top of page
  • Is 50 or 100 watts of tube power a little bit too much for band practise? Do you want to keep that BIG 50 watt fixed-bias tone without the 'Noise Police' knocking at your door? Enter the GT18 'Overburden'. A No-Faffing-About, fixed bias, push-pull amp that can operate with either 6V6 or 6L6 power tubes.


    With 6V6 tubes, not only can you take advantage of a lower overall output, you can either dial in the vintage raw grunt of the 80's, or ease things down to 50's blues territory. With over 400V of rectified DC on the plates, you can swap in 6L6 tubes and be rest assured that the output will increase producing that big fat tone that 6L6's are famous for.


    The GT18 'Overburden' shares a similar topography to the GT18 'Paydirt' with switchable clean/crunch channels, both of which have their own input triodes with dedicated gain pots. The clean channel has a heap of headroom, so you can play Hendrix all night long. The GT18 'Overburden' also boasts the versatile 'ELAMS' active Treble/Mid/Bass Baxandall type tone-stack circuit found in the GT5 'Halcyon' and GT18 'Paydirt' amps, so fiddle and tweak till the cows come home.


    Don't get me wrong, I love a bit of sag in all the right GT18 'Paydirt' places, however an extra electrolytic filter capacitor in the preamp section enables the GT18 'Overburden' to deliver the kind of tight bottom end your wife would be proud of. I'm a fan of the 6L6 tube, however I enjoy the crisp tone of 6V6GT so much that I think they'll be staying in there for the foreseeable future. 




    The GT18 ‘Overburden’ full plans pack includes:

    • a schematic/circuit,

    • detailed layout diagrams accommodating for either a 120v or 240v mains primary,

    • a detailed turret board layout,

    • a key for the colour coded turrets,

    • a transformer cable termination guide,

    • chassis layout diagrams of both top view and bottom view,

    • a front and rear chassis panel layout,

    • schematic codes,

    • a resource item list, and

    • tone stack frequency guide.


    The GT18 ‘Overburden’ Full Plans Pack is for those who want to build an amp that showcases the best decades of rock and blues. The layout has been both upgraded and simplified to include fewer shielded cables and superior routing. As with all amp builds, take it slow and be sure to first check out the comprehensive video series of the GT5 'Halcyon' build. Purchase the plans by themselves, or pick them up in the 'Entire Plans Collection' Package.


    Rest Easy


    If life gets in the way of fun or you're in too deep and things don't pan out the way they should, for whatever reason, be sure to grab yourself a ‘no questions asked’ full refund!

    W.I.S.C GT18 'Overburden' Full Plans Pack

      bottom of page