Welcome back Ianmedium !!!
just to mention, as the Marconi DL92 were never seen on eBay, you can buy the OSRAM DL92 instead, should be the same as OSRAM in fact was OSRAM / Marconi (i bought the two sets that were availabe some time ago, but ... ).
Did a lot of work in the meantime, but really occupied with my job at the moment (XPLOSIVE - haven't forgotten your tube).
For my "Highend TU-05" mod i spent months
- designing and optimizing the interface for the battery modules and the front panel, in fact changed the interface 11 times until i was satisfied.
- completely changed the arrangement of one set of modules to one PSU module, now they will have a backplane, each module can be exchanged separately.
Many ideas in my head i want to test or implement, so i postponed working on my "highend TU-05" at the moment, instead going the next steps starting to design everything else i need for a complete tube amp
- test of the input transformers
- design of the discrete voltage regulators for anode and filament voltages,
- mini modules with standard PCB connnector for the different voltage regulators
Made some test equipment needed:
- a four channel charger for small (4x up to 4 cells) Li-Ion battery packs,
- a test power supply for tube modules with 4x anode voltage PSUs (up to 80 volt) and 6 filament voltage PSUs, of course completely separated, no gorund to ground connections, to test all the tube modules i have or will build
For my portable "Dream TU-05" rebuild (original extended case):
- a really compact new double mono tube module
- reworked the two original TU-05 PSU boards to reduce the height
- larger but fitting output transformers to have more bass and more variable impedance settings (made them out of the disassembled and then recombined parts of my existing two original tu-05 output transformers and the two ones BMichels had sent me (thanks again for that) , the larger output transformers are a real improvement, not only somewhat deeper bass, but better matching the impedance of my DIY grado style headphones resulting in more detail, texture and better imaging)
- two 67,2 volt miniature anode voltage Li-Ion batteries made out of 2x16 Apple Ipod 1 batteries and 2x4 balancer boards with about the same size as the original tu-05 PSU boards so that they can be used instead of the original PSU boards (!)