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BPA300 Round 2

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shmulik

Member
Joined 2004
toufu said:
I completed mine, and I am getting a little high frequency hiss and noise, is that what you are talking about?
Click to expand...

No. I connected a signal generator on the input and oscilloscope on the output (in parallel to 8 Ohms power resistor) and played sine and square waves. With the sine wave I measure the amplitude while raising the frequency and watch its magnitude. I want the amplitude in a fixed value as a function of frequency for high enough frequency (well above 20KHz). with the square wave I just examine the form of the wave. in my case it rings - has decaying oscillations right after the fast rising (or falling) edge. if I increase the feedback capacitor this ringing is weakens but the frequency response suffers.

both effects influence the sound quality of the amplifier. you get either boomy bass or lack of spice and attack.

Alex reports excellent measurements. therefore I suspect I did something wrong, either while building the modules or in their installation. I'm working now on insulating the problem but with no results yet. if others have measurements it may hint me where is the fault in mine.
 
N

Naturlyd

Member
Joined 2010
Still measuring/sounding badly?

Your post made me curious as I`m picking up a set of boards for the BPA300 tomorrow.

Did you make your own boards/where did you buy them?

Did you follow the original BOM?



shmulik said:
No. I connected a signal generator on the input and oscilloscope on the output (in parallel to 8 Ohms power resistor) and played sine and square waves. With the sine wave I measure the amplitude while raising the frequency and watch its magnitude. I want the amplitude in a fixed value as a function of frequency for high enough frequency (well above 20KHz). with the square wave I just examine the form of the wave. in my case it rings - has decaying oscillations right after the fast rising (or falling) edge. if I increase the feedback capacitor this ringing is weakens but the frequency response suffers.

both effects influence the sound quality of the amplifier. you get either boomy bass or lack of spice and attack.

Alex reports excellent measurements. therefore I suspect I did something wrong, either while building the modules or in their installation. I'm working now on insulating the problem but with no results yet. if others have measurements it may hint me where is the fault in mine.
Click to expand...
 
A

AlanElsdon

Member
Joined 2003
Boards for BPA300

regiregi22 said:
Anybody knows some place to get some of these boards or other similar ones? I have seen some websites, but they currently don't carry them.
I can take as a good suggestion to propose other board with a variation in the amount of devices, etc.

Thanks,
Regards
Click to expand...

Hi

I have a set of boards from the P-A Sjostrom - 4 x PA150 boards plus 2 x DRV Balanced Driver boards plus 2 x DRV ICs plus all SMD parts for the PA150 boards. The DRV boards are the ones which had X4/X2/X3 mis-labled.

I am unlikely to ever build the amps - so open to offers.

Alan
 
regiregi22

regiregi22

Member
Joined 2009
haciendodelpunkunaamenaza.blogspot.com
AlanElsdon said:
Hi

I have a set of boards from the P-A Sjostrom - 4 x PA150 boards plus 2 x DRV Balanced Driver boards plus 2 x DRV ICs plus all SMD parts for the PA150 boards. The DRV boards are the ones which had X4/X2/X3 mis-labled.

I am unlikely to ever build the amps - so open to offers.

Alan
Click to expand...

I sent you a PM. Send me one with an orientative price. I have already ordered the DRV134 boards from P-A, so I am not really interested in them. Can I assume that the smd resistors are 0.1%?
Neither of them are a problem if you really want to sell the whole as a kit.

Regards,
Regi
 
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