I read through the document and it is still unclear. In the document the suggested values for R32 is 2kohm and R33 / R34 is 120ohm which matches the BOM "description" in the protection board PDF document as well.
Alexis has provided different values as part of his group buy (2.7kohm for R32 and 300ohm for R33/R34). I am assuming the values provided in his kit are also valid. From what I read in the document, these higher values will result in slightly less sensitive trigger behavior during DC fault detection.
Is my understanding accurate?
Thanks!
Greg,
See post #474.
Nic used the Alexis values and his did not trigger.
Markus tested the new values with a full analog curve trace and it behaves as predicted.
So use the new values.
It is still on the to-do list of WK to get resistors and send to the local distributors.
He is, however, off for 3 weeks for personal reasons.
I think it is best to send those with the regulator heat sink sets.
But SMD resistors cost less than 10 cent each, and there is no reason to use special ones here.
So please go ahead and buy some from your local electronic shop.
I owe you one on this.
Patrick
See post #474.
Nic used the Alexis values and his did not trigger.
Markus tested the new values with a full analog curve trace and it behaves as predicted.
So use the new values.
It is still on the to-do list of WK to get resistors and send to the local distributors.
He is, however, off for 3 weeks for personal reasons.
I think it is best to send those with the regulator heat sink sets.
But SMD resistors cost less than 10 cent each, and there is no reason to use special ones here.
So please go ahead and buy some from your local electronic shop.
I owe you one on this.
Patrick
As promised, be it somewhat late, here is a simple test procedure for the protection board :
http://xen-audio.com/documents/f5x/130603 Protection Board F5X Test.pdf
You should make the PCB repair as already posted by ashaw for Batch 1 protection boards.
You should also change the resistor values explained above on post #601, 602.
You should then, AFAIK, have no problem getting the protection board to work as designed.
Patrick
http://xen-audio.com/documents/f5x/130603 Protection Board F5X Test.pdf
You should make the PCB repair as already posted by ashaw for Batch 1 protection boards.
You should also change the resistor values explained above on post #601, 602.
You should then, AFAIK, have no problem getting the protection board to work as designed.
Patrick
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We'll organise something to send you in the next few days.
The assembly and set up procedure is exactly like what fitzfish has described in the beginning of this thread.
So we are not going to repeat those and only send those that have been revised.
Those include the component numbering and the Bill of Material.
The circuit remains unchanged since alomst 8 years.
Patrick
The assembly and set up procedure is exactly like what fitzfish has described in the beginning of this thread.
So we are not going to repeat those and only send those that have been revised.
Those include the component numbering and the Bill of Material.
The circuit remains unchanged since alomst 8 years.
Patrick
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VS-15ETH06FPPBF
VS-15ETH06FPPBF Vishay Semiconductors | Mouser
http://www.mouser.com/ds/2/427/15eth06p-87399.pdf
There is a 30A version, but it doesn't come in an isolated tab package.
Hi Patrick,
Finally with full load the voltage after CRC is 18.1V.
A dumb question, I don't have clear what is the right polarisation current per device. Now I have 333mV across the 0R22 resistor (Measured after two hours) (1.5A per device / 6A per channel). I read on the thread that the right value is 2A per mosfet. But with 1,5A my amp is hotter than hell
. (6 seconds by hand test, ambient temperature 32 Cº) (The top panel is much hotter that the heatsinks).
Am I wrong?
Thanks!
Finally with full load the voltage after CRC is 18.1V.
A dumb question, I don't have clear what is the right polarisation current per device. Now I have 333mV across the 0R22 resistor (Measured after two hours) (1.5A per device / 6A per channel). I read on the thread that the right value is 2A per mosfet. But with 1,5A my amp is hotter than hell
. (6 seconds by hand test, ambient temperature 32 Cº) (The top panel is much hotter that the heatsinks). Am I wrong?
Thanks!
I'm sorry, I probably would not have explained well. I left every mosfet at 1.5A, 333mV across the 0R22 resistor. 4x 1.5A per channel (A F5X channel have 4 x fets, two for F5 side) Am I wrong?
Wrong.
The bias current passes through both mosfets on one side in series.
It's the same current in the N & P fets.
The other side does the same.
That way your total bias for the two halves of the balanced amplifier is two times 1.5A = 3A of bias current.
If you now add the right and left channels toether you will have the PSU supplying a total current of 6A IF you only had ONE transformer.
Each transformer supplies 3A.
In a standard F5X build the current is 4A.
All the fets were measured and selected for this 4A of current (2A through each FET).
The bias current passes through both mosfets on one side in series.
It's the same current in the N & P fets.
The other side does the same.
That way your total bias for the two halves of the balanced amplifier is two times 1.5A = 3A of bias current.
If you now add the right and left channels toether you will have the PSU supplying a total current of 6A IF you only had ONE transformer.
Each transformer supplies 3A.
In a standard F5X build the current is 4A.
All the fets were measured and selected for this 4A of current (2A through each FET).