Description

The EML RS 242 is a replacement for the famous Telefunken RS 242. All parameters are identical, apart from heater current, which for the EML tube was chosen higher. (See also notes)

RS 242 was designed by Telefunken as a small transmitter tube for portable applications, and for amateur radio. It's good sound, made it a popular audio tube amongst Japanese collectors. The combination of gain=17, and Rp=5k, and remarkable linearity of the tube curves, allows many interesting applications. To reduce acoustic coupling from the outside air to the glass, we have chosen a short cylinder glass, because this the smallest surface. At the same time, the glass is thicker than as normal, making it more difficult for sound waves, or chassis noise, to vibrate the glass.

RS 242 has the European B4 Socket.

High Resolution

Guarantee program for first owner.

The first owner can register the tube within 4 weeks after receival, at the Emission Labs website, to participate in the 5 years guarantee program, which is additional to the legal obligations of the seller.

Our Guarantee conditions

Register here for the 5years guarantee

Features

• Gold Plated Grid (Note8)
• Soft rubber suspended tube base
• Hard metal Construction (Note1)
• Extra large getters
• Hand blown Glass bulb
• Anti-microphonic Anode- and grid suspension
• These tubes are shipped in a high quality dual box
• Tube printing with 24k gold, and red color burned into the glass
• Machined, solid tube base pins for highest contact precision. YAMAMOTO tube sockets highly recommended.
• Gold Plated, black ceramic socket

CURVES WILL BE PLACED HERE

EML RS 242. AC heated tube curves. See Note 3

CURVES WILL BE PLACED HERE

EML RS 242. DC heated tube curves. See Note 3

Curves made with Sofia Curve tracer.

S-PARAMETERS here

RS 242 Mechanical Data		Size including Socket (but excluding pins) 145 x 58 mm Weight of one tube: 140 Gram Shipment weight for pair in gift box: 350 Gram Pin 1: Anode1 Pin 2: Filament Pin3: Filament Pin4: Grid

Notes

1. Hard-metals can be used in electron tubes, though these are more difficult to use, and more costly than classic nickel. This results in less distribution of the tube parameters, and better long term stability. Wolfram grids allow the most precise grid wire distance, because wolfram is an extreme hard metal. Best grid geometry ensures uniformity and linearity of the tube curves. Gold plating of the grids has several advantages, such as increased bias stability, some protection against accidental overload, and better linearity of tube curves.
2. Heater Current of original RS242 was chosen by Telefunken company as low as they could get it, to make the batteries of portable equipment last longer. Today, this is no requirement any more, and we chose slightly higher heater current, to make the heater wires thicker, and increase lifetime by this.
3. Heater Voltage is always defined at the tubes pins itself. There may be some voltage drop along the socket contacts. So voltage measured at the tube socket wiring should ideally be 4.1V.
4. Do not experiment with lower filament voltage, to expect better lifetime. We already specify filament voltage for the best lifetime.
5. Average Plate Characteristics are made with the Sofia Digital Curve tracer. The curves with AC heating are 100% compatible with Telefunken.
6. Individual Test data, such as: Matching Data, Grid Current, Vacuum, Filament Current, etc., are on the Certificate that is on the outside of the tube box. Each tube is numbered from the inside, with a metal Tag.
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