DIY Valve Amp – Planning Modifications

I’ve not yet started the build of the amp but I’m already planning out the modifications I want to make to it. First off is a way to overdrive the power stage of the amp at lower volumes. Over the past couple of weeks I’ve tested out some 5w valve amps and was surprised by how loud they were. If they’re getting wound up then it’ll certainly be too loud for playing at home. So far I’ve identified three potential solutions to this.

  1. Power Scaling – From what I gather this essentially reduces the high voltage DC supply to the amp’s power stage allowing it to overdrive at lower volumes. Mastertone supply a kit that looks to represent decent value.
  2. A different output valve – Considering having a 6n1P valve as a switchable option to the usual EL84. This drops output power from 5 watts to approximately 1 watt. See the Options Guide at the excellent Power output can even be dropped to 0.5 watts by only using half of the 6n1P.
  3. Attenuation – This is probably the cheapest and most simple option, but then again is the one that probably compromises the sound more than the others. In essence it sits between the amp and speaker and reduces the power passed through.

Other potential modifications (in reducing likelyhood of getting done) I’ve considered are

  • Replacing the on/off and standby switches with a single on/standby/off switch
  • A tone bypass switch
  • Adding an effects loop
  • Adding a spring reverb
  • Built in tube screamer and/or tremelo

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