source this from? I cant see to get hold of one such bracket locally here. Is there any specific name for it?

That's 300mm length piece of 'L' angle with 1" width and 4mm thickness.

2. You have drilled holes in heatsinks. How do you know how deep to drill? I mean if we start drilling, we should not drill through the bottom plate completely. How do you ensure you have drilled just the right depth?

Looking at the cab making difficulty we told manufacturer to add required holes/tapping around heatsink so that cabinet build can be done within 30 minutes after plates are ready.

 

[sann]

We made further progress today, we got the 3mm AL sheet cut to the size for top, bottom and back plate and 6mm from the face plate. Also got the holes drilled for air vent on top and bottom plates, but these holes which were drilled by the machine come nowhere close to the holes which Om drilled manually in terms of alignment and finish.

After cutting the plates we drilled holes for attaching them to the heatsink.
Few images:

Top:

Bottom:

Back:

Front:

The cab seems sturdy, and seems it should be able to take the 5+ kg's more which will go in, in the form of transformer, stuffed boards and connectors.

Thanks,
Sann

 

[Audiodoc]

Great work with the ventilation holes. It is back breaking business!

Though Captain is right that these may not be as effective as exhausts but they will act as intakes if you add a few on the top plate.

 

[captrajesh]

Though Captain is right that these may not be as effective as exhausts but they will act as intakes if you add a few on the top plate.

If you see the construction of any commercial amplifier, they have air circulation vents not only at the top but also at the bottom. As the air around the components that are hotter than the ambient temperature gets heated by way of conduction, convection and radiation, it rises up and the vents on the top plate facilitate it's movement out of the cabinet.

At the same time, the vents located at the bottom plate facilitate movement of fresh air of same volume to take the place of air that has moved out and this cycle continues.