With no signal it remains cool, Add a small signal and it quickly gets hot
.
I do have a star ground in the amp and in the psu.
RCAs are isolated.
.25 ohm on each output
no zobel
I know that some people have problems with Oscillation in the absence of input but my problem is the opposite.
also, could someone tell me if my implementation of the .25 ohm resisters on the outputs its the correct way to paralell two amps.
.I do have a star ground in the amp and in the psu.
RCAs are isolated.
.25 ohm on each output
no zobel
I know that some people have problems with Oscillation in the absence of input but my problem is the opposite.
also, could someone tell me if my implementation of the .25 ohm resisters on the outputs its the correct way to paralell two amps.
lay out
Its pretty simple,
I just put two .5 ohm resisters back to back and soldered them together. Placing two legs in the OUT hole of the board and connecting a wire to the other two leggs Resulting in a .25 ohm in series with each boards output. I then connected the two wires(post resister) to each other and on to the positive output post on the chassis.
The amp acts as though it's output is shorted, but I tested that.
I am trying to add a pic and I don't know if its working but you can see the resisters mounted in the board, but there is nothing attached to them in one pic. In another pic, the blue and white wires are my output leads.
Its pretty simple,
I just put two .5 ohm resisters back to back and soldered them together. Placing two legs in the OUT hole of the board and connecting a wire to the other two leggs Resulting in a .25 ohm in series with each boards output. I then connected the two wires(post resister) to each other and on to the positive output post on the chassis.
The amp acts as though it's output is shorted, but I tested that.
I am trying to add a pic and I don't know if its working but you can see the resisters mounted in the board, but there is nothing attached to them in one pic. In another pic, the blue and white wires are my output leads.
Attachments
testing
I have not test the boards individualy, but both channels are doing the same thing. Also, the kits are from two different batches of kits, therefore it leads me to believe there is fault with my implementation.
This is my second project using the same kit. The first one was a complete success.
I have not test the boards individualy, but both channels are doing the same thing. Also, the kits are from two different batches of kits, therefore it leads me to believe there is fault with my implementation.
This is my second project using the same kit. The first one was a complete success.
Hi-
You mentioned one set works fine and when you add the second set it goes to crap.
Are you using two boards X two channels, or 4 boards per channel?
From the picture I "assumed" the four boards were for two channels.
So if one set works correct (right or left channel, channel 1 or 2, or whatever) then the issue is a board build or parts issue on one channel.
If it is 4 boards paralleled, then it "may" be an interaction issue (drive signal seeing low input impedance of 4 boards...)
If they are parallel boards, then it should be very easy to clip on test leads to each boards output to hear individually.
Good luck,
Troy
You mentioned one set works fine and when you add the second set it goes to crap.
Are you using two boards X two channels, or 4 boards per channel?
From the picture I "assumed" the four boards were for two channels.
So if one set works correct (right or left channel, channel 1 or 2, or whatever) then the issue is a board build or parts issue on one channel.
If it is 4 boards paralleled, then it "may" be an interaction issue (drive signal seeing low input impedance of 4 boards...)
If they are parallel boards, then it should be very easy to clip on test leads to each boards output to hear individually.
Good luck,
Troy
Do you have any resistors in series at the output? It seems that you just have connected them in parallel without this crucial resistor, somewhere between 0.22-033 ohms I'll belive is the value.
EDIT: It seems that you have those resistors but how about your offeset voltage? Maybe it's too high => currents flow between the IC's.
EDIT: It seems that you have those resistors but how about your offeset voltage? Maybe it's too high => currents flow between the IC's.
DC off set and other clairification
I tested the DC offset and it was around .045 volts when the 2 boards per channel were paralelled and no input.
I think that this is in line with correct operation.
The configuration goal is to use 2 boards per channel for a stereo set using 4 boards.
When I disconnect the out leads on the second set (resulting in normal one board pre channel configuration) everything works fine. But, if i make the connection to paralell the second board the output drops and distorts.
I tested the DC offset and it was around .045 volts when the 2 boards per channel were paralelled and no input.
I think that this is in line with correct operation.
The configuration goal is to use 2 boards per channel for a stereo set using 4 boards.
When I disconnect the out leads on the second set (resulting in normal one board pre channel configuration) everything works fine. But, if i make the connection to paralell the second board the output drops and distorts.
problem solved
I had reversed the positions of r1 and r2. On the scope it did not show any obvious difference untill I realized the HUGE difference in gain between the two sets of boards.
Now the amp is pumping watts into a 3 ohm load and loving life in the living room.
Thankyou all for your input and help.
I now need to find a input buffer kit or detailed instruction on one. Does anybody know of such?
I had reversed the positions of r1 and r2. On the scope it did not show any obvious difference untill I realized the HUGE difference in gain between the two sets of boards.
Now the amp is pumping watts into a 3 ohm load and loving life in the living room.
Thankyou all for your input and help.
I now need to find a input buffer kit or detailed instruction on one. Does anybody know of such?
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