QUAD ESL 57 - Help needed.

[Wakefield Turntables]

Hi everyone I hope you can help. I've been looking into updating my Quad ESL 57's. I got the service history from One Thing Audio. They were last fully serviced in June 2010. There has been some suggestion that the Bass panel might by down on output. To be brutally honest the 57's hardly get used and were bought on a whim. I originally intended moving to be a bigger house and then start using them. This never happened . So, as you all know I love to restore things and I have thought about replacing the bass and treble panels with the more efficient products from OTA, this would make an excellent project, however, I also just feel like sending them off and getting them fully overhauled. I'm at a loss to understand how the bass panels may be down on output considering they have hardly been used. Could anyone explain this phenomenon?

Thanks

A

[Light Dependant Resistor]

How do they sound to you ?

[Wakefield Turntables]

I've not fired them up for a year or so. I'm doing my research first before I make any rash decisions. That's why I'd like to understand a little about bass panel deterioration. I understand that the bass panels can lose their diaphragm coating over a period of time. Some have suggested 10-15 years. I appreciate I will get suboptimal bass output if the diaphragm is compromised or worn down. It's the deterioration process in the bass diaphragm that interests me. The speakers are stored in a warm environment and barely used, perhaps less than 50 hours, yes it's a crime, sorry!

[Firebottle]

You will get reduced bass output if the rectifier/EHT block is less than optimal.

With old ones some of the individual rectifiers would fail and the 6000V EHT would droop and the bass output reduce.
Sometimes when this happened you would get a hum on the bass panels, audible when ear right against the speaker grille.

If there is no hum detectable then your blocks are probably OK and up to scratch.
Don't forget the '57 isn't the most efficient speaker either.

[Wakefield Turntables]

Thanks Alan, OTA reply reads as follow :-


"The service we carried out at the time would’ve been : -

2 x Treble panel rebuild

2 x Eht unit

2 x Clamp board
The components in the audio transformer updated.
The bass panels were within spec at the time.
The only thing likely to have changed by now is the
Performance of the bass panels.
Given past experience they are probably well down

In output by now."

[Bencat]

As someone who uses Quad ESL57 every day and having had mine updated and restored by A Quadthing Ltd the only way to tell if any of this has happened is to put the speakers on and leave them on for five to six hours to get the panels fully charged. Then play some music through them and see how they sound . It will be obvious if the bass panels are down and you can then work from there.

Using them and playing them even if there has been a loss in the bass panels will not harm the speakers in any way they will just have a very skewed output which will be quite bass light .