replies from Gregory:
Hi Gregory,
Regarding the XLRs, you say it's OK to use non-shielded wire but is shielded preferred? And would all the shielded wire in the box be 2 conductor with the shield around it? 22 guage oK?
Should I twist all non-shielded wire, like to the VU meter?
A: useing twisted wire works great ! use as mush as you need to elegantly string a conection from the xlr to the floor of the case , to the pcb pads.
STAR GROUND TRANS. QUESTION:
I currently have my green yellow wire from the Allied transformer soldered to the board. Is it OK to have the red yellow wire connected to the star ground in this case or should my green yellow wire also go to the star ground?
A: yes the green yellow is the center tap for the low voltage , it goes to the pcb pad 'LV CT tap '
you must have the high voltage center tap (red yellow) grounded to the case (other wise the power supply wont work)
do not place the (red/yellow) lead to the LV CT pcb pad other wise youll smoke the transformer.
GROUND 1,2,3
To the same location? Star ground or near the XLR?
A : ive had good luck with this configuration , but grounding everything to the transformer star ground works too .
and more:
yeah , the shield is mainly for a longer wire run , but for 1-2 inches , i wouldn't bother ,
even in the real la2a , the meter section , that is connected directly to the xlr out pin 1&2 uses twisted wire un shielded .
and its about a 10" inch run .
as far as the lug , one is as good as two separate ,
a solder lug inbetween should work fine for both of them ,
ive tried also to send every thing to the star ground at the transformer lug , this works well too ,
jensen transformer notes pin 1 should be the shortest possible connected next a ground located at the base of the the xlr sockets,.
but they also reccomend a 51 ohm resistor in series with a 10n cap ( .1 i think , will have to verify that )
meaning a 51 ohm resistor connected directly to a .1 cap connected to ground , (havent tried this , could be better )
still more:
just to verify ,
both the direct to ground from the switch and also the 'lifted' ground can be the same place ,
it is recommended that these grounds be located directly next to the xlr sock (if not to a bolt that actually connects the socket to the case)
how ever , i find it is not too finicky about this it can be just 1 solder lug located inbetween both the in and out socket.
this is also a good point to solder all the 3 ground wires from the pcb (audio, reduction, input) to .
some people recommend keeping these grounds separate from the power grounds.
but in all honesty , there actualy is not a science to this ,
it is more of a speculation . (thats a very factual statement when it comes to grounding issues)
ive tried just about every situation of grounding ,
even wired a case with over 10 switches just to see the effect of routing these grounds to different places .
the lifts will give you night and day resuslts , one off / one on , or vise versa or both .
try the seperate power ground , and the seperate audio ground ,
if you have problems , then move to seperating them etc.
