The 19S555 Grid Choke (without center taps) is a versatile component designed for grounding the control grid in vacuum tube amplifiers. With a nominal inductance of 600 Henry at 100 Hz (0 mA DC) and a DC resistance of 6k, this choke stands out for its ability to maintain a stable grid voltage while providing a wide bandwidth. Its designation as a “Grid Choke” highlights its function of anchoring the grid to ground, offering a maximum inductive value of 600 Henry. It is compatible with a wide range of tubes, and its application method is illustrated in the image below.

In short, this choke has a much lower DC resistance (6k) than typical grid leak resistors used in tube circuits, which usually range between 100k–220k or even 1 Megaohm. This feature ensures excellent grid bias stability, preventing instability or electrostatic charge build-up in tubes, especially in worn ones or those with imperfect vacuum.

At the same time, its extremely high inductive value of 600 H provides an almost impenetrable barrier to any AC signal appearing on the grid. The signal therefore reaches the grid unimpeded, driving the tube while behaving as a very high impedance load for the previous stage. As a result, the preceding stage is relieved from providing current, achieving a purely voltage-driven operation.

It should be noted that despite its evident benefits, the implementation of this solution requires careful mechanical placement. Due to its nature, the choke is sensitive to stray magnetic flux from power transformers. Therefore, it must be positioned at a suitable distance from such components to avoid unwanted hum pickup.

The photographs are representative of the product, although slight variations in paint finish, wire color, or bobbin appearance may occur. Transparent varnish versions are also available. However, the general appearance and main features remain consistent with what is shown in the images. All items listed are subject to quantity discounts. By purchasing chokes together with other products such as output transformers, power transformers, or any other items available on the website, you can benefit from significant savings compared to the single-unit price, as indicated in the proportional discount structure below.

Model 19S555
	Universal grid choke – 600 H @ 100 Hz (0 mA DC), DCR 6k, no center tap
	Dimensions (mm) L 50 H 43 S 40 F 60 F2 *

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Dimension diagram