One of my N72s - 5-6 db lower out level

[tree]

hi -
i've just completed 4 N72 builds - all GREAT, but one of them has about a 5-6db lower output and seems to be missing some low end info. i haven't found anything yet directly related to this issue on the message board.
i've re-examined all solder joints and they all look good - quite clean, def. no visible bridges ... rechecked values of components around
the inputs and outputs... all looks right so far.
Can anyone suggest any areas of the board i should pay particularly closer attention to, areas to maybe reflow ?

apologies, i've had some experience building, but still pretty green to the scene !

[tree]

a bit frustrating...
reflowed bunch of things around input and output then everything around Q4,Q5 and Q6 (and related resistors). Then re-biased R39 as described in the assembly instructions.
checked it with audio and it seemed to be behaving (yay!), BUT ... then after i put it all back together in the case, checked it again and there it was again 6 db lower on module #4!!!

any suggestions out there sure would be much appreciated.

[tpryan]

Are you absolutely sure it's not a problem with your cabling, patchbay, mixer, converter, etc.? What is your test procedure? Is the difference exactly 6dB?

[tree]

sent a console test tone (neotek elite) out one line and that one line plugged into the input of a "good" module with the single return line from that module output plugged into to a single channel of the desk, set to read 0db.
then i set the "bad" module gain and trim as identically as possible to the "good" one (gain switch at 16 & trim pot around 1'oclock) - and A-B'd "good " and "bad" by simply swapping the two cables (input & output) back and forth manually between the two N72s.
the neotek rtn ch. meter showed the "bad" module as consistently having about 6db lower output level. i say, "about" because the neotek leds are a slight bit "give or take" when they're at the low end of their scale and of course, the N72s have no indents on their trim pots ...

anyway...

thought the 6db aspect might be pointing toward some kind of a balancing issue so i pulled the module, reflowed all the output transformer joints, plugged it back in, fired it up, and - presto-change-o!! - 0db on the rtn!

knock on wood, looks like we're back in business.

really looking forward to using these - all eight!
they're in good company here alongside vintage 1079s and quad eights.