All new Ground Zero “Add-a-stage” PCB - add a gain stage to your amp the easy and clean way

RedPlated

RedPlated

Well-known member
I just designed this PCB for adding gain stages to my Marshall mods. It’s a self contained board that has a complete tube stage circuit, extra 12ax7 tube, separate filtering node AND a relay for switching the stage in and out of circuit. All in a board that’s the same size as an average LND150 fx loop board.

This PCB is ground shielded and laid out for the best possible circuit path with low noise. It will accept AC or DC tube heaters, can be configured with whatever values you choose and uses a PCB mounted tube socket with standoffs for additional strength and resistance from broken solder joints.

I’ve installed 5 of these in amps already and they are spectacular. Easy to install, clean wiring and nice and quiet. I even fit one into a 1987x.

All my mods will have these from now on. I will also make them available for purchase separately to anyone who wants a convenient way to add a gain stage to their amp. I even added a hole in the center of the tube socket to function as a template for drilling the hole.

 

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Very cool!
Any plans for any specific 'kits' or loaded boards for say, "Add a stage to a 2203/2204" or similar?
Also, can you wire up the two triodes independent/separate?
 
SpiderWars said:
Very cool!
Any plans for any specific 'kits' or loaded boards for say, "Add a stage to a 2203/2204" or similar?
Also, can you wire up the two triodes independent/separate?
Click to expand...

Yes I plan to offer them as loaded or unloaded.

This one is designed to only use one triode. It would be nice to have the option of using both sides of the tube, but then the board becomes bigger and more complex.

I think the most common application is adding one additional stage. Not many designs add two additional stages. Maybe if there was enough demand I’d consider making one.
 
wIsEbLooD said:
I need one.
Using a hot mod at the moment and I really like it.
Click to expand...
Those are easy and convenient. It’s nice to be able to tune the extra stage to the amp, though. Plus, the Hot Mod inserts the extra stage in-between stages where the Add-a-stage goes up front before all the stock stages, in a more traditional position.
 
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