5E3 Lunchbox Head Parts

I decided to pull the trigger on buying a power and output transformer for my 5E3 lunchbox head project after hearing that Classictone Transformers will cease operations after October 2020. I’ve used Classictone for my two other builds because of their upright project-style power transformers. I don't have the tooling to make a cutout for a laydown transformer, so I have only used upright power transformers so far.

 Classictone 40-18066 PT and 40-18022 OT

I did not come across any upright PT comparable to the 40-18066 that was in stock. The 40-18066 is an upright version of the 40-18017 laydown transformer, so I can use the Triode layout for transformer wiring reference. The 40-18066 does have a center tap for the 6.3V secondary, so I don't have to incorporate extra wiring to balance/elevate the heaters.

The 40-18022 is the standard 8kohm/8ohm 5E3 output transformer from Classictone.

Quick mockup of layout in CAD.

I bought the transformers before coming up with a layout this time. I had placed the PT and OT a little too close together on my Plexi build because I drilled the chassis before getting the transformers.

Hammond 1444-24 aluminum chassis taped up for drilling.

I need to buy some tube sockets, a Powercon connector, and I should be able to build this amp. I have already populated a turret board with Vishay metal film resistors, MKT1813 coupling capacitors, and F&T filter capacitors. I have decided to incorporate a negative feedback switch on an otherwise typical 5E3 build. I am thinking of using a 22k resistor and a 20k pot in series off the 8 ohm tap.

Double checking transformer layout prior to chassis drilling.