Emission Labs PX4-Mesh - Parret Par

The EML PX4 mesh tube is equivalent to the 15 Watt Version of the historic PX4 by OSRAM and MARCONI, apart from the heater current. The EML PX4 has higher heater current. Since the historical data sheet gives no numerical value for Gm and Rp under normal bias conditions, the values for Gm and Rp were extracted from the historical tube curves.

Guarantee

The first owner can register the tube at the Emission Labs ®website, to participate in the 5 years guarantee program.

Description:

We quote from the OSRAM data sheet: "The PX4 is a Directly Heated Power Triode for the output stage of receivers and amplifiers, where a considerable output power is required with a maximum anode (to Grid) Voltage of 300 Volts. For this purpose the tube has exceptionally good characteristics, and is particularly suitable for operating moving coil speakers at large volume without distortion"

Application:

In accordance with the historical datasheets, we say EML PX4 is most suitable for applications for medium output power. Achieving lowest distortion is possible with historical tubes, or new build tubes, by choosing the load impedance slightly above the original recommendations of OSRAM. The Output Power can well achieve 4 Watt at full signal, when going to a Load impedance of 3...4k. Already at marginally lower signal, distortion begins to drop fast.

There is some resemblance with the 2A3 or AD1 tube, which can also operate nicely at 250V 60mA, same as the PX4. Yet PX4 is a tube with somewhat higher impedance character, positioned somewhere in between 45 and 2A3. The sound of the PX4 comes closer to a 45, but the output power comes closer to tubes like 2A3 or AD1. This makes it a very good tube for high efficiency loudspeakers, similar to what OSRAM wrote already, a long time ago.

Filament / Heater:

The EML PX4 uses a heater current of 1.5 Ampere, vs. only 1 Ampere for the historical tubes. The EML heaters are specially constructed to have lowest possible hum, which is lower than historical tubes. Altough the is specified for AC or DC heating, for best results we recommend DC heating. This becomes increasingly important if a tube is used for very high efficiency loudspeakers. Please note, for all directly heated tubes, the superioir DC heater schematic is the same as for AC, just a DC voltage is applied instead of AC.

Mere information HER

Varenr. 110-050-09