For BPA300 there is expensive to us from brazil, but i seaching for BPA200 PCB, without smds 😀
Anyway, i will visit the topic more times!
Hugs
Murilo
Anyway, i will visit the topic more times!
Hugs
Murilo
Finally I tried the LL1545a in my BPA300 :
http://www.shine7.com/audio/bpa300v2.htm
I am now building an active balanced pre-amp to pair with it :
http://www.shine7.com/audio/bpre.htm
Currently I am now using a full balanced connection from the CD player to Preamp to BPA300. The current setting sounds more musical to me. Also by removing the input caps the amp sounds more transparent than before.
http://www.shine7.com/audio/bpa300v2.htm
I am now building an active balanced pre-amp to pair with it :
http://www.shine7.com/audio/bpre.htm
Currently I am now using a full balanced connection from the CD player to Preamp to BPA300. The current setting sounds more musical to me. Also by removing the input caps the amp sounds more transparent than before.
Alexw88
I too would like to buy from that website.
Alex how about posting a sketch or layout schematic of your transformer setup.
How would you implement a balanced input to a preamp like the Aleph 1.7 Thanks Tad
I too would like to buy from that website.
Alex how about posting a sketch or layout schematic of your transformer setup.
How would you implement a balanced input to a preamp like the Aleph 1.7 Thanks Tad
They do have some good DIY components, but you need to know Chinese to buy from them.
Transformer wiring is very simple :
Transformer wiring is very simple :
Hi,alexw88 said:Transformer wiring is very simple :
where does pin 1 go, chassis , or signal ground, or power ground, or somewhere else?
Where does the transformer screen go?
Are there any situations where the normal connection rules for those two grounds should not be followed?
Transformer can + core are connected to signal ground. (as in http://www.lundahl.se/pdfs/datash/1545a.pdf)
Pin 1 is now left open, I have my XLR cable shield connected to my pre-amp's ground.
> Are there any situations where the normal connection rules for those two grounds should not be followed?
Yes, when you are lazy or when your are trying things out. 😀
BTW, I found there are so many connection suggestions for XLR cables, what is normal?
1. http://www.vandenhul.com/artpap/wiring1.htm
2. http://www.jensen-transformers.com/as/as089.pdf
3. http://www.epanorama.net/documents/groundloop/groundlift.html
4. http://www.rane.com/note110.html
Rane suggest connect the shield (pin 1) directly to earth. But I prefer Jensen's suggestion of connecting pin 1 to ground via a resistor + capacitor.
Pin 1 is now left open, I have my XLR cable shield connected to my pre-amp's ground.
> Are there any situations where the normal connection rules for those two grounds should not be followed?
Yes, when you are lazy or when your are trying things out. 😀
BTW, I found there are so many connection suggestions for XLR cables, what is normal?
1. http://www.vandenhul.com/artpap/wiring1.htm
2. http://www.jensen-transformers.com/as/as089.pdf
3. http://www.epanorama.net/documents/groundloop/groundlift.html
4. http://www.rane.com/note110.html
Rane suggest connect the shield (pin 1) directly to earth. But I prefer Jensen's suggestion of connecting pin 1 to ground via a resistor + capacitor.
Hi Alexw88,
about my last BPA300 problem....
I will install DC Protector and soft start circuit in my BPA300, I think is a good option for long term used.
Regards
Jopie
about my last BPA300 problem....
I will install DC Protector and soft start circuit in my BPA300, I think is a good option for long term used.
Regards
Jopie
Hi Alexw88,
For my first BPA300, I bought a speaker protector+soft start (in one pcb) from muzza, this is his thread :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=108671
btw, I've been finished another 2xPA150, without any trouble.
PS, i will post pict later...
Regards
Jopie
For my first BPA300, I bought a speaker protector+soft start (in one pcb) from muzza, this is his thread :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=108671
btw, I've been finished another 2xPA150, without any trouble.
PS, i will post pict later...
Regards
Jopie
Hi Alexw88,
This is not 100% Finished, Chassis not yet anodized and i will modify PSU using Carlosfm design and change the trafo with 300VA 2x25
I will use this PA150 for my front end Home theater.
I build this with standart part and only cost me around $200... so far i'm very happy with it.
After this i will build 5 channel PA150... soft start+speaker protector.
Alex, Why you don't want to make another PA150 beautiful pcbs , I sure some people in this forum have interest to build BPA300,
If you don't like to manage logistic, i will help you to do that or even they want soldered smd part... i can do that too...
Best Regards
Jopie
This is not 100% Finished, Chassis not yet anodized and i will modify PSU using Carlosfm design and change the trafo with 300VA 2x25
I will use this PA150 for my front end Home theater.
I build this with standart part and only cost me around $200... so far i'm very happy with it.
After this i will build 5 channel PA150... soft start+speaker protector.
Alex, Why you don't want to make another PA150 beautiful pcbs , I sure some people in this forum have interest to build BPA300,
If you don't like to manage logistic, i will help you to do that or even they want soldered smd part... i can do that too...
Best Regards
Jopie
Attachments
Jopie, yours is a nice looking amp!
I am not going to make more BPA300 PCBs because it is quite time consuming to do packing, shipment, tracking, and after sales support....
I am not going to make more BPA300 PCBs because it is quite time consuming to do packing, shipment, tracking, and after sales support....
Hi Tad,
Thanks,
I will start building leach amps in january 2008, still waiting some parts from farnell.
Jopie
Thanks,
I will start building leach amps in january 2008, still waiting some parts from farnell.
Jopie
hello
sorry for the noob question but i want to know why there is a 0.2ohm resistor on each of the outputs from the lm3886's
what would happen if you where to remove them??
thanks, pete
sorry for the noob question but i want to know why there is a 0.2ohm resistor on each of the outputs from the lm3886's
what would happen if you where to remove them??
thanks, pete
You can't remove them. See the app note AN-1192 for details, here is the quote :
1% tolerance high wattage ballast resistors are required
when paralleling outputs to keep differently biased outputs
from fighting each other. The wattage rating is dependent
upon the amount of current expected to flow
from each output and the resistance of the ballast resistor;
P = I2R. A good resistance value is 0.1Ω. Amplifier
efficiency is lost if the resistor value is too large like 1Ω
since 10A times 1Ω is 10V of output voltage drop.
1% tolerance high wattage ballast resistors are required
when paralleling outputs to keep differently biased outputs
from fighting each other. The wattage rating is dependent
upon the amount of current expected to flow
from each output and the resistance of the ballast resistor;
P = I2R. A good resistance value is 0.1Ω. Amplifier
efficiency is lost if the resistor value is too large like 1Ω
since 10A times 1Ω is 10V of output voltage drop.