Pass F5 ready to power up

Rega Turntables
Dear sir

i have hardly any knowledge compared to you and most here on the forum ; but that heatsink you are using looks to me like an 8 inch extrusion with 1 inch fins
cut at a 10-12 inch lenght )

i think if im not mistaken you are using the second extrusion here


This is by far very less than what is required for an F5 as far as i know
Also you have placed the sink with the fins horizontal rather than vertical
This is not optimum. Fins should always be kept vertical ( hot air moves upwards )
by keeping fins horizontal you do not allow the hot air to escape.
By doing this you have brought efficiency of the already lower rated sink to 60%

P.S please do not state Nelson First watt F5 to counter this suggestion
Those are bloody customised sinks with 3.75 inch long fins that have a lot of spacing between them and most importantly are shaped to curve upwards for heat dissipation

i think nelsons paper gives a hint about the extrusions to be used to
Also you can calculate the heat in a website ( i forget which one - ill post it later )
i think nelson suggests a sink of the following specs
8 inch extrusion at minimum
12-16mm thick base
2.5inch preferably 3 inch long fins from the base
I think in another place the wieght is also specified at 3.5kgs/sink!

This is something you should consider




Please not this is just my opinion which is most probably wrong considering i no nothing about electronics
 
Last edited:
magma said:
Dear sir

i have hardly any knowledge compared to you and most here on the forum ; but that heatsink you are using looks to me like an 8 inch extrusion with 1 inch fins
cut at a 10-12 inch lenght )

i think if im not mistaken you are using the second extrusion here


This is by far very less than what is required for an F5 as far as i know
Also you have placed the sink with the fins horizontal rather than vertical
This is not optimum. Fins should always be kept vertical ( hot air moves upwards )
by keeping fins horizontal you do not allow the hot air to escape.
By doing this you have brought efficiency of the already lower rated sink to 60%

P.S please do not state Nelson First watt F5 to counter this suggestion
Those are bloody customised sinks with 3.75 inch long fins that have a lot of spacing between them and most importantly are shaped to curve upwards for heat dissipation

i think nelsons paper gives a hint about the extrusions to be used to
Also you can calculate the heat in a website ( i forget which one - ill post it later )
i think nelson suggests a sink of the following specs
8 inch extrusion at minimum
12-16mm thick base
2.5inch preferably 3 inch long fins from the base
I think in another place the wieght is also specified at 3.5kgs/sink!

This is something you should consider




Please not this is just my opinion which is most probably wrong considering i no nothing about electronics
Click to expand...

Magma,

THanks. I am in full agreement on the heatsinks. Your observations are right. My heatsink is what I could get in the market with limited options. The size is 12" length, 8" high and 2.5" fin height. Fairly big and heavy.

I would like to take from you, if you have something that suits F5 design.

Cheers.
 
dear anilva

im not a heatsink dealer and have no commercial intrest in heatsinks

it just that my business has me heavily invested in Aluminium extrusions and so i come in contact with all kinds of extrusions that includes sinks too
and hence sometimes know heatsink manufacturers as well

it was them who explained that fins should always be vertical.
they showed me softwares and explained how the sink actually works and how they caluculate sink requirements
what are the effects if fins are placement horizontal

SINKS are classified according to their width because it is this width which is mounted
For e.g yours is an 8 inch extrusion


what matters most is the thickness of the base and the length of the fins and ofcourse the no. of fins

the pic ive posted is of a 10 inch extrusion
16mm base
82mm fin height

what you can try and do is mount the sink so that the fins are vertical ( like how i have posted in my pic )
yes for an 8 inch extrusion the height youve got is 12 inches which would make the amp an ODD 12 inches high

what you can try is see if you can cut it at 6 inches and load both extrusions side by side for a 16 inch breadth
Of course you need to have a nice way of brazing the pieces together with pure AL ingot
you amp will then be 16 inches deep and 6 inches high

Ideally you require longer fins though
Are you sure those are 2.5 inch fins? looks closer to 1.5 inch
i havent come across such an extrusion ( 8 inch with 2.5 inch fins!) in my searches
There exists an 8.25 inch extrusion with 3 inch fins though but that design is not what you have (and costs a bloody bomb )
 
Last edited:
magma said:
dear anilva

im not a heatsink dealer and have no commercial intrest in heatsinks

it just that my business has me heavily invested in Aluminium extrusions and so i come in contact with all kinds of extrusions that includes sinks too
and hence sometimes know heatsink manufacturers as well

it was them who explained that fins should always be vertical.
they showed me softwares and explained how the sink actually works and how they caluculate sink requirements
what are the effects if fins are placement horizontal

SINKS are classified according to their width because it is this width which is mounted
For e.g yours is an 8 inch extrusion


what matters most is the thickness of the base and the length of the fins and ofcourse the no. of fins

the pic ive posted is of a 10 inch extrusion
16mm base
82mm fin height

what you can try and do is mount the sink so that the fins are vertical ( like how i have posted in my pic )
yes for an 8 inch extrusion the height youve got is 12 inches which would make the amp an ODD 12 inches high

what you can try is see if you can cut it at 6 inches and load both extrusions side by side for a 16 inch breadth
Of course you need to have a nice way of brazing the pieces together with pure AL ingot
you amp will then be 16 inches deep and 6 inches high

Ideally you require longer fins though
Are you sure those are 2.5 inch fins? looks closer to 1.5 inch
i havent come across such an extrusion ( 8 inch with 2.5 inch fins!) in my searches
There exists an 8.25 inch extrusion with 3 inch fins though but that design is not what you have (and costs a bloody bomb )
Click to expand...

Thanks for the explanation. I stand corrected. Each heatsink is 1.5" fins (and not 2.5"), 8" width and 12" length.

If you have access to better heatsinks including the dimensions you mentioned with vertical fins, I would be most happy to buy it. I am not saying you are in the heatsink business, but you happen to know someone who sells it, I do not mind.

Thanks
 
F5 playing music

Finally, the amp is connected to some old speakers and a CD player through Yamaha preamp.

Playing wonderfully. Zero audible distortion, semiconductor noise and hum. I cannot hear anything other than music. Difficult to find out if the amp is on or off if there is no music input.

Will play for another 2 hours and if nothing untoward happens will connect to my Fostex fullranges.

Cheers.
 
Re: F5 playing music

anilva said:
Finally, the amp is connected to some old speakers and a CD player through Yamaha preamp.

Playing wonderfully. Zero audible distortion, semiconductor noise and hum. I cannot hear anything other than music. Difficult to find out if the amp is on or off if there is no music input.

Will play for another 2 hours and if nothing untoward happens will connect to my Fostex fullranges.

Cheers.
Click to expand...

excellent !
Now be prepared for a flurry of questions for help from forum members !:)
 
anilva,

Is the amp Class A or Class AB. what is the max poweroutput of the amp. How much did you end up spending for.

Thanks
pandu
 
pdhanwada said:
anilva,

Is the amp Class A or Class AB. what is the max poweroutput of the amp. How much did you end up spending for.

Thanks
pandu
Click to expand...

25 watts Class A per channel. I spent a lot for buying various other things for long term. But just the amp is under 15K, including PCB, parts, Toroid, Heatsinks....

My advice is that if you have not done DIY electronics before, this is not your first project. Also if you do not know soldering, learn it or stay away from DIY.
 
Re: F5 playing music

anilva said:
No problem. Any number of questions are OK with me. I am waiting for your reply on heatsinks.
Click to expand...

are you serious about the sinks?!
i thought since youve already pumped in enough on that amp you would not want to plough in more

dear sir
yes i do have access to probably all heatsinks availble in the market today and many that are not availble for free sale too ( these are probably for export only or exclusive sections meant only for 1 client/manufacturer
)
yes some are difficult to get and some cannot be bought in retail quantaties since i buy from the extruder directly(NO dealer/no manufacturer)

Due to this i have to buy the entire extrusion length of 6 feet
Hence group buys would turn out cheaper for all

Currently im working on a couple builds wherein i have had to procure 6 feet long CUSTOMIZED extrusion for my purpose
Check my Chasis build thread for pics
http://www.hifivision.com/diy/12016-amp-enclosures-chasis-cabinets-9.html

i also have access to the 10 inch extrusion with 82mm fins whose pic i posted earlier

But make no mistake these are customised extrusions made by HINDALCO india
and will be expensive

Also note : I will not bother to get extrusions that are readily available.
This is because i do not want to get in favours (from my vendors)for something which you guys can buy from the market.

There is also superb extrusion(that even rivals Nelsons) that has been customised for an exclusive client.
But as i said earlier i would have to buy off the entire extusion lenght
cost of a 6 foot piece - a cool 25K !
specs - 8.25inch extrusion which can be cut at any length reqd
16mm thick base
75mmlong fins

All please note : i say again - i am no dealer or have commercial intrests
I am just fortunate that My current business allows me access to many extrusions
The sole purpose would be helping members source something they cant-there is no other purpose
Mods can shut me down if something is amiss
 
Last edited:
Re: F5 playing music

magma said:
are you serious about the sinks?!
i thought since youve already pumped in enough on that amp you would not want to plough in more

dear sir
yes i do have access to probably all heatsinks availble in the market today and many that are not availble for free sale too ( these are probably for export only or exclusive sections meant only for 1 client/manufacturer
)
yes some are difficult to get and some cannot be bought in retail quantaties since i buy from the extruder directly(NO dealer/no manufacturer)

Due to this i have to buy the entire extrusion length of 6 feet
Hence group buys would turn out cheaper for all

Currently im working on a couple builds wherein i have had to procure 6 feet long CUSTOMIZED extrusion for my purpose
Check my Chasis build thread for pics

i also have access to the 10 inch extrusion with 82mm fins whose pic i posted earlier

But make no mistake these are customised extrusions made by HINDALCO india
and will be expensive

Also note : I will not bother to get extrusions that are readily available.
This is because i do not want to get in favours (from my vendors)for something which you guys can buy from the market.

There is also superb extrusion(that even rivals Nelsons) that has been customised for an exclusive client.
But as i said earlier i would have to buy off the entire extusion lenght
cost of a 6 foot piece - a cool 25K !
specs - 8.25inch extrusion which can be cut at any length reqd
16mm thick base
75mmlong fins

All please note : i say again - i am no dealer or have commercial intrests
I am just fortunate that My current business allows me access to many extrusions
The sole purpose would be helping members source something they cant-there is no other purpose
Mods can shut me down if something is amiss
Click to expand...

I am serious. Sent a PM.
 
I want heatsink too. One set for F5 and one tiny set for the GC.

and yes I am serious too. :)

Cheers
 
gobble said:
Magma ,
For you. How smooth is the surface? I actually need one with a flange. Have you heard of Afcoset in Mumbai?

Cheers
Click to expand...

i have replied in my thread
please move all discussions there so as not to disrupt continuity of Anilvas thread here
 
Last edited:
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