BPA-200 w/ six chips working w/ pics!

[Mattyo5]

Ok, you asked for it. If someone wants to host bigger pics let me know, otherwise, this is all i can post ... i take back what i said before, the amps are crazy loud. Quite nice sounding too. My wife was really impressed. I can get them to distort if i do crank em, but i also had both my main speakers plugged into one amp to see how it did w/ a 4 ohm load...handled it quite nicely even when cranked... got a little warmer, but the heatsinks although not optimally positioned, worked fine.

Later!

-Matthew K. Olson

[Mattyo5]

another

check out my power cables 3x10awg w/ marinco IEC's. sweet

-Matthew K. olson

[Optical]

looking good there!
how is your dc offset? do you think it could be capable of powering some PA speakers (fairly big ones) quite well?

[carlosfm]

Originally posted by Mattyo5
My wife was really impressed.

That's good.

[Mattyo5]

DC offset is about 2mV. Very little offset. Idling heatsink temp is very cool. Sinks get quite warm into 4 ohm load, but they never get hot even when driven hard into an 8 ohm load. If you wanted to drive PA speakers, i'd have a 800-1kva toroidal PER channel 25-0-25 or 30-0-30 would work, although 25-0-25 would be better i think. I'd really like to finalize a pcb for this amp, now i've proven the design works ptp... although it was a lot of work to get these things soldered up. Anyway, good luck w/ it if you do decide to use it

-Matthew K. Olson

[cdoggy81]

Looking good Matt!!! :-)

[Mattyo5]

thanks, top grills are on the way asap

-Matthew K. Olson

[tg3]

Originally posted by Mattyo5

i think the switch is causing the popps... its only a 6A rated switch... i'm using a 3A inrush current limiter though... who knows

Hey, Matthew. Good to see you're hard at work on another power amp.

Oddly enough, the power switch is stressed more when the amp is turned off. Something about collapsing fields on the transformer, which would not be affected by the inrush limiter.

I learned this tidbit from Hugh Dean in this post on the AudioCircle.

Best regards.

[carlmart]

Originally posted by tg3

Oddly enough, the power switch is stressed more when the amp is turned off. Something about collapsing fields on the transformer, which would not be affected by the inrush limiter.

I learned this tidbit from Hugh Dean in this post on the AudioCircle.

Great tip! Hugh also suggests that a bypass (snubber) cap between the switch contacts reduces this problem.

So don't forget to add something like a 10n cap, at least 600v if possible.


Carlos

[Mattyo5]

I have a .22uf cap across AC mains, 250vac... doesn't help any. One amp has it, the other doesn't. Does it need to be closer to the switch? (there is no room for me to get in there)...doh. Higher voltage needed? again doh, just put in an order to digikey... thanks guys

-Matthew K. Olson