Quad ESL 57 problem

[British high fidelity]

Hi guys my friend has recently bought a pair of 57s from a guy in Germany, they have been totally refurbished except the power units, and now for the issue on certain tracks wheather cd or vinyl the seems to be a quick shift in the sound from left to right as if, a balance knob was turned rapidly from left to right, this only occurs when there is a build up in the song, we have changed interconnects and also swapped out the power amp from the quad 606 to a 303 and the issue is still there, they crazy thing is at the exact same point on the cd or vinyl everytime, your views and knowledge is greatly needed please

Hifi consists of

Rega rp3
Cambridge 650p phono
Quad 606 power
Rogue audio valve pre amp
Quad ESL57s
Audiolab cd player

[Barry]

Hi guys my friend has recently bought a pair of 57s from a guy in Germany, they have been totally refurbished except the power units, and now for the issue on certain tracks wheather cd or vinyl the seems to be a quick shift in the sound from left to right as if, a balance knob was turned rapidly from left to right, this only occurs when there is a build up in the song, we have changed interconnects and also swapped out the power amp from the quad 606 to a 303 and the issue is still there, they crazy thing is at the exact same point on the cd or vinyl everytime, your views and knowledge is greatly needed please

Hifi consists of

Rega rp3
Cambridge 650p phono
Quad 606 power
Rogue audio valve pre amp
Quad ESL57s

Have you tried swapping over the speakers? Does the effect remain the same, or does it move right to left? If the latter, then the problem lies with the speaker; though I can't think for the moment what that might be.

[Ali Tait]

Clamp board?

[British high fidelity]

Clamp board?

Sorry clamp board what is that

[Barry]

Sorry clamp board what is that

They are a retro-fittable circuit fitted to the secondary side of the audio transformer, designed to prevent possible arcing and damage should the speaker be fed with a signal greater than 20V rms.

[British high fidelity]

OK can that cause this scenario

[Firebottle]

Yes but it would be a loud volume level. Does it happen when very loud?

[British high fidelity]

Well when volume is at 1o'clock so quite loud

[British high fidelity]

Also when he bought them apparently everything was replaced new except the power boxes, could this be the issue

[Ali Tait]

Does it happen when playing quietly?

As Barry said, swap the speakers to see if it pans the other way, then you know for sure it's the speakers.