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Old 2nd August 2018, 09:58 AM   #2681
Zen Mod is offline Zen Mod  Serbia
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Aleph-X builder's thread.
best are the ones having least amount of interelectrode capacitance .... but cheapest ones are even better

it really depends of your intention - how many you want to put in each quadrant

if you prefer small number , IRFP150 is best choice , as I wrote

with little luck , you don't even need to match them , if staying with just one per quadrant

however , if you intend to feed speakers with less than nice modul of impedance , there is no replacement for displacement , as our friends from hot rod department use to say

X is bridged amp , each half seeing just half of load ..... so number of outputs is what is giving you muscles
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Old 2nd August 2018, 12:16 PM   #2682
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So to double the output, the number of fet's quadruples?
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Old 2nd August 2018, 01:12 PM   #2683
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Aleph-X builder's thread.
dunno

4 quadrants ......

go figure
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Old 2nd August 2018, 01:49 PM   #2684
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dunno

4 quadrants ......

go figure


Duhu :-)
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Old 5th August 2018, 12:41 AM   #2685
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Quote:
Originally Posted by Zen Mod View Post
no less than 2 mosfets per quadrant , so 8 per channel

only in case that you use IRFP150 , practically 2pcs of IRFP240 in one case , you can go with 1 per quadrant
Disagree. My Aleph-X monoblocks use 4 IRFP044’s with 15V rails and 2.5A bias per device, and have been in heavy use for around 10 years. It’s a matter of heat sinking. Remember, Nelson Pass tells us that Mosfets get more linear in response with higher bias right up until the magic smoke is released. The downside is that less devices results in lower damping factor, but with the aleph current source creating a sort of negative output impedance effect, the impact of the fewer devices is somewhat mitigated.

For guidance on where the boundaries are for per device power dissipation see Transistor Dissipation and Turbo Projects

Terry
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Last edited by metalman; 5th August 2018 at 12:51 AM.
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Old 5th August 2018, 01:59 AM   #2686
Zen Mod is offline Zen Mod  Serbia
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oh yeah Terry ........ you can go whichever way you want , with enough experience ..... but you don't want a novice to burn his fingers on first proper amp project ?

besides , comparing IRFP044 with IRFP240 is ........ something as cheating

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Old 8th August 2018, 02:16 AM   #2687
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Aleph-X builder's thread.
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Originally Posted by Flushing Shadow View Post
I’m looking for the BOM for the original pcb, can’t seem to find any info in the wiki or am i just looking in the wrong corner?
Even when I'm not on vacation, Zen usually beats me to the punch. Have a look at my webpage for the Aleph-X amp - link is in my signature. I have the BOM for original 15v version as well as for the higher powered 22v version. Just about all of the information you need is there, though it's a little messy as the page evolved over a period of 7-10 years...

I also have a copy of the original wiki for this amp on my web page.
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Old 8th August 2018, 09:43 AM   #2688
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Thanks! I allready found your page and i am soaking up the info!
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