May 28, 2019

First crack at a Point-to-Point layout

Inspired by Rob Robinette's site and using DIY Layout Creator I came up with a layout for my Two Stroke Amp Head.

The design is based on 12 X 8 X 2 Hammond aluminum chassis.
The black and grey twisted pairs represent a shielded cable.
I am using a separate  preamp bus and power-amp bus.
I am trying to keep the input away from the power transformer.
I am trying to keep the tubes close to where they are needed.

The main modifications from the original schematic are:

Mod-1. Added a 470Ω screen resistor to V2 (see forum discussion), in my schematic this is R15.

Mod-2. Added some SPDT switches to pick 3 of the 4 output transformer impedances.

Mod-3. Based on Uncle Doug's videos, some helpful forum members, and Merlin's book , the 68KΩ grid stopper on V1 should be smaller. Fender amps would have the equivalent of 34KΩ and Merlin suggests that 10KΩ + 680pF capacitor will be quieter.  I have not updated the layout yet but I am considering it.



P2P Layout

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Two-Stroke Amp Head: Goals and Rationale

I want to build a head version (of the 2nd revision) of Dave Hunter's Two-Stroke Amp from his book.

I am not interested in a kit because:
  • living in Canada, kits are expensive due to shipping, importing, etc
  • I am lucky enough to have good local suppliers, e.g. NextGen, Spaceman, etc
  • I am not in a hurry and I will learn more by sourcing my own stuff ... and making mistakes
  • I want to make a head, not a combo

I want to make head instead of a combo because:
  • I have a speaker cabinet
  • I am interested in different cabinet styles and speakers so I'll probably build a couple variations
  • I don't have any experience making cabinets ... yet, but one thing at a time

I am interested in the Revised Two Stroke because it's a simple, flexible design based on a classic:  Fender Princeton - 5F2A.

The Two-Stroke allows you to use a variety of preamp and power tubes.