Just brilliant bit-by-bit going trough each aspect with fine combed.
Rod site is really good and easy to understand tanks for the find.
Udailey as you posted the data
What is the heat propagation on different metals meaning how easy is for heath to travel across
I think that Cooper is about 2 times as good as aluminium but I may be wrong could you help.
I was looking at mounting options and I am going to try something similar to the picture
Posted
Rod site is really good and easy to understand tanks for the find.
Udailey as you posted the data
What is the heat propagation on different metals meaning how easy is for heath to travel across
I think that Cooper is about 2 times as good as aluminium but I may be wrong could you help.
I was looking at mounting options and I am going to try something similar to the picture
Posted
Attachments
The Specs for ParMetal are at the bottom of the page.
When I called them they said that the data there was measured data, not theoretical. The quote it in C/W/inch.
Also if I'm reading Udaily right, I should paint the heatsink with black oil? Wow. I didn't know that. When I called Par-Metal they had the option of anodizing...
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I haven't finished it yet but I bought 2 twelve inch pieces of the Heatsink USA 10 inch profile for my F5. Maybe more than I need. It's pretty hefty stuff at about 12 pounds each. Better too much than not enough. Also looks a bit nicer in person than it does on his website. Made in USA too. Not sure about Par-metal.
Not black oil but an oil based paint that is black. Well, thats Rod's information.. I just spit it back out here. He says black oil paint very very thin is the best but that anodizing is good to, you can see on his graphs. I would go for the anodizing option but then again you would still be buying a sink that cant compete with HS USA sinks. Honestly in the USA the HS USA guys have the best deal that I can find and the extrusion is made, in my opinion, especially for Pass DIY efforts. Its just my guess but I am betting Russel started his business to take care of us.
Copper spreads the heat the fastest but it doesnt like to LET GO of the heat. Aluminum spreads it pretty fast as well AND dissipates. Aluminum is best in a sink. You want to use a heat spreader? Probably copper is best but I would use some sort of thermal paste to help get the heat from the copper over to the aluminum and you will find folks telling you that copper on top of aluminum causes some sort of chemical reaction and I forget what else happens but two odd metals touching for a long time has some chemical reaction that has been discussed here before. I think if you use the paste you might not worry so much about this reaction.
Uriah
Edit: Oooooh we are creeping up on 10,000 posts!
Copper spreads the heat the fastest but it doesnt like to LET GO of the heat. Aluminum spreads it pretty fast as well AND dissipates. Aluminum is best in a sink. You want to use a heat spreader? Probably copper is best but I would use some sort of thermal paste to help get the heat from the copper over to the aluminum and you will find folks telling you that copper on top of aluminum causes some sort of chemical reaction and I forget what else happens but two odd metals touching for a long time has some chemical reaction that has been discussed here before. I think if you use the paste you might not worry so much about this reaction.
Uriah
Edit: Oooooh we are creeping up on 10,000 posts!
Tanks udailey
2 different metals in contact chem reaction very good point and need looking at.
Yes heath spreaders it will be.
As 4 ohms speakers loads off currants.
Heath sink I have found this new product in Farnell 1315296
Graphite based so is conductive eletricaly good enoug between sinks and heath spreaders not so on the mosfets.
Thermal conductivity 10.5 W/mK what ever that means.
And red Kerafoll
While here could you help with speakers protection?
To fix a broken amp no problem
to replace speakers money and no music for a while. I could survive that.
To have her say I told you so priceless.
Options are quite a few
Fuses but signall degradation and slow
There is a few around based on low pass filters (nuisance tripping) and there use to be a few dedicated IC now obsollete so ..
I was thinking as AC signall by its nature crosses the zero line voltagge to make a detector that (say ipoteticalicamente Just positive side for semplicity)
Rising edge start a timing circuit when signal return to zero reset the timer
IF there is DC offset or one of the mosfets blow the signal will stay hi and the timer will latch and operate a relay disconecting the speakers same for negative branch.
But relay are not so good with DC as arking between contacts and also compromise signall when connected in series with the speakers
Ten maybe a Mosfet operated as swithc after the capacitors bank when the circuit detect a fault it will stop conducting disconnecting the suply.
Much faster than a relay.
I am stuck with the timing circuit as maybe it need to be 100 or maybe 20 milly seconds
question about mosfet
What is the heat load / disipation for mosfets as switch (saturation region)
I believe it is much less than when in the linear region as in saturation region resistance seen is much lower?
If so It may be possible then to use one as swithc with say full rail voltagge at say 3 / 4
A and use this to disconnect the suply to the amplifier after the capacitor banks.
Help please.
2 different metals in contact chem reaction very good point and need looking at.
Yes heath spreaders it will be.
As 4 ohms speakers loads off currants.
Heath sink I have found this new product in Farnell 1315296
Graphite based so is conductive eletricaly good enoug between sinks and heath spreaders not so on the mosfets.
Thermal conductivity 10.5 W/mK what ever that means.
And red Kerafoll
While here could you help with speakers protection?
To fix a broken amp no problem
to replace speakers money and no music for a while. I could survive that.
To have her say I told you so priceless.
Options are quite a few
Fuses but signall degradation and slow
There is a few around based on low pass filters (nuisance tripping) and there use to be a few dedicated IC now obsollete so ..
I was thinking as AC signall by its nature crosses the zero line voltagge to make a detector that (say ipoteticalicamente Just positive side for semplicity)
Rising edge start a timing circuit when signal return to zero reset the timer
IF there is DC offset or one of the mosfets blow the signal will stay hi and the timer will latch and operate a relay disconecting the speakers same for negative branch.
But relay are not so good with DC as arking between contacts and also compromise signall when connected in series with the speakers
Ten maybe a Mosfet operated as swithc after the capacitors bank when the circuit detect a fault it will stop conducting disconnecting the suply.
Much faster than a relay.
I am stuck with the timing circuit as maybe it need to be 100 or maybe 20 milly seconds
question about mosfet
What is the heat load / disipation for mosfets as switch (saturation region)
I believe it is much less than when in the linear region as in saturation region resistance seen is much lower?
If so It may be possible then to use one as swithc with say full rail voltagge at say 3 / 4
A and use this to disconnect the suply to the amplifier after the capacitor banks.
Help please.
that is not Rth s-a.
Rth s-a in C/W is not inversely proportional to the height of the heatsink.
The numbers quoted at the bottom are nonsense.
I know there are people who remove the current limiting and say that the amp sounds wonderful, the gods speak, angels kiss you, etc...
I, personally, am going to build mine as designed, get it up and working properly, burnt in and happy. Then, and only then will I try it without the current limiting.
I, personally, am going to build mine as designed, get it up and working properly, burnt in and happy. Then, and only then will I try it without the current limiting.
I'd say there are four different locations for a speaker protection circuit to be chosen.
In the output lead after the amplifier.
In the supply rails to the amplifier, but after the main energy store of the smoothing capacitors.
At the input to the amplifier.
Intrinsic to the circuit of the amplifier.
Any of these locations could be made to work for some of the fault scenarios that the speaker needs to be protected from. I don't think any one location satisfies the protection duty for all fault scenarios.
I think you need to mix and match to protect against the high risk scenarios.
I like input muting, cheap and easy and overcomes source faults. But it must latch for as long as the fault exists.
I like rail fuses, cheap and easy and does protect from long term almost DC output currents.
I like VI limiting, not so cheap and not so easy, but can prevent destruction of parts of the output stage.
But I am inclined to think that all these three together do not protect against all the high risks. Something else is needed, an output relay or output crowbar or? Preferably not an output fuse, neither outwith the global loop, nor within the Global loop.
In the output lead after the amplifier.
In the supply rails to the amplifier, but after the main energy store of the smoothing capacitors.
At the input to the amplifier.
Intrinsic to the circuit of the amplifier.
Any of these locations could be made to work for some of the fault scenarios that the speaker needs to be protected from. I don't think any one location satisfies the protection duty for all fault scenarios.
I think you need to mix and match to protect against the high risk scenarios.
I like input muting, cheap and easy and overcomes source faults. But it must latch for as long as the fault exists.
I like rail fuses, cheap and easy and does protect from long term almost DC output currents.
I like VI limiting, not so cheap and not so easy, but can prevent destruction of parts of the output stage.
But I am inclined to think that all these three together do not protect against all the high risks. Something else is needed, an output relay or output crowbar or? Preferably not an output fuse, neither outwith the global loop, nor within the Global loop.
Both techniques are good. Look, again, here ESP - Heatsink design and transistor mounting
Notice that you should pay close attention that when you drill your hole in the heatsink you should also countersink a tiny bit to remove the upheaval of the aluminum.
Uriah
My F5 has been working just fine(about 1 1/2 yrs.) with alum channel securing the fets, as seen here DSCN3798 - My Photo Gallery
jim
I think that Andrew has a couple good suggestions. Of course he does and he knows much more than me. For protection I like his idea of input signal to ground and I like output of power supply interrupted. Could this pass over a transistor and then just turn transistor off in a short? This depends on the transistor's 'on resistance.' The transistor will run hot and we already have a lot of heat. Perhaps two relay positions. Relay after power caps to remove power to the amp, but dont remove power from protection circuit .... and relay to mute by sending signal to ground.
Uriah
Uriah