Quad ESL989 service manual

[Solstistel]

Any ideas where I can get a service manual for the Quad ESL989

Many thanks,

Solstistel

[405man]

I asked Quad and they said they were not available, I got an email explaining why and if I can find it I shall post it later

Stuart

[JohnW]

If you cannot find the 989 service manual, then 98% of the information is in the ESL63 service manual. From an electrical perspective the 989 is basically a later 63 with a couple of extra Bass Panels. The major difference is the use of arrays of Zener diode voltage clamp on the secondary side of the 989 for overdrive protection.

Sitting behind me I have 63, 989’s and 2905’s

I can try and help if you have any unique 989 issue....

John

[405man]

John, how much difference is there between the ESL63 and the 2805, do you have any photos of what is inside the 2805, The later 63s were also fitted with the zener clamp boards and I retrofitted mine with kits from Quad about 15 years ago, I may have the sheet somewhere

Stuart

[JohnW]

Stuart,

The main differences are in the rigidity of the design, the later 2805 are very sold – this makes a big difference to LF performance.

The ESL panels themselves are 100% the same – the electronics are basically the same (circuit wise), so if you have the later Secondary side Zener clamp in your 63’s, then you don’t have to feel your missing anything.

What your 63’s really need is a much stronger frame / stable support – this is where the later 2805’s really shine...

The PCB layout in the 2805's is different from your 63's - but basically the same circuit.

I've also seen primary and secondary side Zener clamp circuits - the later 2805's have the zener clamps on the secondary side (via a whole string of diodes) - where it should be!!

John

[405man]

yes the zener clamp on my 63 is on the secondary side. I hope to rebuild my 63s with 6 panels as in the 2905 and am going to use a welded steel box section frame.

Stuart

[JohnW]

Stuart,

Well if you’re going to build your own frame - why stop at adding an extra 2 panels - why not 4.... or more

A couple of concerns would be the extra loading on the transformers - and the effects of the extra loading on the Delayline... but you can always "Carefully" play with this - once the speaker has been constructed.

However I would be concerned about the conductive frame... but this is stating the obvious... (I believe Quad's frame is also conductive - extruded aluminium).

John

[Solstistel]

JohnW,

I have downloaded a copy of the ESL63 manual, and as you say the electronics are very similar. However, I think I may have a problem with a panel and don't know how to take the grille/dust cover off. Any ideas?

Many thanks,

Solstistel

[JohnW]

Solstistel,

FIRST disconnected all leads and allow the speaker to "Discharge" over night.

Stand in front of your speaker - and carefully push / Slide to the >>>>Right >>>> the "Top / Cover / Lid / Top Hat (what ever you wish to call it)". Once this is moved about an inch to the right, it can then be lifted off.

Once the top is removed, the "Body Sock" can then be lifted off the industrial "Velcro" type attachment and rolled down the speaker.

Then you can see the screws to remove the Metal grill. Once you have done this, you need to remove the real "Dust covers" with there frames from the speakers - Front and Rear.

John

[Solstistel]

JohnW,

Thankyou, its so easy when you know how!

Many thanks,

Solstistel