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Vox AC4TV mods

Started by madbean, June 04, 2014, 04:38:28 PM

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madbean

I did some mods this afternoon to the trusty old AC4TV and they turned out quite nice. Here's what I cobbled together from suggestions on the internets.

Replace the stock Sovtek tubes. I went with a Tung-Sol EL84 and a JJ 12AT7. The AT7 is lower gain than the AX7, but I got one of those too in case I change my mind later.
C5 - bumped from 4n7 to 22n Orange Drop 630v.
C6 - switched to 22n Orange Drop 630v.
C4 - bumped from 220pF ceramic to 500pF Silver Mica.
C3 - bumped from 4n7 to 10n Orange Drop, 100v.

On order: Weber 10" Blue Pup to replace the stock 10" ceramic. I may also cut a new port on the back of the amp.

End result: beefier, some more headroom, I think, and a more useable tone control. It really does sound a bit thicker due to replacing C5. I still run the tone control on the dark end, but there is more balance and range. I might go back later and add a switch to put another small cap in parallel with C3 to go even darker. I also might replace C18 with an Orange Drop just for the mojo at a later time. I don't have any rated for 400v+ right now, only 100v.

I'm pretty stoked with the new tones. The component changes are fairly inexpensive and the speaker is reasonable ($95). But, the jury is still out until I swap that speaker. So far, so good!

madbean

BTW: the PCB is super cheap. You have to be really careful not to burn any pads up when you desolder. I pulled a partial pad even while being gentle.

Joachimsolborg

Can I use 600V orange drop for C5 & C6?

madbean