there are I believe two main schools of thought on htis one:
First: Place the same capacitance as you would for each single channel where you normaly would as though each chip was acting independantly of the others.
Second: Have one large bank of caps (as with a conventional PSU) and then use smaller decoupling caps close to each individual chip as before (but using much smaller caps than you normaly would).
I have noe experience of either of these layout (yet), but if this is a first attempt at this, I would use the one which is easier to implement for you at first, and if you are not happy you can easily change it later on (unless you use a PCB).
Andrew.
First: Place the same capacitance as you would for each single channel where you normaly would as though each chip was acting independantly of the others.
Second: Have one large bank of caps (as with a conventional PSU) and then use smaller decoupling caps close to each individual chip as before (but using much smaller caps than you normaly would).
I have noe experience of either of these layout (yet), but if this is a first attempt at this, I would use the one which is easier to implement for you at first, and if you are not happy you can easily change it later on (unless you use a PCB).
Andrew.
The resistor tolerences for the feedback resistors should be as good as you can get them, idealy 0.1% or better.
Also, I would consider slightly larger output resistors (national recomend 0.22 as a minimum if I recall correctly, or else they may not work correctly) but I'm not too sure where you might find them (I know Dale produce high power and close tolerance wire wound type, and I think Vishay produce precision resisotrs in a T220 package which would run at 5W with a small heatsink).
As far as the DRV134 I'm not too sure, I would just go to naationals website and look it up in the data sheet.
Also, I would consider slightly larger output resistors (national recomend 0.22 as a minimum if I recall correctly, or else they may not work correctly) but I'm not too sure where you might find them (I know Dale produce high power and close tolerance wire wound type, and I think Vishay produce precision resisotrs in a T220 package which would run at 5W with a small heatsink).
As far as the DRV134 I'm not too sure, I would just go to naationals website and look it up in the data sheet.
Hi, the tollerence of the output resistors is not too critical when it comes down to it, as they are only there to make sure the chip amps share the current equaly between them, and if you can get this down so that there is no more than 5% difference between the chips that should be good enough (although, if you do want better, just buy more resistors than you need and match them up by yourself with a good multi meter).
As far as the Transformer goes, you will only need one for each speaker you use, so yes, one for each set of chip amps.
And if you do use a zobel, I think it wouild be ok to just yse one, placed directly at the output after all of current matching resistors.
As far as the Transformer goes, you will only need one for each speaker you use, so yes, one for each set of chip amps.
And if you do use a zobel, I think it wouild be ok to just yse one, placed directly at the output after all of current matching resistors.
bigparsnip,
Thanks for the info. I already have a 2 channel gc that works. My plan is to parallel my existing 2 channel and build another 2 channel and parallel it with the 0.1 ohms of course. Then I will bridge them with a drv134 (on it's way
). The reason I ask about the zobel is because my pcb has provisions for them and my existing 2 channels have zobel at the output. Thanks again!
If you have other pointers please post them.
JojoD
Thanks for the info. I already have a 2 channel gc that works. My plan is to parallel my existing 2 channel and build another 2 channel and parallel it with the 0.1 ohms of course. Then I will bridge them with a drv134 (on it's way
). The reason I ask about the zobel is because my pcb has provisions for them and my existing 2 channels have zobel at the output. Thanks again!If you have other pointers please post them.
JojoD
I have successfully bridge/parallel the OPA549. Now a I want to try the OPA541.
There is already a 0.1ohms resistor from the output going to the speaker which is also used for current sense pin.
Do i still need to series another 0.1ohms to parallel 2 OPA541s? If not, for a 4 cell amp (bridge/parallel), the amps in parallel will have their current sense pin 8 tied together, is this ok?
Please help.
JojoD
There is already a 0.1ohms resistor from the output going to the speaker which is also used for current sense pin.
Do i still need to series another 0.1ohms to parallel 2 OPA541s? If not, for a 4 cell amp (bridge/parallel), the amps in parallel will have their current sense pin 8 tied together, is this ok?
Please help.
JojoD
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