Salas DCG3 preamp (line & headphone)

diyAudio Chief Moderator
Joined 2002
Paid Member
Very near voltages on +/- rails, still not above 18V not to jeopardize the servo opamp. But maybe we can moderate them. How many mV drop between legs R1,R2 on each? mV/33R will answer mA. Lets see if we can drive the Leds to lower Vf total by upping those current limiting resistors. What value RxJ RyJ you installed by the way?
 
Checking resistor bands, am I right that brown black black gold is 10R?


1000013259.jpg
 
diyAudio Chief Moderator
Joined 2002
Paid Member
It is 1R each, with drop of 5mv across both
If talking about the pictured location, those are RyJ & RxJ. 5mV/1Ω=5mA. Right on design target. It seems that the Bargraph Leds are happier for Vf in your batch. Nearing 18V output. Still below max rails spec. R1 & R2 33R limit J1 & J2 IDSS to 5mA and feeds it to the Leds. If you replace all four R1 R2 with 68R you lessen ma and Vf for all the output voltages to back off a little. The R1 R2 locations can be seen in post#2 first picture for the dual mono PSU sections and polarities.