BPA300 Eagle File .BRD - No Catches

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Mayday

Mayday

Member
Joined 2004
DJ Exprice said:
Here's what goes where:

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.



I hope that helps! More to come!



PS: You may want to get the new files from the download. Your board is 100% up-to-date but you may want to take a look at the Eagle files and the specified values for the components. That should help a LOT! :D

PPS: You should definitely place big caps over the primary amplifier +positive+ and =ground= and -negative- so that it's nice and smooth and no issues with thick bass or hum/buzz/60 or 50 cycle.

I have an idea for discharging the caps when the mains power is removed as well. We'll cross that bridge when we get to it though ;). Just a note: it uses relays! :D Fun. (maybe solid state? :eek: Cool ;) :D)

I have HIGH hopes for this project!





-Vince
Click to expand...

So do I Vince, have high hopes that is.


;)

Might be a stupid question, but where are the speaker outs?
 
DJ Exprice

DJ Exprice

Member
Joined 2006
hackybox.com
Oh Sh*t

OH SH*T SH*T SH*T!!!!:bigeyes:


Okay look…the speakers' outputs' kinda got lost :hot:

I have no Idea how that could 've happened! :bawling:

Im freaking out right now and you're going to need a drill to punch an extra hole in the board!


:bawling:
:bawling:
:bawling:


LOOK HERE:

An externally hosted image should be here but it was not working when we last tested it.


Please have mercy! :( I had no Idea that this would…damn. I really need to fix this ASAP!:dodgy:

ONWARD TO EAGLE! :crazy:
 
P

ppcblaster

Member
Joined 2006
Where to get DRV134's Hope this helps

Where can we get a quantity of DRV134 for www.diyaudio.com ?


Thank you for your interest in Texas Instruments. The current distributors for TI are Arrow Electronics, Avnet Electronics or small quantities can be ordered through www.digikey.com.


Regards,

Melissa Ungar
Distribution Coordinator
Schillinger Associates, Inc.
2297 E. Boulevard
Kokomo, IN 46902
765-457-7241
melissa.ungar@sai-rep.com
 
F

Fenris

Member
Joined 2004
Mayday said:
BTW, where am I supposed to measure around the trimpots? And what values will I be looking for?
Click to expand...

I believe you are supposed to measure each output to ground, one at a time (before connecting them together), for DC offset and use the trimpot to zero it out. That way there is no standing DC current being passed between the amps.
 
F

Fenris

Member
Joined 2004
Mayday said:
Thanks!
I'm assuming that you are talking about output pin from chip to gnd?
Click to expand...

Yes, but only from one chipamp at a time, not with all the outputs connected or else they'll interfere with each other.

Also, regarding your other question, the resistor values are supposed to be matched as closely as possible so that the gain of the amps is the same to prevent current from flowing out of one amp and into another. For example, if you have 1 volt in and a gain of 20, then you should have 20v out of each amp (let's assume your power supply and load will allow this). If the amps have for example a 1K and a 20K resistor defining the gain and there's a 1% tolerance, then you have resistance ranges of 990 to 1010 ohms and 19800 to 20200 ohms. Worst case scenario: one set of resisors with 990 and 20200 and another amp in parallel with 1010 and 19800. You would have a gain of 20.4 for the first amp and 19.6 for the second. At 1v in, one amp will put out 20.4 volts and the other 19.6 volts. Now you've got a 0.8v differential. If there were nothing to limit the current, it would flow backward through the lower gain amp and eventually destroy it. However, that's why we have the small output resistors - they limit the current these small voltage differentials can transfer between amps. With 0.2 ohm resistors on each output (the outputs see 0.4 ohms total between them), you have 2 amps of current (I=V/R). This is less than what is being output from the smaller gain amp (it's probably pushing 5 amps into 4 ohms), so current won't flow back into the amp, but you will reduce output due to the opposing current flow and increase heat output. Of course, this is also a worst case scenario, in reality the resistors will probably be much better matched and you won't run at 20v output. This also why 5% resistors shouldn't be used unless you hand match them.
 
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