▼ Menu

Inside the QQE03-20

Extras ▼


The QQE03-20, QQV03-20, QQV03-20A, QQV06-40, QQV06-40A and QQV07-50 are all European VHF double beam tetrodes based on the European pattern of a central core and two anodes suspended from the top of the envelope.

Julian Iredale has supplied this Dutch valve with a clean break across the top of the envelope and we just had to look inside.

The nickel anode plates are coated for better heat radiating. Unlike most valves the coating is on the inner working face as well as the exterior surfaces.

The electron flow is clearly concentrated on a small area as can be seen from the discolouration on the inner surface of the anode.

The central column has the beam plate to catch secondary electrons emitted by bombardment of the anode, the common screen grid as well as the heater and cathode plus the aligned control grids - one per side..

The control grid wires are gold plated. The cathode covers a considerable area.

The mechanism of mounting the two control grids is not seen.

Looking down onto the top mica sheets the heater can be seen as two hairpins. These can be connected in series or in parallel.

The cathode tube has the same curve as the anodes.

Here the two inner grids can be seen clearly.

The four supports of the control grids are seen either side of the cathode. The small rods on top of the grids are the neutralising capacitors.

No details for

Another view of the screen grid passing outside of the control grid supports.

Use browser back button to return.