Quad ESL 57 Treble Panel

ESL Labs Quad ESL 55/57 refurbished treble panel.

The Quad ESL 55/57 Treble Panel

The Treble unit reproduces the mid and high frequencies. It is located in the center of the speaker, flanked by a bass panel on each side. The treble panel is sectioned into three vertical strips of which only the center strip reproduces the highest frequencies. In effect the Quad ESL 57 is a three-way speaker.

Arced treble panel

A nightmare for all Quad owners: the arced treble panel. Why does this happen and is there something we can do about it?

When Quad introduced the Quad ESL they specified a 15 Watt amplifier. Today amplifiers of over 100 Watt are perfectly normal. And the Quads can sound really good with more powerful amplifiers! The down side is that with certain musical content or accidental high volume can have disastrous effects.

Quad ESL clamp board

The clamp board protects your Quad from blowing up. Without a clamp board high voltage peaks from the amplifier can cause the treble panel to arc. This starts with a small spark but can end in quite spectacular fireworks. When that happens the treble panel may be lost for ever. A clamp board will prevent this from happening and is a lot cheaper than new panels! It only comes into effect when needed and does not change the sound in any way.

Quad treble panel refurbishment

A refurbished treble panel not only sounds like new but also looks like new. Refurbished stators, new diaphragm, new dust covers and wiring. In short a panel that will serve you well for a long time.