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.
I bought a Line 6 HX Stomp to get myself into the latest generation of hardware amp modelers. I decided to go with the HX Stomp over the Fractal Audio FM3. The smaller size of the HX Stomp is much more favorable at this point, but I do intend to try the Fractal Audio modeling one day.
I was a bit underwhelmed by the modeling in the Line 6 POD HD desktop for years, but started to warm up to its modeling recently. Before getting the HX Stomp, I was playing through the preamp models into a VST plugin chain: Ignite Amps TPA-1 power amp and impulse responses in Redwirez MixIR2. I also started using the POD as a hardware insert for its effect models in Reaper.
My main draw to a new hardware modeler was a standardized input into the digital realm. Gain staging is inconsistent between different brands of VST amp modelers. Furthermore, each interface manufacturer has their own line level input levels. My original reference setup was a Waves/PRS Guitar Interface (gain at minimum) into a Focusrite Saffire Pro 26 Line Input (maximum level +28dBu). I was recording bridge humbucker DIs with peaks at around -10 to -12 dBFS. Kazrog Thermionik amp sims required 6-12dB trims on the inputs, while Scuffham S-Gear required significant boosts (maxing out the input trim at +6dB). I was getting reacquainted with the recording unaffected DIs through the POD HD recently, and it warmed me up to the idea of the Helix family of modelers.
The HX Stomp allows me to record DIs on my desktop or iPad/iPhone at the consistent levels that are appropriate for the Line 6 amp models. Helix input levels were about 3dB lower than my Waves/PRS Guitar Interface - Saffire setup.
Reamp routing with the HX Stomp.
I can record an unaffected direct signal into my DAW while monitoring through the HX Stomp. I can then take the dry unaffected signal and reamp it through my amp using one of the the HX Stomp's loops to fine tune the sound. I like that this sort of reamping can be easily moved from location to location, with my iPhone serving as the DAW.
USB reamping comparison with real amp and Brit Trem Brt model.
I immediately gravitated towards the Brit Trem Brt model, as this sounded most like my Plexi amp build set to early Lead Spec (split cathode, V1b 0.0022 coupling cap, no V2a bypass cap) with no bright cap. Despite the differences in circuitry, the Treble, Middle, Presence, and Gain knobs were in the same ballpark. The behavior of the Bass knob on the HX Stomp did not scale the same way as the real amp, but I am able to dial in the two sources to be very similar. With the amp's bass on 2, the equivalent Helix setting is about 7. The Brit Trem Brt was modeled after a shared cathode '68-'69 1987 Tremolo with bright cap, which would explain the major difference. The noise floor is much better with the Helix model when compared to the real amp, which is a major plus.
A comparison between the HX Stomp Brit Trem Brt and Brit Trem Nrm models against my Plexi buildwith the bass set on 0.
I have a Dunlop DVP4 mini expression pedal and Mosky single footswitch assigned to EXP1 and FS5 inputs respectively. To get the DVP4 working, I had to flip the internal dip switch to Expression, and set the HX Stomp's expression polarity to Inverted.
