I used schematics and info from these sources as a reference
I then designed the pcbs to fit all of this into a 1U rack case and accommodate for the components I used.
I used a transformer from tube-town.de which is originally designed as a replacement for an Engl 520 preamp, and it works great.
The sound is really great and alive, and the controls are very effective.
It works wonders on guitar too, giving the nice Fender treble sheen.
For good signal-to-noise you should take extra care with the wiring, applying the usual recipies: star grounding, short cables to the pots, shielded wire for the signal path, twist the AC heater wires, and not having psu wires parallel to signal wires.
Also I found out the output was high and adding a volume pot to my power amp lowered the noise a lot.
The preamp coupled with my DIY mosfet 2x70W power amp, fedding an Ampeg 15″ cabinet – rumble in the
jungle neighbor’s ceiling
One channel with the 12ax7 socket fitted on a right-angled pcb to fit inside 1U case. PCB is mounted using right-angle brackets.
Here are the layouts I did for both the preamp and the PSU, with extra consideration given to the routing to minimize noise, with high resolution pdf files for the PCB designDownload