After some success with the Trident mic preamp (AKA the Revox A77 Preamp), I thought I might try another section of the console - this time the EQ / Channel output amplifier.
It looks interesting on LTspice, as towards the end of the gain range, you get a distinct bump in the mid-range. At the moment I've left the values on LTspice fairly stock, except of course for running at 9v.
Like other projects - if successful, I'll post a working vero layout. If not... well, I'll move onto the next one, or better yet, finish the growing number of incomplete projects that I have.
I’m calling it the Sea King for the moment, which is perhaps a bit presumptions, as I don't even know if this will work well enough to warrant a name.
TRIDENT A-RANGE CHANNEL OUTPUT AMPLIFIER SCHEMATIC
LTSPICE
working notes reference schematic below:
- input and output caps can be smaller
- Reducing C13 reduces bass
- Increase C12 to reduce highs
- C15 can be as low as 10u without any real impact (in spice anyway)
- gain pot may need to be quite small - def not 5k, more like 500ohm
- changing R18 moves the mid hump / and low end to some degree, as well as some change to gain, might be interesting as a pot (1k resistor + 20k pot)
- Try a single diode for biasing, R24 may not be required (low value trimmer on original)
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