GSSL Output help Left Right are un-even

Dear All:
Testing my second GSSL , but found that Left side and right side has about 3dB difference in Volume means the leftside is a bit louder and little over dirving wihle operating , I checked everything and all trace I dont see anything wrong , am I missing something? Please help.. also tried to calibrate still nothing happen
adky

make sure all solder joints are complete and not 'shaky'

make sure there are no shorts on any output wiring. also might want to give the output chips (the 5532's) a bit of a wiggle to ensure that the problem isnt a bad connection from chip to socket, or from socket to pcb.

super quintuple check, it MIGHT be a chip, and you may want to replace them.. i finally just ordered a decent amount of 5532's and 5534's just because its nice to have extras.

but almost every time its a short, a bad solder joint, a miswire or an incorrect component (usually resistors)

i would check in that order:

bad joints (you can always just go through and give them a touch up),

shorts.... check very close pads for shorts with the DMM looking for 0 resistance, and have a printout of the circuit layout handy to check if they should or shouldnt be shorted.. sometimes its hard to know, because for some they are supposed to be making contact.

check wiring... *everybody* does silly stuff.... just double check

try the Chip Wiggle ;]

and if there are still probs, print out a resistor color code chart (they're all over the web) and check all the resistors ;] sucks, but thats what it comes down to sometimes.... it'll def teach you to measure every R before you put it in a board.

and once, testing a g1176, i realized that i had a bad cable on the output, and i had torn ALL my hair out trying to get it going..... it seriously *is* usually simple, just tedious....

it'll come through ;]

billy

Scope it and see WHERE the difference happens.

Keith

well yeah

it's definitely easier and the way to do things.

i didnt always have a scope however....

but then again, that free pc oscilloscope is pretty decent for stuff like this.

Best to use the official help thread for questions - easier to find at a later time..

Jakob E.

I remember we once had a "search this topic" button, but I cannot find it anymore. It's really hard to go through a topic of nearly 100 pages. :sad:

Check the "posts" button instead of the "topics" on the lower left.

It saves trawling through 100 pages.

But it's very simple to follow the GSSL signal path: if you don't have a scope, use an AC voltmeter. Send the same signal to both inputs at the same level. Read pin 6 of one 5534, then pin 6 of the other 5534. -The same?-Move on.

Read pin 1 of one 5532, then pin 2 of the other 5532. =The same? move on. Read pin 7 of one 5532, then pin 7 of the other.

Somewhere there should be a difference. Find where and you found the problem. the 5534 is the input buffer. the first half of the 5532 is the VCA I-V (current-to-voltage) follower. The second half of the 5532 is the balance driver.

If the VCA follower is where the level goes wrong, check for wrong components (resistor values) in the vicinity of the VCA, and also the inverting node feedback resistor between pins 1 and 2.

Its not usually hte active components, but if you socketed them (like a good boy should!) you can swap the 5532, the VCA and the 5532 between channels, and eliminate those.

It's almost invariably a wrongly-placed resistor value, or a solder bridge.

Keith

Thanks SSLtech i mearsured out its read the same then i tried everything ,check every resistor value , even replace the output resistor to 180r and still nothing happen , same behaiver, but if i do a hard compression it sounded normal...also changed the unity gain resistor from 15k to 27k still the same behaiver... swaped all the chips with new one ... same...
should i forget it and do a new one? :grin:

I think 3dB diference is problem of the balanced receiver or driver. check if you have true balanced output , if one of the + or - output is not working you have a 3db lower signal.

..naa, that'd be 6dB..

[quote author="gyraf"]..naa, that'd be 6dB..[/quote]
What he said.

Keith

[quote author="gyraf"]..naa, that'd be 6dB..[/quote]
What he said.

Send it to me and I'll fix it for the donation of a single set of blue PCB's!

-No seriously! -Continuing the "Bloo" theme of my LA2a and 1176's, I think it'd be seriously cool to do a "true blue" GSSL...

-If you measure all the same AC voltages at the pins that I mentioned, then check the resistors and caps between pin 1 & 7 of the 5532 and the outputs. Measure voltages there WHILE YOU HAVE THE LOAD CONNECTED... They can't really be the same and have different levels...

Keith

Sure SSLTECH! your responses is already very helpful , PM me your address I will send you a set of "TURE BLUE" NP ... FYI: I also got "TURE RED" 9K PCB :grin: