Another BPA 300 Build thread...newb perspective

[HaLo6]

So I am a newb at this.. so I thought I would make a thread detailing all my work at building a BPA 300 amp from Rhysh's BPA 300 Group Buy thread... (still awaiting the arrival of the boards)

Right now I am sourcing a case, learning about PSU design... etc...

I think I am going to use a Par Metal 20 Series case , but modified, I am basically going to ditch the tops and sides. The sides will be Conrad MF35-151.5 and the top I am going to try to get an acryllic top made or a metal grated top, i have seen both used here on the forums and they both look cool. (well see how that turns out)

For the Trafo, I am thinking about this Plitron toroid, its 1000VA 4x30VAC at 8A per output, part number 7393-B2-00. I am also thinking about using AMB Labs Sigma22 for regulation, one for each pair of boards. AMB Labs has a cool amp build called the B24 that I am trying to blend in ideas....

Project in its infancy... i'll post more as I go along... if anyone wants to share in this build please chime in!

[HaLo6]

So I thought about another idea... what about splitting the amp into the PSU section in one case and the LM3886 boards in another (right above)

Basically have two umbilicals carrying +/-30VDC to each section of the BPA...

I'll draw out my idea...


The only thing that sucks is thats alot of wasted space in the second case... but it may be a tight fit to get all the other stuff in one case...

(Trafo in the pic should be 4x30VAC secondaries, 2 to each Sigma22)

[juluska]

Originally posted by HaLo6
So I thought about another idea... what about splitting the amp into the PSU section in one case and the LM3886 boards in another (right above)

Basically have two umbilicals carrying +/-30VDC to each section of the BPA...

I'll draw out my idea...


The only thing that sucks is thats alot of wasted space in the second case... but it may be a tight fit to get all the other stuff in one case...

(Trafo in the pic should be 4x30VAC secondaries, 2 to each Sigma22)

my bpa300 integrated amplifier layout:
http://ignatiusprojects.blogspot.com/

[CJ900RR]

30V AC will give you about 42V DC. That is a bit to high I think. 25V AC would be better (read safer).

Regarding case configuration, I would (and have) gone either dual mono in one case, or just 2 mono amplifiers. Use 1 trafo/2 boards. 2 pcs of 600VA trafo would suit your needs then. Dual mono also helps to minimize the risk for ground loops.

Other wise I wish you good look. The BPA300 is a great sounding implementation of the LM3886 with a lot of power.

[pacificblue]

Originally posted by CJ900RR
30V AC will give you about 42V DC. That is a bit to high I think.

Depends on the load and the heatsinking. If BPA-200 is stable into 8 Ohm with 30 V AC, BPA-300 should be good for 6 Ohm with that voltage. With 4 Ohm speakers 25 V AC should be the limit.

30 V AC will give 42 V DC nominal rails voltage, i. e. at low power output. Fully loaded it will drop to something like 37 V DC.

[rhysh]

Nick, why not have a go at building monoblocks? As you are looking at two seperate cases anyway it wouldnt really make too much of a diffrence in price. I have found the BPA300 to perform better with two seperate transformers anyhow.

Not to mention, it really looks the part

[Ted205]

I'm working on the same project.
I'm going down the dual mono - two cases route (PSU and amp).
2x 500VA 25v-25v 40mF.
Also worth thinking about a softstart

How are you planning to bridge the signal ? I was planning to use LM4562 setup as balanced line drivers as this IC is sounding really good in my current preamp

[CJ900RR]

Originally posted by Ted205
How are you planning to bridge the signal ? I was planning to use LM4562 setup as balanced line drivers as this IC is sounding really good in my current preamp

That I can confirm is a setup well worth time and money!

[peranders]

2 x 30 VAC toroid transformer means 30 VAC at full load meaning more than 42 VDC and certainly more at idle state. 2 x 24-25 VAC would I recommend and at the most 2 x 28 VAC. Remember that we talk about deciBells in output power (you won't notice the difference) but you will run the amp much more safe and it will also run cooler.

[HaLo6]

Great ideas... I was thinking about dual mono but was trying to avoid the cost of two trafos, and then I saw the Plitron with 4 secondaries... and the heatsink look on the side.... If I go dual mono one heatsink goes in each case.... then I wouldn't use the sides... well maybe Ill go with a modushop.biz case then the Pesante 3U... choices choices...