Would you be interested in a BPA-200 kit?

[los_ren]

sry, been busy.

will do soon tho =].

(before i do i wanna see if i can run a board bridged , but not paralleled using two PCBs, into an 8ohm load with a 25v psu).

 

[nobody special]

sounds cool... better have some good heatsinking!

 

[peranders]

Some ideas for the PC board are:
Up to 8 3886's per board (per channel).

Don't overdo things.

1 LM3886 gives you ?? Watts
2 LM3886 gives you ?? Watts
4 LM3886 gives you ?? Watts
6 LM3886 gives you ?? Watts
8 LM3886 gives you ?? Watts

For you to fill in. It seems that 4 LM3886 is optimum. Adding 4 extra LM3886 adds very little costs twice!

 

[tlmadsen]

optimum number of LM3886

Dear P-A

I am not sure that 4 x is the "optimum" number of LM3886 to use in a BPA-config. 4 is actually the minimum you need to make a BPA-config.

For a lot of people 2x2(4 pices of LM3886) if fine, but from a more "technical point of view" I think (I have not doen the calcualtions) 2x3 (=6 pices of LM3886) is closer to the point of "deminishing return", if you can call that point "otimum".

To Nobody sepcial.
Remember to take care of the DC-offset if peopel don't use the DC-servos

..........have fun

Thomas

 

[Tweeker]

I woud like to make a sub amp to power an Acendant Avalanche 18 in a very large folded transmission line. I was thinking either 4 LM4780 or 8 LM3886 in bap arrangement would do the job. Cooling would be a concern. This woofer could easily eat 544 watts in such an enclosure. So I would definetly be interested in such a beast.

I have no problems with buying foreign goods, except my goverment is running a massive deficit, and we have a voracious appetite for cheap chinese crud and gasoline, so the trade balance isnt so good either. My dollars dont go quite as far as they used to overseas.

 

[peranders]

Re: optimum number of LM3886

I am not sure that 4 x is the "optimum" number of LM3886 to use in a BPA-config. 4 is actually the minimum you need to make a BPA-config.
/B]

I ment also when you take into account how many extra dB's you will get with these extra two LM3886 but I'll guess this also has to do with the cooling arrangements. More LM's are easier to cool.

 

[nobody special]

Re: Re: optimum number of LM3886

I ment also when you take into account how many extra dB's you will get with these extra two LM3886 but I'll guess this also has to do with the cooling arrangements. More LM's are easier to cool.

Exactly my thoughts for why to use 8. Less current per device for a given wattage into a given impedance, more surface area to heat sink. I know there will be some that will want to push the amp hard into 4 ohms.

 

[nobody special]

Re: optimum number of LM3886

To Nobody sepcial.
Remember to take care of the DC-offset if peopel don't use the DC-servos

..........have fun

Thomas [/B]

Thanks for the pointer, Thomas. I'm still debating whether to even bother with not using the servos. I think the design really does need them, and I don't want to deal with people freaking out about the amp not working when they don't use them.
Developement continues... Building a lot of parts in P-cad currently. I hope to have a prototype amp built very soon.
I also have an interesting plan for the heat sink adapter which will allow direct mounting of the 3886T(non-insulated) devices and more surface area for good heat distribution while still isolating the devices from the heat sink.
How many reading this would prefer a design that would mount the pcb parallel with the heat sink as opposed to perpendicular? My original intent was to provide a board that would mount perpendicular to the heat sink, and offer left and right versions for a stereo amp with side mounted heat sinks. If I find there is more need for it to be parallel-mounted, I will take that into consideration.

 

[tlmadsen]

Steve .

There are ways that it would work fine without the servos, so you might consider it.

Thomas

Go for the parallel mounting of the LM3886 (despite that I, myself did not on Das Modul)