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  • If a single ended 5 watt amp aint enough grunt, then the GT18(watt) 'Paydirt' circuit may just offer what you crave. The GT18 'Paydirt' is a cathode biased, 2 x EL84 output tube, circuit in push-pull. The tone is ball-park JCM800 with some very distinct advantages. The GT18 'Paydirt' has switchable clean/crunch channels both of which have their own input triodes in addition to their own dedicated gain pots. The GT18 'Paydirt' also contains the active Treble/Mid/Bass Baxandall tone-stack circuit found in the GT5 amps.


    The GT18 'Paydirt' has bucket loads of gain with a clean channel that is both chimey and decidedly non-flubby. The clean channel gain pot starts to gently break up at about noon, so you can take it beyond the brink when needed. The crunch channel provides the GT18 'Paydirt' with warm distortion and an abundance of 2nd order harmonics. The dedicated gain pot of the crunch channel, coupled with a tone-stack full of generous sweeps, enables you to easily dial in your signature overdrive tone.


    With EL84 output tubes and a 'cold clipped' preamp, I guess you could envisage this amp lying somewhere between a Vox and a Marshall, however a 'Voxhall' it is not. It was designed as a powerful 80's blues/rock workhorse (and it certainly achieves that in my opinion), however the clean channel was a very pleasant surprise as it surpassed my expectations by a long shot. When I play this amp, I find it hard to turn it off, and that is a winner for me.




    The GT18 ‘Paydirt’ 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 ‘Paydirt’ Full Plans Pack is designed for those who desire an epic 80's do-it-all amp that can go from bedroom level to band practice volume. This one will challenge both your tool rack and patience so be sure to first check out the comprehensive video series of the GT5 Halcyon build. Also check out the Blog page if you want to begin the rabbit hole of theory. Buy the plans by themselves, or pick them up in the 'Entire Plans Collection' Package.


    Rest Easy


    I absolutely understand that tube amps dance to their own tune, so if things go up in smoke or implode with a weird whistle, for whatever reason, be sure to grab yourself a ‘no questions asked’ full refund!

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

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