About wire forget the teflon ! use only stranded tinned copper wire with pvc isulator.
A very good quality stranded tinned copper wire could be buy directly from E-Z-HOOK that carries an extensive line of fine stranded and extra flexible wire.
The output transformers used in this project are the new Lundahl with amorphous C-core for the best sonic performances.
The LL1660AM/10mA has been configurated with the primaries in parallel (pin 13,16,18 e 21) to have a correct gap for a 20mA anode current.
In this configuration the LL1660AM/10mA have a primary inductance about 31Henry so the E182CC with a Ra about 2Kohm will give a ft(-3dB) = Ra / ( 2 * 3.14 * L) = 2000 / ( 2 * 3.14 * 31) = 10Hz (-3dB).
A valid alternative to the E182CC are the R5842 Raythoen and the D3A Siemens.
To get the max sonic performances and very long vacuum tube life has been choised slow turn on power supply for the filaments uning a common LM317 and a virtual battery operation power supply for the anodic using a power mosfet.
For this power supply I have used the R-CORE model R26-90 by DiyClub.Biz with primaries 2 x 115v and seconaries 0-150v(0.2A) + 2 x 0-9v (1.1A).
I have used in all the measurements the Clio system by Audiomatica with the Transit by M-Audio to use the USB port of my portable pc (instead of the PCI audio board) and with the Audiophile USB by M-Audio to have a spdif ouput.
The frequency responce is about 20 - 14000Hz at -1dB and 20000Hz at -3dB.
The output impedance is about 2200ohm with 2 secondaries in parallel and it could be about 1000ohm with all the secondaries in parallel but reducing the output level to 1Vrms.
It is very easy get a balanced outputs if it is necessary.