Minion
Well-known member
Hi Folks, I am designing a Transformerless Mic preamp that has an Optional Tube Stage useing a couple Power amp pentodes to add a Bit of Color to the sound but I am haveing a Problem if I will need some sort of Impedance buffer after the Tubes before going into the NE5532 for Ballanceing??
Here is the basic Topology of my design...It has a Transistor front end which then goes into a INA103 Instrumentation Opamp which then goes into the Tube stage (6418 Submini Power amp pentode tubes) and after the Tube stage it goes into a Ne5532 for Creating a Ballanced output and then to the Output....
What I am wondering is I should use a Fet Impedance Buffer after the Tubes to lower the Impedance before the Signal goes into the NE5532??
The output impedance after the Tube stage is Close to 1M ohm which I think might cause problems for the NE5532 so I was thinking of useing a Fet Impedance Buffer to lower the impedance for the NE5532.....
And if I do need some sort of Buffer can someone Point me to a simple Buffer design??
Thanx a Lot!!!
PS: I know poeple from the Golden ears Brigade will say "You should use an Ouput Transfermer after the Tubes" But this is absolutly NOT an option for me because of the Cost of Output transformers and the Space requirements I have.....
:thumb:
Here is the basic Topology of my design...It has a Transistor front end which then goes into a INA103 Instrumentation Opamp which then goes into the Tube stage (6418 Submini Power amp pentode tubes) and after the Tube stage it goes into a Ne5532 for Creating a Ballanced output and then to the Output....
What I am wondering is I should use a Fet Impedance Buffer after the Tubes to lower the Impedance before the Signal goes into the NE5532??
The output impedance after the Tube stage is Close to 1M ohm which I think might cause problems for the NE5532 so I was thinking of useing a Fet Impedance Buffer to lower the impedance for the NE5532.....
And if I do need some sort of Buffer can someone Point me to a simple Buffer design??
Thanx a Lot!!!
PS: I know poeple from the Golden ears Brigade will say "You should use an Ouput Transfermer after the Tubes" But this is absolutly NOT an option for me because of the Cost of Output transformers and the Space requirements I have.....
:thumb: