OMG, this is fantastic.
It may some time to fully absorb and build the test leads - but ill get into this project and report back.
Thank you !
It may some time to fully absorb and build the test leads - but ill get into this project and report back.
Thank you !
Just so im clear on this critical part of the instructions:
when you say "now - all inputs grounded ; most practical way is to put shorties on XLR's (pins 1 and 3) and on RCA's , so practically pin 2 of XLR is also shorted to gnd ;"
Do you mean short XLR inputs pins 1 &3 and, at the same time, short the RCA input's positive and negative ?
That seems a bit dangerous....
when you say "now - all inputs grounded ; most practical way is to put shorties on XLR's (pins 1 and 3) and on RCA's , so practically pin 2 of XLR is also shorted to gnd ;"
Do you mean short XLR inputs pins 1 &3 and, at the same time, short the RCA input's positive and negative ?
That seems a bit dangerous....
goal is to have all 3 xlr pins tied , so both inputs (pos. and neg.) grounded
RCA is , whatever, connected to pins 1 and 2 of XLR
it's the same as that you have attenuator there , turned to min. volume
RCA is , whatever, connected to pins 1 and 2 of XLR
it's the same as that you have attenuator there , turned to min. volume
Zen,
i took me some time to get my hands on 2 DVMs and set up this adjustment but i finally got around to it. Sorry for any delay.
i have now completed and have gotten the offsets down to within spec ( 50mv for the absolute and about 300 Mv against ground).
One thing i should mention for other who might try this - i found that the opposite trim pots seemed to effect the voltages leading me to believe that perhaps P1 and P2 may be mislabeled on the above attached image - so that for eg P2 is beside the "USG4" label on the circuit board and P1 is beside the 'Pass' label on the circuit board...
Thank you again Zen for your expert advise and very detailed instructions.
Britshc
i took me some time to get my hands on 2 DVMs and set up this adjustment but i finally got around to it. Sorry for any delay.
i have now completed and have gotten the offsets down to within spec ( 50mv for the absolute and about 300 Mv against ground).
One thing i should mention for other who might try this - i found that the opposite trim pots seemed to effect the voltages leading me to believe that perhaps P1 and P2 may be mislabeled on the above attached image - so that for eg P2 is beside the "USG4" label on the circuit board and P1 is beside the 'Pass' label on the circuit board...
Thank you again Zen for your expert advise and very detailed instructions.
Britshc
Attachments
well , it's always possible that I turned it around while looking between schematic and pcb/pics
however , looking at DVMs , it's pretty much self explanatory what's influencing what , as you figured it out
further impressions/situation in your sound system now , any changes made ?
however , looking at DVMs , it's pretty much self explanatory what's influencing what , as you figured it out
further impressions/situation in your sound system now , any changes made ?
From the close up of the circuit board, its very difficult to determine its orientation. Having two DVMs was a brilliant, because you can monitor both adjustments at the same time. This reduces the possibility of making too large a change.
Definitely an improvement in presentation. The other issues i had turned out to be software related. Changing to a different source (LP) reveled the issue. New software installed, computer audio is back to normal.
Thxs again. Ill check the adjustments again in a month to make sure they are fully stable.
Britshc
- Status
- Not open for further replies.