The Fenton Project V

Here we have the chassis drilled, punched and the first few bits mounted. Came up with a very nice NOS ceramic socket for the rectifier tube. Those get hot and this one won't care. Nice silver plated contacts, too. So it's time to start connecting stuff. This will work in layers, starting with heaters and primary power supply.

And, a quick look underneath. What photo's can't show is the thought process behind laying this out. I tend to spend a lot of time thinking on these things, scribbling, shoving parts around and trying to reach the best of all the compromises involved. And the longer you go at that, the closer you get to very conventional, established practice. But, every detail you can improve does that much more to lower the noise floor and improve reliability and tone.


Once you mount the Power Transformer and start wiring things up the orientation of the tube sockets makes sense.




The basic rule of heater wiring is that you want to keep it away from signal wires. The two main approaches are to either keep the signals near the chassis and the heaters up in the air as in Fender amps. The other, more often British approach is to keep the heaters low and away from the signal circuits. Here they run to the corner of the chassis where the only wiring they'll be near is the Output Transformer primary and secondary. Neither is susceptible to noise pickup.



That big terminal strip is sort of a divider between the dirty and clean electrical environments inside the amp. On one end is the power cord "safety" ground and on the other is the chassis ground for everything else -- on one side is the raw AC and the secondaries of the power transformer on the other is everything else in the amp with the HV to the rectifier sneaking past.


Stay tuned for our next installment when we start with the next layer of wiring and connections.