E90F Pentode
€2.50
Delivery time: ca. 1 - 5 days
High-gm studio quality pentode
Used in driver and line stage circuits
Noval B9A; Uf 6.3V, If 0.3A; gm~10mA/V
E90F / 7693 SQ pentode for audio preamps and drivers
The E90F is a rugged special-quality pentode developed for professional wideband amplifiers. Its controlled characteristics, modest heater demand and compact B7G construction make it attractive for custom preamplifier, line-level and driver circuits.
The E90F corresponds to the 7693 and is electrically close to the 6BH6. BTB also offers a matched/balanced selection for stereo, differential and other dual-channel designs.
Suitable applications
- Tube preamplifiers and line-level gain stages
- Driver stages for following valve systems
- Studio, measurement and laboratory equipment
- Stereo or differential circuits using selected valves
Technical specifications
- Valve type
- Special-quality sharp-cutoff pentode
- Equivalent designation
- 7693; electrically close to the 6BH6
- Base
- Miniature B7G, 7-pin
- Heater
- 6.3 V at 150 mA
- Typical operating point
- Va 250 V, Vg2 150 V, Rk 100 Ω, Ia 7.4 mA and Ig2 2.9 mA
- Transconductance
- 4.6 mA/V
- Internal resistance
- Approximately 1.3 MΩ
- Maximum anode voltage
- 330 V
- Maximum anode dissipation
- 2.6 W
- Dimensions
- Maximum diameter 19 mm and maximum overall height 54 mm
B7G connections – bottom view
- Pin 1
- Control grid g1
- Pin 2
- Cathode
- Pins 3 and 4
- Heater
- Pin 5
- Anode
- Pin 6
- Screen grid g2
- Pin 7
- Suppressor grid g3 and internal shield
Audio design notes
The E90F benefits from short signal paths, effective supply decoupling and a grid stopper mounted close to the socket. Gain, distortion and output impedance depend on the operating point, load and feedback arrangement.
Safety notice: Valve circuits may contain lethal anode voltages and should only be constructed and tested by suitably skilled users.
Questions about selection and audio use
Is the E90F suitable for a high-quality audio preamplifier?
Yes, its SQ construction, 7.4 mA reference anode current and 4.6 mA/V transconductance provide a useful basis for custom line and preamplifier stages. The screen supply, anode load and operating point should be selected for the intended gain.
Can the E90F be used as an audio driver valve?
Yes, a correctly designed pentode or triode-like circuit can use the E90F to drive a following valve stage. A suitable buffer or transformer is still required when the connected load has a low impedance.
Is the E90F an attractive alternative to the 7693 or 6BH6?
Yes, the 7693 is a corresponding designation for the E90F. The 6BH6 has very similar basic electrical characteristics, while the E90F was specified as a professional special-quality type. The pinout and circuit conditions should always be verified.
Note: All brand names mentioned, such as Marshall, Fender, etc., are registered trademarks of their respective owners and are used here for descriptive and compatibility purposes only.
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The EU Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (2011/65/EU = "RoHS 2") aims to exclude certain hazardous substances from electrical and electronic equipment or to restrict the use of certain substances in electrical and electronic equipment. These include substances such as lead, mercury, cadmium, and chromium, as well as certain brominated flame retardants and plasticizers. These substances may only be used in electrical and electronic equipment up to a maximum concentration limit, unless exemptions in the annexes to the directive permit their use under certain conditions. This can reduce and eliminate harmful substances and improve the recycling of waste electrical and electronic equipment. To find out whether the component you purchased from us is permitted in your device, please refer to the current directive or the current law applicable to your country. If you are a manufacturer, please feel free to contact us to find out whether the component you require can be tested and approved according to the current directives. We would be happy to assist you.
Fact sheet on EU Directive 2011/65/EURestriction of the use of hazardous substances in electrical and electronic equipment (PDF, not accessible, 2 MB)
Source: IHK Mittelfranken
Tariff Number: 85408100900
Country of Origin: DE