4CX250R — Eimac ceramic-metal power grid tubes (representative image)
Representative image of this product family. Image: Microwave Power Products (Eimac, formerly CPI) (MPP products overview page).

RF Power Grid Tubes · Tetrodes

4CX250R Glass-Metal Tetrode

Available on request Eimac / CPI 4CX250R

Glass-metal beam tetrode with 250 W plate dissipation, functionally equivalent to the 4CX250B with glass/metal envelope.

Plate Dissipation
250 W
Max Frequency
110 MHz
Max Plate Voltage
3.5 kV
Max Plate Current
175 mA
Worldwide shipping Cross-reference support Grunius BV · Groningen, NL

About the 4CX250R

The 4CX250R is a power tetrode manufactured by Eimac / CPI. Glass-metal beam tetrode with 250 W plate dissipation, functionally equivalent to the 4CX250B with glass/metal envelope.

Key ratings of the 4CX250R include tube type Beam Tetrode, plate dissipation 250 W, max plate voltage 3.5 kV, max plate current 175 mA, screen voltage 300 V and transconductance 25 mA/V.

Typical applications are HF linear amplifiers, SSB transmitters, scientific RF systems and amateur radio. Notable features: glass-metal envelope, equivalent electrical parameters to 4CX250B, cost-effective alternative and long service life.

Power tetrodes add a screen grid to the triode structure, giving higher gain and lower drive power. They are widely used in FM and TV broadcast transmitters, HF communications, plasma heating and accelerator RF systems, usually together with vacuum capacitors in the output network.

PartnerTubes supplies the 4CX250R worldwide from Groningen, the Netherlands — availability, lead time and price are confirmed per enquiry. Our team can help with equivalent and cross-reference types, sockets and accessories, and supply programmes for OEM and maintenance customers. Interchangeability must always be confirmed for the specific equipment.

Technical specifications

Tube TypeBeam Tetrode
Plate Dissipation250 W
Max Plate Voltage3.5 kV
Max Plate Current175 mA
Screen Voltage300 V
Transconductance25 mA/V
Max Frequency110 MHz
Filament Voltage6.0 V
Filament Current2.5 A
EnvelopeGlass-metal

Specifications are indicative and based on published manufacturer data. Always verify against the official datasheet and confirm suitability for your application before ordering.

Applications & features

Used in

  • HF linear amplifiers
  • SSB transmitters
  • Scientific RF systems
  • Amateur radio

Key features

  • Glass-metal envelope
  • Equivalent electrical parameters to 4CX250B
  • Cost-effective alternative
  • Long service life

Frequently asked questions

What is the 4CX250R?

The 4CX250R is a power tetrode manufactured by Eimac / CPI. Glass-metal beam tetrode with 250 W plate dissipation, functionally equivalent to the 4CX250B with glass/metal envelope.

What are the specifications of the 4CX250R?

Tube Type: Beam Tetrode; Plate Dissipation: 250 W; Max Plate Voltage: 3.5 kV; Max Plate Current: 175 mA; Screen Voltage: 300 V; Transconductance: 25 mA/V; Max Frequency: 110 MHz; Filament Voltage: 6.0 V; Filament Current: 2.5 A; Envelope: Glass-metal.

What is the 4CX250R used for?

The 4CX250R is used in HF linear amplifiers, SSB transmitters, scientific RF systems and amateur radio.

What are alternatives or related parts to the 4CX250R?

Related and comparable parts include 4CX250B, 4-125A, 4CX350A, 4CX1000A, 4CX3000A and 4CX10000D. Contact PartnerTubes to confirm interchangeability for your equipment.

Where can I buy the 4CX250R?

The 4CX250R is available from PartnerTubes (Grunius BV, Groningen, Netherlands) with worldwide shipping. Availability and lead time are confirmed on request. Request a quote at https://www.partnertubes.com/contact/?part=4CX250R or email info@partnertubes.com.