Members ksl Posted January 10, 2020 Members Share Posted January 10, 2020 Good day all~~ Before I bring my modded MASCO MA25 over to my tech, I'd like to be able to show him on paper what a Vox-type contoured circuit looks like, as in what type of pot, etc., a 'Cut' control,,, that not only can cut highs, but offers a low cut, all in one pot, possibly concentric...? The Masco has only a single basic hi cut/low pass tone control, and with no need for more bass this amp, I'd like to do something flexible, different, & with an interesting sweep. Any help, diagrams by PM or posted here on this thread, if permitted, would be greatly appreciated. Thanks in advance. Kenny kslewitt@gmail.com Link to comment Share on other sites More sharing options...
Members WRGKMC Posted January 10, 2020 Members Share Posted January 10, 2020 I'd need to see the schematic for that Masco before telling you if its even possible to wire them the same. As a novice your knowledge is limited to the knobs of the front of an amp and dreaming of how you'd like it to sound but actually wiring a circuit to sound the same isn't always possible. In an amp like the AC30 the treble and Bass run in parallel circuits and are amplified with their own gain stages. That's much different then an amp that has a simple passive roll off tone filter like many of those museum pieces used to have. Some of that vox tone comes from the power tubes used too. Early Vox amps used a tone control and it wasn't placed were most put them in the preamp circuit. They placed them after the phase inverter in the power amp circuit which is quite unusual. Its also probably the reason so few vintage Vox amps survived. The first repair shop I worked in had dozens of vintage Vox amps abandoned by customers. They had unstable power amp design and when the power tubes went it typically gutted the power amp and transformers making it too expensive for people to repair so they'd abandon their amps to the shop instead of paying the diagnostic fees. In any case this site has some tone circuit diagrams you might want to use. http://www.voxshowroom.com/uk/amp/ac30_tb_hood.html Link to comment Share on other sites More sharing options...
Members ComingApart Posted January 20, 2020 Members Share Posted January 20, 2020 from the sewatt forum. Link to comment Share on other sites More sharing options...
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