Need advice on my EZ1290 board remake

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nano_lee

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Jun 30, 2021
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Location
North Carolina
I started a project a coupe of weeks ago. I wanted a compact single channel neve clone just for personal use. So I bought a "one-shot" chassis from Seventh Circle Audio. I love how small this board was, and how the transformer all fit on the board. However, I didn't have the money for the N72 kit so I decided to try and redesign Martin's EZ1290 circuit, and fit it inside of a "one-shot" chassis. This seemed to pose many challenges for me, because I am not an engineer. I have some novice experience in guitar amps, but that's about it. I used an electronic cad program called KICAD to make the PCB. I had to make my own footprint for the Grayhill switch using the dimensions from the Grayhill datasheet. Here is a list of the changes I had to make in order for the EZ1290 build to fit in the "one-shot" chassis.

* I used the VTB1847 output transformer instead of the VTB9049.
* I used the VTB9045M input transformer instead of the VTB9045.
* I changed all of the caps to radial style to save room, I went with Nichicon for the whole board.
* I made the BA183-NV stages separate from the board, so that they can stand up vertically. (just like JLM Audio's mini 1290 kit)
* I ripped out the DI and power board of the one-shot chassis, and made my own bridge rectifier, filter, and voltage regulator. I put this power section on the board.
* I used the 24VAC wall wart that comes with the one-shot chassis as my power transformer.
* I changed the reference numbers for all the parts, and made my own BOM. Martin's would not work with my CAD program. All values are the same though.
* Martin has jumpers on his board to deal with tracing problems, instead of that, I opted to use 0 ohm resistors. They look weird on the schematic but I had no choice.

Schematic
 
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