Often referred to as the “marshall”, “plexi” or “tweed bassman” mod, our “Tweed Preamp” mod re-voices one channel of your vintage Fender for a warmer, thicker tone with more midrange emphasis. This lends itself to earlier breakup than the standard Fender preamp circuit. Easy mod to perform, and very effective. Do this mod in one channel of your two channel Fender, and it’s like having two different amps in one. Very handy if you use different guitars with different pickups, play different instruments, or just want a different tone at your fingertips. We use Mallory 150M series caps with the outside foil marked for better tone & performance. If you have reverb in both channels (or no reverb), you can use both channels at the same time for an extra fat gain boost! Works great with an A/B/Y switch!
This mod works exceptionally well with our “Bright to Boost” mod for even more natural overdrive!
Please note: If you are modding the bass channel of a bassman head, the deep switch is already wired as a “boost” and will be more effective paired with the tweed mod. An upgraded boost cap will be included in the silverface kits. For blackface bass channels, that blue “molded” cap is the best you can hope for – keep it in there!