Frequently Asked Questions...

Will my amplifier drive ESL’s ?

ESL’s can be difficult to drive due to the low impedance presented at high frequencies and due to the reactive nature of the load. Generally, if an amplifier is capable of nearly doubling it’s output into low impedances it will be ok. There are some exceptions to this rule such as with class A amplifiers.
If the amplifier manufacturer does not recommend loads of under 8 ohms it will probably not drive ESL’s. If the amplifier manufacturer states the amplifier will drive 4 ohm loads or lower, there is a very good chance it will be ok.


How much power do I need?

How long is a piece of string?? This depends on the size of the room you use the speakers in and the type of amplifier you use to drive them.

Typically amplifiers that are capable of delivering high current will perform best. It is better to have an amplifier rated at say 30 watts with high current capability than an amplifier rated at say 100 watts with poor current capability.

We have found the best results are gained from high current amplifiers of around 100 watts upwards.


Will I need to reinforce the bass output?

This depends upon the size of listening room and the type of music you enjoy.

ESL’s are notoriously poor at reproducing deep bass so if you enjoy heavy rock, organ music etc, reinforcement may be necessary.

Sub woofers can be integrated with ESL’s successfully as long as they have good transient response. Slow sub-woofers will sound ponderous and ½ a beat behind the panels.

The best form of bass reinforcement comes from a dipole (open baffle) design followed by motional feedback types and infinite baffle designs. However, there are some good transmission line and isobaric sub woofers available that integrate with ESL’s very well indeed.


How long does it take to build the ESL IV kit?

This will depend upon the facilities you have at your disposal. Typically our clients report that they spend between 15 and 20 hours building the panels.


Are the high voltages used to operate ESL’s dangerous?

In a word, yes. This has to be taken in context though.
The polarising voltage that is applied to the diaphragms is typically around 1.5 to 6kv. However, there is very little current involved so accidental contact with this supply will give a shock similar to receiving a shock from an elevator button after walking over nylon carpet on a dry day.

The voltage from the audio step-up transformer can be fatal.

Unless you are qualified, never touch any of the audio wires with signal playing, especially at moderate to high levels. Always switch off the speakers and unplug them from the mains before stripping them down. Allow at least 30 minutes for residual charge to dissipate.

It is not recommended for people with heart problems or wearing pacemakers etc, to conduct repairs on the high voltage sections of ESL’s.

How difficult are the Quad and B&W repair kits to use?

This depends upon your skills as a handyman and your understanding of the repair process.
Most of our clients report that they have had complete success with the repair. Others have struggled a bit but still have fixed their speakers.
We are continually improving the instructions that come with all our kits to incorporate comments by clients and to overcome difficulties they have experienced.
We do give assistance by email and telephone where necessary, to help clients resolve their problems.