Finishing pimeta - how 'exact' is exact ?

[solid]

While making a pimeta amp, I'm stuck on measuring the voltages now. The LED burns and nothing gets hot, so I started measuring the chips' pins.
The CMOY guide sais as follows:

you should see a positive DC voltage at one cap and a negative voltage at the other cap, and their magnitudes should be nearly identical. For example, if you're using a 9V battery that's been depleted to 8V, you should see almost exactly +4VDC and -4VDC. If you're off by more than a tenth of a volt or so, you did something wrong in hooking the circuit up.

The voltages I got, are not exactly identical, I put them in the schematic at the pin they were measured (I used the Pot Ground as Virtual Ground):



Values in Volt, btw. Also, I get a reading where I guess I shouldn't ? (The circled one)
Very strange, because I haven't soldered anything at the buffer pads yet (not even sockets) because I've got the SO-8 version of the chip and decided not to solder it down until the rest was finished. Any ideas on what this might be ?

[tangent]

Looks like your measurements are "off by a tenth of a volt or so". Perfectly normal. The TLE2426 is not perfect.

Regarding your circled pin, follow the thick blue trace to the left, and you will have solved the puzzle.

[solid]

Thanks, when I think about it.. some more confidence on my part couldn't hurt .


I installed the buffers now, the first 2 (left and right chanel) went allright, however after putting the batteries in the third one (ground chanel) got *really* hot .
Strange thing is that it looks almost exactly the same to me, as the other 2.
Since I rather wouldn't desolder it yet because of the smallness of the part, can anyone help advise on where to start/what would most likely be the problem ?
I'd be grateful for any suggestions.

[Dreamslacker]

Originally posted by solid
Thanks, when I think about it.. some more confidence on my part couldn't hurt .


I installed the buffers now, the first 2 (left and right chanel) went allright, however after putting the batteries in the third one (ground chanel) got *really* hot .
Strange thing is that it looks almost exactly the same to me, as the other 2.
Since I rather wouldn't desolder it yet because of the smallness of the part, can anyone help advise on where to start/what would most likely be the problem ?
I'd be grateful for any suggestions.

If you've jumpered R11G, then the buffer is in Ultra-wide bandwidth mode and would get warm/ hot. You can use thermal epoxy to stick a small heatsink on the buffer if you wish.

[solid]

None of the R11's are jumpered, I used a 3K3 Ohm resistor for each.
The joints of R11g are looking quite nice as well. Should I search better in the signalpath of the resister ?

[solid]

Could it have something to do with the AD8210 (ground amp) not sticking in it's socket very well? I didn't dare to use much force on it, it looked kinda vulnerable.

But now it still sticks out about 4mm, however I thought all the legs made a connection.