Hello all,
since there seems to be a lot of confusion wich version of berekening....is right Hugo (Netlist) convinced me to make a new one and was so nice to put in some links and give some comment on how to improve upon the previous versions. Thanks for this!!😀
The new one is called AlephXEvaluationsheet1 (AXE-1) and is a normal excel file.
I put some comments in (just hold your mouse on the cell you want to be explained and then you´ll see the comment)
To make thing a bit nicer I also attached my Juntion TempCalculation at the bottom (also with nice explanations🙂 ) so now there will never be any more questions like:
Are these big enough, how many fets, what source resistors, etc. etc. etc..........
Comments or question are welcome but please look at it for longer than 5 minutes before you post😉
William
since there seems to be a lot of confusion wich version of berekening....is right Hugo (Netlist) convinced me to make a new one and was so nice to put in some links and give some comment on how to improve upon the previous versions. Thanks for this!!😀
The new one is called AlephXEvaluationsheet1 (AXE-1) and is a normal excel file.
I put some comments in (just hold your mouse on the cell you want to be explained and then you´ll see the comment)
To make thing a bit nicer I also attached my Juntion TempCalculation at the bottom (also with nice explanations🙂 ) so now there will never be any more questions like:
Are these big enough, how many fets, what source resistors, etc. etc. etc..........
Comments or question are welcome but please look at it for longer than 5 minutes before you post😉
William
Very very nice, 😀 😀
This helps a lot. Also a bit in understandig whats happening in the circuit.
Great Job William!!!!!!
Nils
This helps a lot. Also a bit in understandig whats happening in the circuit.
Great Job William!!!!!!
Nils
Fantastic job William!!!
Very easy to handle and helps a lot not only to get things right but to better understand what`s going on!!
In particular I like the graph of output power versus load impedance - very useful!
Thanks very much!!
(hopefully one day I`ll learn also how to use Excel to make such nice things like this)
Very easy to handle and helps a lot not only to get things right but to better understand what`s going on!!
In particular I like the graph of output power versus load impedance - very useful!
Thanks very much!!
(hopefully one day I`ll learn also how to use Excel to make such nice things like this)
If all goes well, all previous links including the WIKI will be updated with this "Penultimate" version. No more confusion. 😉 Thanks to AudioFreak for that.
/Hugo 🙂
/Hugo 🙂
Awesome worksheet William!
Warning.... dumb question Alert....
How come the X-Aleph's output drops when the speaker load impedance drops? Many Amp spec sheets have double the power rating for 4 Ohms when compared to 8 Ohms.
Thank you,
-David
Warning.... dumb question Alert....
How come the X-Aleph's output drops when the speaker load impedance drops? Many Amp spec sheets have double the power rating for 4 Ohms when compared to 8 Ohms.
Thank you,
-David
It's a class A amp, so your current can never exceed the bias current (at least with AC current gain <=50%).
David,
just up the bias and the amp will double into lower impedances (untill again the current limit is reached).
You can even test 60A of bias without anything getting hot😀
and thanks for all the compliments!!!!!😎
william
P.S. I´m thankfull for any constructive critisism or ideas how to improve AXE-1. I will look at these and when there´s enough new stuff there will be an AXE-2.........
just up the bias and the amp will double into lower impedances (untill again the current limit is reached).
You can even test 60A of bias without anything getting hot😀
and thanks for all the compliments!!!!!😎
william
P.S. I´m thankfull for any constructive critisism or ideas how to improve AXE-1. I will look at these and when there´s enough new stuff there will be an AXE-2.........
Total bias question for one channel
If total bias is 4 amps for one channel. There are 4 outputs. One amp per output. The current out of the power supply shoul be 2 amps from the positive rail and 2 amps from the negative rail. So total power from the transformer should be 4 times the rail voltage. Is this correct?
If total bias is 4 amps for one channel. There are 4 outputs. One amp per output. The current out of the power supply shoul be 2 amps from the positive rail and 2 amps from the negative rail. So total power from the transformer should be 4 times the rail voltage. Is this correct?
Hello,
Congratulation for your spreadsheet.
I constructed, there are some months, 2 monophonic Aleph-X,
http://www.passdiy.com/gallery/alephx-p4.htm
The schematic is the one of Blitz slightly modified with 24 IRFP240 MosFets.
Voltage: ±31V
Bias: 8A
Power 200 Watts / 8 ohms
With AC current gain: 50%
125 watts / 4 ohms
62 watts / 2 ohms
31 watts / 1 ohm
With AC current gain: 60%
200 watts / 4 ohms
100 watts / 2ohms
50 watts / 1 ohm
On the forum, Mr. Nelson Pass says that AC current gain = 69%, it is too high
It is the particularity of these circuits, the power decrease if the impedance of the speakers decrease. I wonder if it is true with the XA200 of PassLabs. There is perhaps a trick.
On the XA-200 Owners Manual, it is written: Max Output Current: ± approx. 15 A
How to have 15A with a bias of 8 or 8,5A without overshooting 69% of ac current bias?
With my Renaissance 90 INFINITY speakers (87dB and very low impedance 1 to 2 ohms mini) in a large room, the DC protection circuit of my Aleph-X clones operate. I would need more of power on low impedance
If someone has a solution!!!
Best regards
jl.m@tele2.fr
Congratulation for your spreadsheet.
I constructed, there are some months, 2 monophonic Aleph-X,
http://www.passdiy.com/gallery/alephx-p4.htm
The schematic is the one of Blitz slightly modified with 24 IRFP240 MosFets.
Voltage: ±31V
Bias: 8A
Power 200 Watts / 8 ohms
With AC current gain: 50%
125 watts / 4 ohms
62 watts / 2 ohms
31 watts / 1 ohm
With AC current gain: 60%
200 watts / 4 ohms
100 watts / 2ohms
50 watts / 1 ohm
On the forum, Mr. Nelson Pass says that AC current gain = 69%, it is too high
It is the particularity of these circuits, the power decrease if the impedance of the speakers decrease. I wonder if it is true with the XA200 of PassLabs. There is perhaps a trick.
On the XA-200 Owners Manual, it is written: Max Output Current: ± approx. 15 A
How to have 15A with a bias of 8 or 8,5A without overshooting 69% of ac current bias?
With my Renaissance 90 INFINITY speakers (87dB and very low impedance 1 to 2 ohms mini) in a large room, the DC protection circuit of my Aleph-X clones operate. I would need more of power on low impedance
If someone has a solution!!!
Best regards
jl.m@tele2.fr
Mike,
I´m not shure I understand your question but power from the transformer is total bias multiplied by total voltage (V+ and V-).
For +10V -10V and 10A this gives 20V x 10A = 200W
This is the power that is constantly drawn.
Jlm,
there is no trick. The specs from the AX-200, 160 and the Alephs are a bit confusing. The only way to get a given peak output current is to have enough bias or to up the ac-current-gain.
The infinity is probably one of the worst loads for the Aleph (X or not) So here I would lower the voltage to 20V and up the bias the same amount so the total dissipation stays the same for example 20V, 12A 60% gives
81 watts 8ohm
162 @4Ohm
225 @2Ohm
William
I´m not shure I understand your question but power from the transformer is total bias multiplied by total voltage (V+ and V-).
For +10V -10V and 10A this gives 20V x 10A = 200W
This is the power that is constantly drawn.
Jlm,
there is no trick. The specs from the AX-200, 160 and the Alephs are a bit confusing. The only way to get a given peak output current is to have enough bias or to up the ac-current-gain.
The infinity is probably one of the worst loads for the Aleph (X or not) So here I would lower the voltage to 20V and up the bias the same amount so the total dissipation stays the same for example 20V, 12A 60% gives
81 watts 8ohm
162 @4Ohm
225 @2Ohm
William
That would be 10A in total,
how much per fet depends on the amount of fets you use,
with 4 fets it would be 5A per fet, with 8 2.5A etc. etc.
william
how much per fet depends on the amount of fets you use,
with 4 fets it would be 5A per fet, with 8 2.5A etc. etc.
william
Mike,
if you take 100 1 Ohm resistors and put them all after each other (in series),
then you take a power supply and put 100 Volts across the first and the last of the 100 resistors,
there will flow a current of 1A through each resistor,
how much is the total current now😕
100A?
or
1A?
William
if you take 100 1 Ohm resistors and put them all after each other (in series),
then you take a power supply and put 100 Volts across the first and the last of the 100 resistors,
there will flow a current of 1A through each resistor,
how much is the total current now😕
100A?
or
1A?
William
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