Quad ESL 55/57 power supply (EHT)

ESL Labs Quad ESL 55 / 57 high voltage power supply

New EHT power supply for the Quad ESL 57

After a couple of decades the high voltage power supply is often in need of repairs. Most of them can be refurbished, but we are taking it one step further.

An improved power supply

We have developed a new power supply board that is a drop in replacement for the existing power supply. This power supply contains a health monitor circuit for each of the two bass panels and for the treble panel. This monitors the leakage current in the form of a flashing neon indicator. A healthy panel under normal conditions will show a indicator blink rate of only once every 10 seconds or less. When a panel has developed a leak the blink rate will go up or even light up the neon continuously. A leaky panel can not charge to normal levels and will pull down the power supply voltage and cause damage in the long term.
Under conditions of extremely high humidity, healthy panels can also start to leak high voltage. This is normal. In that case the monitor tells you it's probably better to power down the speaker temporarily.

High quality

The power supply is build from the finest quality circuit board. Parts have been selected for low switching noise and long life. Each panel has it's own hookup terminal and has an over current protection. The finished supply is protected from dirt and moisture by a conformal coating.

Delivery

The power supply boards are in stock and will be delivered finished and tested including mounting hardware. Please note that this concerns the power supply board only. The power supply unit with transformer is not included.