Sinks
Yep eight weeks.............go to the Conrad Web site....and select what you need...........the 350x150x40 is quite good value....last worked out at £29.00 each....
Be carefull..........I didn't order quite enough I am ordering an extra 350x50 sinks to up my thermal transfer...........
MF35 Series
Product Code Standard Lengths
in mm Thermal Resistance
C/Watt for 80 °C rise Weight
in kg. 0.21
code:- MF35-151.5
Yep eight weeks.............go to the Conrad Web site....and select what you need...........the 350x150x40 is quite good value....last worked out at £29.00 each....
Be carefull..........I didn't order quite enough I am ordering an extra 350x50 sinks to up my thermal transfer...........
MF35 Series
Product Code Standard Lengths
in mm Thermal Resistance
C/Watt for 80 °C rise Weight
in kg. 0.21
code:- MF35-151.5
Sinks
The value is for the sink.........see posted page below....
My space is tight as well..........take a look at my monoblock design....posted earlier......
http://www.conradheatsinks.com/products/flat100_350.html#MF35
I don't think you will get much smaller.........if you do the heat build up will be huge..........I am using a 'u' chassis to assist in heat transfer arround the perimeter............this will be 8mm thick!
+ I am using mild fan assistance........from 'panaflow fans....4 per amp......these are vertually silent.
Don't forget your Traffo,regulator, resistors, main board and caps will probably emitt arount 50-65watts of heat.....right in the core of the amp......these Aleph's are mean suckers.....
ps are your Traffo's in good nick....Magura has had problems...
The value is for the sink.........see posted page below....
My space is tight as well..........take a look at my monoblock design....posted earlier......
http://www.conradheatsinks.com/products/flat100_350.html#MF35
I don't think you will get much smaller.........if you do the heat build up will be huge..........I am using a 'u' chassis to assist in heat transfer arround the perimeter............this will be 8mm thick!
+ I am using mild fan assistance........from 'panaflow fans....4 per amp......these are vertually silent.
Don't forget your Traffo,regulator, resistors, main board and caps will probably emitt arount 50-65watts of heat.....right in the core of the amp......these Aleph's are mean suckers.....
ps are your Traffo's in good nick....Magura has had problems...
Hi
I was also going to go with D3s spec of 8A bias but what i am going to do now is start with a lower bias and work my way up as high as I can go without cooking anything with my current heatsinks, I will try to do this before the 8 weeks is up so if i think I need the extra bias i will order the extra sinks.
Regarding the power supply, would using 2 of Bigparsnips rectifiers (one for +ve rail, one for-ve rail) bring the voltage down even more than using one would? actually i dont think it would.
Mark.
PS my transformers are fine.
I was also going to go with D3s spec of 8A bias but what i am going to do now is start with a lower bias and work my way up as high as I can go without cooking anything with my current heatsinks, I will try to do this before the 8 weeks is up so if i think I need the extra bias i will order the extra sinks.
Regarding the power supply, would using 2 of Bigparsnips rectifiers (one for +ve rail, one for-ve rail) bring the voltage down even more than using one would? actually i dont think it would.
Mark.
PS my transformers are fine.
Sinks
With say 20v and 8a bias......and with the sinks you have.....
you will have in the region of 90deg....ouch!!!!
You will probably looking at around 4a bias........keep the same no fets..........then up the bias later once you have better cooling.
My amps are turning into monsters.....aluminium chassis work is not cheap!!!
With say 20v and 8a bias......and with the sinks you have.....
you will have in the region of 90deg....ouch!!!!
You will probably looking at around 4a bias........keep the same no fets..........then up the bias later once you have better cooling.
My amps are turning into monsters.....aluminium chassis work is not cheap!!!
Kram said:
Hi, if you do use two board for the supply (ie one for each secondary winding then conect the comon ground after this) you will indeed lose a bit more supply voltage, as you will have double the number of diode drops in there (so instead of having one per rail as you would have with the siingle rectifier, you will get two per rail insted, and so lose an extra 0.5 - 1 V per rail)
And richard, if you think your chasis is going to be a squeeze, just think how mcuh fun it should be for me tying to fit my mono blocks into a case more than half the height of yours (the internal space will measure only 330 x 345 x 69 mm, only just enough height for me to squeeze in my supply caps on their sides).
Bleeder Resistors:
I think I am going to use a CRC PSU network. The R will be around 0.47Ohms. As discussed elsewhere, my main caps are 25V, and although I doubt there will be any harm if run at 26V, I would rather be safe than sorry. If the load (Aleph-X board) is removed, the PSU jumps from ~19V to ~26V. I had forgotten that I will need bleeder resistors to drain the caps. Won't this lower the output Voltage when used in conjuntion of the CRC network?
P.S.
I want to enter into the "most crammed Aleph-X" competition...
http://www.diyaudio.com/forums/showthread.php?postid=382726#post382726
Gaz
I think I am going to use a CRC PSU network. The R will be around 0.47Ohms. As discussed elsewhere, my main caps are 25V, and although I doubt there will be any harm if run at 26V, I would rather be safe than sorry. If the load (Aleph-X board) is removed, the PSU jumps from ~19V to ~26V. I had forgotten that I will need bleeder resistors to drain the caps. Won't this lower the output Voltage when used in conjuntion of the CRC network?
P.S.
I want to enter into the "most crammed Aleph-X" competition...
http://www.diyaudio.com/forums/showthread.php?postid=382726#post382726
Gaz
Rarkov said:
For the bleeder resisrtors to keep the output at the same level when the circuit is not conected, you would need to be drawing the exact smae current through them as the actual board. So, unless you want to have some very big bleeder resisrtors letting 8A or so straight through to ground all the time (and dissipating just as much power as you amp), I don't think that this will help you here.
Generaly, you would only have the bleeder resistors in there to drain the caps off, in a controlled manner, when the supply was turned off (a few tens of milliamps should suffice in most cases, although, it may need to be a bit more here as your caps are so huge).
Brian Donaldson said:
That's a good point.
BTW, I noticed that (at least in my A30), the plus and minus
rails drop off to different voltages. (One was a few volts
higher than the other, though I can't remember which one.)
I only bothered to measure it when I noticed that one
of the LED's stay on longer than the other one.
Dennis
Thump!
Hi, thanks Mr Pass for your comments.............are we talking here of a chance of getting ....... serious switch off/on thump...due to aysmitry......in discharge/charge. Or....is this likely to be a minor artifact?
Do large capacity caps make matters worse? .................
I guess it generally isn't an issue as.....I have not seen much in the way of discussion on this site........
Hi, thanks Mr Pass for your comments.............are we talking here of a chance of getting ....... serious switch off/on thump...due to aysmitry......in discharge/charge. Or....is this likely to be a minor artifact?
Do large capacity caps make matters worse? .................
I guess it generally isn't an issue as.....I have not seen much in the way of discussion on this site........
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