BPA300 mono block finished and measured

[peranders]

Impressive but notice that the fundamental tone is under 0 dB, like -3-4 dB.

[LBHajdu]

That’s a very professional looking amp. How does it sound? How do you set up the amp for measurement with RMAA? Is the schematic of the amp posted somewhere?

[alexw88]

LBHajdu, you can check my web page for the measurement setup and schematic, I only finished one channel so I have not done a proper listening test yet...

Hope to finish the other channel soon.

[jackinnj]

consider mounting the driver board on the left SIDE of the cabinet, away from the large filter cans. You can rig an L-Bracket to do this.

You have what appears to be a common mode choke on the chassis floor (or is this a choke in the capacitor ground connection to limit the turn-on current surge?). If it's a common mode choke, it could be mounted on the rear of the chasis where the mains come in.

No harm in using microphone cable to route the signals (if you don't have microphone cable, you can use CAT-5 cable with one of the conductors grounded.) I would also use CAT-5 cable for the power of the driver board -- it's pretty flexible and can be tacked to the bottom of the chasis.

When you perform tests with a distortion analyzer put the chasis cover on Dress your leads so that power is at right angles to signal.

[alexw88]

Originally posted by jackinnj
You have what appears to be a common mode choke on the chassis floor (or is this a choke in the capacitor ground connection to limit the turn-on current surge?). If it's a common mode choke, it could be mounted on the rear of the chasis where the mains come in.

I connected the PCB ground to the chassis ground / AC main ground thru a choke and a 10ohm resistor in series, the 10ohm can minimize the current flow between the power amp and other equipment, and thus reduce hum. The choke is intended for filtering out the HF noise from the AC ground. I have been searching for a perfect gounding scheme but it seems everyone's grounding method is different.

I am sure the 10ohm here helped a lot to reduce the 50hz hum, but not too sure about the effect of the choke.

Originally posted by jackinnj
No harm in using microphone cable to route the signals (if you don't have microphone cable, you can use CAT-5 cable with one of the conductors grounded.) I would also use CAT-5 cable for the power of the driver board -- it's pretty flexible and can be tacked to the bottom of the chasis.

I am currently using shielded twisted pair for signal, which I think is similar to a microphone cable, right?

[tobias_svensk]

A little bit OT

Where in Taiwan did you get you PCB's for your PA100? and do they do Oz. 2? Your PA100 PCB's look just the PCB's I recieved from Peter Daniel and I liked them.

/ Tobias

[alexw88]

tobias_svensk, I got my PA100 PCB from www.manypcb.com and they only have 0.25 (or 0.5??) oz.

However the PA150 PCB is from www.kgs.com.hk they have 2 oz copper and the quality is better.

Both PCB makers are in Hong Kong, I don't know if they will ship overseas or not.

[motherone]

Very nice work!

[tobias_svensk]

Thanks for the info alex

very nice work indeed.

[alexw88]

Finally I finished the other mono block and listened to them for some time.

The sound characteristic of this BPA300 is similar to my other LM3886 and LM3875 gainclone. These mono blocks has deeper sound stage, better stereo imaging, much tighter and better controlled bass.