Hi everyone! Just wanted to share the mods I'm doing to my Toft ATB board!
I guess I went a bit nuts with it, but I decided to design new PCB boards for the input channels, the subgroups and the master. My pcbs still have the trident style EQ, but the preamp and 2nd stage have been updated to replicate the API boards from the 70s. So, I'm basically substituting my input channels for API 528/536 modules. I've also done a number of upgrades to the boards like adding a switch to activate/deactivate the now BALANCED Insert, a switch to add/eliminate the second output transformer on each channel, another one to select the EQ before/after the insert point, or in the subgroups (though I've still not tested those), an inductor based HPF.
Attached is the schematic and layout for the Input channels. If anyone wants to mod their own console, I'm accepting orders on those PCBs and plan to finish the subgroups and master pcbs soon.
Hey @makewar, my Toft ATB 24 is getting pretty noisy in the Master and Subgroupsection. Could you please post these Mastersection schemetics? I´m not the one whos gonna repair them since i dont have a single clue what to read on those schemetics but i have a guy who is willing to do it for me. Thank you very much.