BPA300 Round 2

[shmulik]

Originally Posted by toufu

I completed mine, and I am getting a little high frequency hiss and noise, is that what you are talking about?

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.

[Naturlyd]

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?

Originally Posted by shmulik

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.

[regiregi22]

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

[toufu]

look for them on ebay. under 3 x lm3886.

[AlanElsdon]

Originally Posted by regiregi22

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

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

[viki_v2]

hi guys,
regarding pa150 board if you guys need it i have 4 boards pa 150=drv134, and i can get other made if needed, but minimum quantity is 20 pcs

[jack.]

I have 16 boards and all of the components, but I was planning on going the audio transformer route so I did not buy the inverter or solen input caps. If anyone is interested respond here

LM3886's, components and PCBs for BPA300

[regiregi22]

Originally Posted by AlanElsdon

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

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

[regiregi22]

Hi, I have a question regarding first power up. Is there a preferable position of the dc tunning trimmers, like 0 ohms, 50kohms or the middle position?

Regards,
Regi

[toufu]

Originally Posted by regiregi22

Hi, I have a question regarding first power up. Is there a preferable position of the dc tunning trimmers, like 0 ohms, 50kohms or the middle position?

Regards,
Regi

I don't think it matters, at least in my case.