I'm sorry but what's the problem? I mean, what do you expect it to sound like when it clips? I'd say a good crackle is normal. Add clip protection or don't drive it that hard? If it comes out of clipping OK and survives I'd say good job.
Thanks for suggestion Pierre!
I think I found the problem.
The others side of 10k resistor (R7) on the SD pin is connencted to the COM pin on the PCB.
Later I removed that resistor and connected it directly. But that was wrong, because the SD pin is referred to the Vss.
So, when I shorted the resistor (R3) between Vss and COM, that crackle disappeared.
That crackle before was not normal. Lets say, that was something like blatter.
I only wanted it to crackle like a class AB amp (or at least similar to it).
I dont want to add clip protection unless I have to.
I think I found the problem.
The others side of 10k resistor (R7) on the SD pin is connencted to the COM pin on the PCB.
Later I removed that resistor and connected it directly. But that was wrong, because the SD pin is referred to the Vss.
So, when I shorted the resistor (R3) between Vss and COM, that crackle disappeared.
That crackle before was not normal. Lets say, that was something like blatter.
I only wanted it to crackle like a class AB amp (or at least similar to it).
I dont want to add clip protection unless I have to.
Has there been any results on this from IR
Seems to run at a high frequency, self oscillation, not sure on how its done.
http://www.irf.com/technical-info/refdesigns/iraudamp1.pdf
Seems to run at a high frequency, self oscillation, not sure on how its done.
http://www.irf.com/technical-info/refdesigns/iraudamp1.pdf
Here you can find designing of a BCA amp with schematics:
it has NO dead time!-> minimal THD
http://www.diyaudio.com/forums/show...&threadid=94263
it has NO dead time!-> minimal THD
http://www.diyaudio.com/forums/show...&threadid=94263
It has always intrigued me why the designers of these amps choose such ridiculous values for some of the components -- on the 'main' pcb R246 is shown as a variable 10K resistor - and R245 is shown as 5.11K in series with it.
5.11K in series with a variable resistor! 😕
I wonder how much else doesn't actually need to be there 🙂
5.11K in series with a variable resistor! 😕
I wonder how much else doesn't actually need to be there 🙂
One reason the 5.11k could be chosen because the lower tolerance may also have better temperature stability.
Are you wondering why there is a series resistor or why it is 5.11k ? There is a logical explanation for both of course. But before I give you the answer I let you think a little more !! 😉
Regards
Charles
Unfortunately I don't seem to be able to access the schematic again at the moment, but from what I recall the variable resistor enabled the adjustment of a 'monitor' of some sort.
What I don't understand is why it is necessary to be able to vary between 5.11K (+ the tolerance of the minimum pot position) and 15.11K (+ the tolerance of the pot end position).
If the adjustment is likely to be around the variable resistance centre point, and within a range that is reasonably 'easy' to calibrate, then I would have thought 4K7 would have been perfectly adequate.
If you need to calibrate to within 10R (the present resistor is shown to 3 decimal places) how on earth do you 'tweak' a variable to that degree of accuracy (20 turn device?)
And why? -- if your design is that fragile, you've probably got it wrong!
Heaven knows what happens if the ambient temperature changes!!
I've obviously missed the point somewhere here! 🙂
What I don't understand is why it is necessary to be able to vary between 5.11K (+ the tolerance of the minimum pot position) and 15.11K (+ the tolerance of the pot end position).
If the adjustment is likely to be around the variable resistance centre point, and within a range that is reasonably 'easy' to calibrate, then I would have thought 4K7 would have been perfectly adequate.
If you need to calibrate to within 10R (the present resistor is shown to 3 decimal places) how on earth do you 'tweak' a variable to that degree of accuracy (20 turn device?)
And why? -- if your design is that fragile, you've probably got it wrong!
Heaven knows what happens if the ambient temperature changes!!
I've obviously missed the point somewhere here! 🙂
Depending on which series of resistors you use (and you better use what your company is using by default !) there is neither a 4.7k nor a 5.1 k resistor available if you want to achieve a tuning range of 5 to 15 k. So the nearest value is 5.11k !!!!
Simple as that !
Regards
Charles
Simple as that !
Regards
Charles
At my end of the pecking order, the purchasing people moan if they have to stock E24 values, let alone E 48, 96 or 192!!
And if I presented a design that could not accept a 4K7 to 14K7 range instead of a 5K to 15K range it would be thrown straight back at me as 'too fussy' !
Now if I worked a little higher up the scale---- 🙂
And if I presented a design that could not accept a 4K7 to 14K7 range instead of a 5K to 15K range it would be thrown straight back at me as 'too fussy' !
Now if I worked a little higher up the scale---- 🙂
Good day Sergio.
Could you send me the final files?
Thank you.
luizcpimenta@yahoo.com.br
luizcpimenta@gmail.com
Hi fehrudi,
not using SD then replace R7(10K) with jumber and R3(10R) not required short that point with jumber. cracking sound b'cause of SD point not good.
Regards
MANOJ
not using SD then replace R7(10K) with jumber and R3(10R) not required short that point with jumber. cracking sound b'cause of SD point not good.
Regards
MANOJ
merry CHRISTmass to you all - Status
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