Any thoughts on a topology along this line for a microphone preamp (may use something other than the AU7 but interested in the topology primarily at this point)? May also add a second gain stage. Connected as shown for single ended input and with the second cascode grid connected to the minus input signal for balanced mic input.
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Use either a 6dj8 or 6bq7, and maybe a source follower on the output instead of the cathode follower.
What are your desired goals of the circuit?
What are your desired goals of the circuit?
The possible project is a small combo amp for use with a microphone and possibly a keyboard. Would be looking to support typical balanced LowZ and unbalanced Hi Z dynamic or self powered condenser mics. Will be primarily a practice or small coffee shop type environment. Does not need to be recording quality or to support any exotic microphone styles.
Surely LTP halves voltage gain and doubles noise power? If so, the opposite of what a mic preamp needs.
Cascode eliminates PSRR. The opposite of what a mic preamp needs?
Cascode eliminates PSRR. The opposite of what a mic preamp needs?
Maida regulator then?
Or, perhaps 6au6 LTP instead?
Could get a little fancier and use an input transformer into a 12at7 that has a current source plate load, use the other half of the 12at7 as a cathode follower, of course this depends on what the output level of the Mic is, I'm not familiar with microphone specs.
Or, perhaps 6au6 LTP instead?
Could get a little fancier and use an input transformer into a 12at7 that has a current source plate load, use the other half of the 12at7 as a cathode follower, of course this depends on what the output level of the Mic is, I'm not familiar with microphone specs.
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> practice or small coffee shop type environment. Does not need to be recording quality
Then why _5_ triodes?
There are XLR-1/4" "converters" with transformers inside for less than the cost of a mike transformer. Typically 1:5 or 1:7. I used them a lot in your situations. Two plain/simple stages of 12AU7 is gain of 200. Gain over 60dB in one bottle and one jack.
Or would you rather wire complex circuits than make music? I can go with that too. But over-complex bugs me.
Then why _5_ triodes?
There are XLR-1/4" "converters" with transformers inside for less than the cost of a mike transformer. Typically 1:5 or 1:7. I used them a lot in your situations. Two plain/simple stages of 12AU7 is gain of 200. Gain over 60dB in one bottle and one jack.
Or would you rather wire complex circuits than make music? I can go with that too. But over-complex bugs me.
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