Preamp schematic for "mic" needed

[freddbro]

Perhaps my request for a Schematic for a DIY "Mic" preamp is
not in line with the topic of discussion here, Hope it's admissable..
I have been "Googling" for one and the GE-UPX 003 might suite my needs..
The resistor values can almost be figured out However, there
is NO value for the transformer outputs.. I intend to mostly use this
PreAmp to increase the "Drive" of a "Mic" into my Tube "Ham" Radio
Transmitter.. Any Advise would be helpful.. Thank You..

[Coffee Phil]

Hi Freddbro,

Im pretty sure that the GE circuit will work fine but it is a bit overkill.
The mic does not require EQ (someone smarter than me should explan why magnetic phono pickups are velocity responding but magnetic mics respond to sound pressure)

If you really want to build this to avoid "sand" in your ham rig the transformer secondary outputs required are 6.3 volts center tapped @ greater than 300 ma and ~ 100 volts at more than 50 ma. Use a silicon diode rather than a stinky, poisonous selenium.

Perhaps my request for a Schematic for a DIY "Mic" preamp is
not in line with the topic of discussion here, Hope it's admissable..
I have been "Googling" for one and the GE-UPX 003 might suite my needs..
The resistor values can almost be figured out However, there
is NO value for the transformer outputs.. I intend to mostly use this
PreAmp to increase the "Drive" of a "Mic" into my Tube "Ham" Radio
Transmitter.. Any Advise would be helpful.. Thank You..

[Coffee Phil]

I should add that If you are not "sand phobic" and want a simple circuit to do the job, give us some info about the mic, the gain which you need and the audio input impedance of the transmitter and I or someone else here can come up with a schematic.

Phil

Hi Freddbro,

Im pretty sure that the GE circuit will work fine but it is a bit overkill.
The mic does not require EQ (someone smarter than me should explan why magnetic phono pickups are velocity responding but magnetic mics respond to sound pressure)

If you really want to build this to avoid "sand" in your ham rig the transformer secondary outputs required are 6.3 volts center tapped @ greater than 300 ma and ~ 100 volts at more than 50 ma. Use a silicon diode rather than a stinky, poisonous selenium.

Perhaps my request for a Schematic for a DIY "Mic" preamp is
not in line with the topic of discussion here, Hope it's admissable..
I have been "Googling" for one and the GE-UPX 003 might suite my needs..
The resistor values can almost be figured out However, there
is NO value for the transformer outputs.. I intend to mostly use this
PreAmp to increase the "Drive" of a "Mic" into my Tube "Ham" Radio
Transmitter.. Any Advise would be helpful.. Thank You..

[1200y3]

Ironically, I learned most of what I know about Hi-Fi, especially tubes (like 211's and 838's) from the "Handbook".

I would follow guidelines from the proper amateur radio handbooks, although it may be difficult to find anything that interesting in the newer handbooks.

Tube type finals (such as 6146B/12BH7) may be still employed in modern digital systems up to the recent times, but the most sophisticated IC and transister circuits were used to make the outputs roar.