Potato Cakes
Well-known member
Hello, Everyone,
I have been working on a 1073/1290 style preamp board for my own studio for a couple of years now and finally had a first batch made. However it has a couple of errors and doesn't fully function how I intended so I am having to do a Rev B. The preamp does work perfectly if two traces are cut and a resistor and cap are added. It has a fixed HPF, polarity, 48V, and impedance select all built on the board it self. It also has a -inf to +6 fader, which can be omitted if desired. Boards are 8" x 3.3" which 8 channels can fit in a 2U case with an external power supply. Large heatsinks are accommodated as this can be run on +48V/0V, which makes typical heatsinks for this circuit run very hot. I had originally designed this to be powered by a +/-24V supply and this board still can be but there are a couple more considerations that must be taken into account to do so.If using a bipolar power supply there is an on board negative voltage regulator to forward bias the circuit. Either an Ed Anderson 10468 or a Carnhill VTB9045M can be mounted directly to the board. Fiber optic push button caps used for the LED indicators for each of the switches. All of the LEDs are red. Also has an insert point to add a compressor, EQ, etc if so desired. Gain is set 0-65.
Potentiometer shown in photo is a State Electronics Series 88. Other dual gang pots can be used but will more than likely have to be wired off board.
I was going to toss out this whole lot but since I did build a couple of these boards and know that it and does work with a couple of minor alterations, I decided to offer them here as it is an easy way to build this great sounding circuit with minimal off board wiring.
$17 per board and that includes PP and shipping to lower 48. This will be only time I offer these as the Rev B boards will be for my own studio use and clients.
Thanks!
Paul
EDIT: Forward biasing has to be done off board with these Rev A PCBs. Also for clarification the on board metering circuit does not work. This is part of the "does not fully function as I intended" sentence above. The preamp does still work perfectly with the previously mentioned minor alterations. Metering is not part of the preamp audio path and is not needed for the preamp work.
I have been working on a 1073/1290 style preamp board for my own studio for a couple of years now and finally had a first batch made. However it has a couple of errors and doesn't fully function how I intended so I am having to do a Rev B. The preamp does work perfectly if two traces are cut and a resistor and cap are added. It has a fixed HPF, polarity, 48V, and impedance select all built on the board it self. It also has a -inf to +6 fader, which can be omitted if desired. Boards are 8" x 3.3" which 8 channels can fit in a 2U case with an external power supply. Large heatsinks are accommodated as this can be run on +48V/0V, which makes typical heatsinks for this circuit run very hot. I had originally designed this to be powered by a +/-24V supply and this board still can be but there are a couple more considerations that must be taken into account to do so.
Potentiometer shown in photo is a State Electronics Series 88. Other dual gang pots can be used but will more than likely have to be wired off board.
I was going to toss out this whole lot but since I did build a couple of these boards and know that it and does work with a couple of minor alterations, I decided to offer them here as it is an easy way to build this great sounding circuit with minimal off board wiring.
$17 per board and that includes PP and shipping to lower 48. This will be only time I offer these as the Rev B boards will be for my own studio use and clients.
Thanks!
Paul
EDIT: Forward biasing has to be done off board with these Rev A PCBs. Also for clarification the on board metering circuit does not work. This is part of the "does not fully function as I intended" sentence above. The preamp does still work perfectly with the previously mentioned minor alterations. Metering is not part of the preamp audio path and is not needed for the preamp work.
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