No, not tubeless, just one tube less... 

The filaments of the rectifier tubes and triodes consume a lot of power. In total, 70W. In my transformer drawer I found a big transformer, with secondary taps of 23V, 24V and 25V. Therefore, I decided to work with strings of 4 tubes in series. Being all E-series tubes, 4 x 6,3V = 25.2V would fit well enough with the 25V output of the transformer. So, 4 strings of 4 E90CC's and one string of 4 EY88's. Although I needed only 3 EY88's in my design, I added one extra, doing nothing, just hanging around in the corner as a dropper tube. 

While gradually realizing the No-Si Clock, I realized that I would need some kind of mechanism to set the time initially. I came up with a switch with three positions: one normal position, one position in which the minutes tick switfly by and one position in which the hours pass by. But where am I going to put the switch? then I remembered the useless extra EY88. If I could do without that tube, I would have a place to put the switch. The solution I ended up with is to use not EY88's, but PY88's. These were used in series configuration, directly connected to mains voltage in tv sets of the day. They officially require 26V filament voltage each, so instead of stringing them in series, I could just use 3 of those, connected in parallel to the transformer's 25V. They will also work on a volt less.

Now I have room for my switch and additional advantage: the power consumption drops by almost 10W (6,.3V×1.55A).

Photo: The time adjust knob sits where a useless EY88 used to sit. You can see remaining three PY88 rectifier diodes. The switch on the far right may be the one I am going to use.