Samuel Groner
Well-known member
Hi
I need a simple and cheap mic pre to record my singing lessons; mic is a dynamic one, PSU a +5 V from an old HD.
I took a design by Hood and tried to adapt it to 5 V ([removed]); however, I have trouble setting nice operating points. Base of Q1 and Q3 are OK, collector of Q2 and Q4 is not (< 1 V). Is there a way to set these collectors to ~2.5 V? Playing around with the resistor values did not help me.
How about biasing Q1 with more current for lower noise? Lowering R3 seems not to help that much?
R9 will be a pot, BTW.
Thanks!
Samuel
I need a simple and cheap mic pre to record my singing lessons; mic is a dynamic one, PSU a +5 V from an old HD.
I took a design by Hood and tried to adapt it to 5 V ([removed]); however, I have trouble setting nice operating points. Base of Q1 and Q3 are OK, collector of Q2 and Q4 is not (< 1 V). Is there a way to set these collectors to ~2.5 V? Playing around with the resistor values did not help me.
How about biasing Q1 with more current for lower noise? Lowering R3 seems not to help that much?
R9 will be a pot, BTW.
Thanks!
Samuel