Bridgeclone

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#121
Aunkst said:
I think this is an excellent question. I don't have the printed boards, but just how easy is it to bridge two amps together?

I'm learning alot, but some of the finer details excape me at this point.
Click to expand...

I would hold out on this project for now, unless you have access to lab equipment. I am going to go into lab within the next week, and prototype a bridgeclone with my boards, and the DRV134 chips (see above posts for some details). My initial assumption is that with matched components on the boards and a 0.22ohm output resistor, it should work fine with the DRV134 chip, but I will verify this in lab with a scope, and do some testing.

--
Brian
 
#122
That's exactly what I was thinking Brian. As long as the components are well matched, it should work fine. I was planning on putting one together in this configuration sometime this week. I have a scope at work, and can check for oscillations. I'll have to let you know how it goes.

Cheers,
Zach
 
#123
ok, i guess that pretty much answers my question. i wasnt sure if it was that easy (well, sorta), but i guess it seems its pretty possible if everything is pretty well matched. looks like i gotta get rid of those occasional radio shack resistors (gasp....i had messed up with one on each board...)
 
#124
BrianGT said:


I would hold out on this project for now, unless you have access to lab equipment. I--
Brian
Click to expand...


Ahh, But I do have access to a good scope, (1st year EE student). lay some procedure on me,
youre' saying:
1. build both sides with matched components.
2. test each side independantly.
3. use resistors to set output current EQUAL.
4. use a DRV134 to split the phase and drive each side of the bridge.

sounds simple.

when I am scoping for oscillation, what would I look for?
 
#125
Aunkst said:
Ahh, But I do have access to a good scope, (1st year EE student). lay some procedure on me,
youre' saying:
1. build both sides with matched components.
2. test each side independantly.
3. use resistors to set output current EQUAL.
4. use a DRV134 to split the phase and drive each side of the bridge.
Click to expand...


Sounds like you have it covered. I would just input a sinusoid from a functional generator and verify that you have a clean output, checking the gain, and the level of power output obtained under load.

--
Brian
 
#130
if you are going to build this, don't attempt Vectorboard, you definitely need a PCB (the pins themselves are only 20 mils, the spacing is quite compact):
An externally hosted image should be here but it was not working when we last tested it.


this is a "fair" idea of what the PCB should look like:

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


I've had some proto's burned, they just arrived so haven't been tested.
 
#136
What is abundantly clear after testing this amplifier at 100 watts is that you can't kid around with the heatsinking of the chip in the bridged version. Machine screws are not sufficient to get the best contact between the chip and heatsink -- you have to use a fixture which compresses the chip against the sink and thermal grease.
 

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#138
the schematic follows the National Semi design, and the PCB design follow this -- from the hints that they give you on their zipped files and the pictures of the finished board you should be able to do it pretty quickly -- if you want to roll your own remember that the size of the LM4780's pins are 21 mils. I put a power plane on the bottom and ran the power leads at (I think) 200 mils.
 
#139
Ballanced bridge clone

I have some designing problems with mij bridge clone,
I`am using a jensen JT-11p-1 input transformer as a buffer.
which drives (+ and -) a total of 4 non-inverted lm3886`s

can the scematic (pic) be used as it is?

what resistor values do i need for best impendance matching?

R1= 1K?(riken ohm)

What resistor values for R2,R3? (22k , 680R vishay s102)

My powersupply wil be a 2X22v= 500va torroid

R4=0,22ohm dale


Maybe Kuei Yang Wang can help me on the trafo thing......



Menno
 

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