today the two tango output transformers arrived!
i coudn't resist to connect them to the tu-05 to have a first impression if they fit and how they sound:
it looks really improvised, the cheapest wires you can think of, but let's speak about sound.
the primary impedance is 5 KOhm, also 3,3 and 1,7 KOhm primary impedance is possible. on the secondary side you have the choice of 4-8-16-32 Ohm impedance.
the transformer fully fits the specs to be used with the tu-05, only the 1,7 KOhm impedance is and sounds too low as the standard output impedance of the dl92 tubes is about 8 KOhm.
so at first i connected the output transformers with 5 KOhm primary impedance to the tu-05 and secondary 8 Ohms to my DIY grado style headphone.
I HAD NEVER THOUGHT OR DREAMED OF THAT THIS WOULD BE
SUCH A GREAT IMPROVEMENT !!!!!
whatever i missed up to now (listening with the rft df97 - philco 1s4 combo) is now there!
soundstage width and depth are increased to a level i never heard before, also pinpoint imaging, localisation, the feel for the space, the air around each voice, person, instrument, the precision and effortless presentation independent of the volume level... the tu-05 now again plays in a different leaque, a totally new amp.
deep bass is there, the bass extension, quality and texture is wastly improved.
i must say i am blown away, so if you can, get new output transformers.
also now it is possible to use the hd800, but to match the hd800 impedance you have to use the primary 1,7 KOhm impedance of the output transformers, and that is definetely to low for a single dl92 tube to sound excellent, which means for my mod i will design a tube output stage with at least 2 DL92 in parallel to decrease the tube output impedance.
i have to test how the transformers sound with my low impedance headphones / iems (akg k3003, fad pf viii), just started to listen to the akg when the battery of the colorfly c4 was empty.
i have the felling that 5KOhm primary / 4 Ohm secondary impedance is not as good sounding as the 7 KOhm primary / 8 Ohm secondary Impedance setting possible with the original output transformers.
so if you can get good se output transformers with primary 5 and 7 KOhm and secondary 8 ohm, give them a try.
as i also ordered much cheaper but better se output transformers (a pair for just Euro 75,-) fitting this specs and especially modified for the dl92 tubes (smaller gap), i will test them and post some results after they have arrived.
as summary i am in heaven now, my DIY grado style headphone sounds better than ever, for me superior to the hd800 in nearly every aspect, so now waiting for the new case and the second internal power supply to start modding.
