Long term ML owner - looking for maintenance advice

[jandswalker]

Hello, everyone. My name is John Walker, I live in Portland, Dorset in the United Kingdom, and have owned a pair of Martin Logan Quest Z speakers since 1999. I would appreciate advice on keeping these wonderful speakers in use, and in tip-top condition.

My power amps are protection-free, and a problem has begun to develop with the amp that drives one of the panels. I think I've found the main problem elsewhere in the system (an intermittent connection in a cable), but in taking the system apart, I've realised that the speakers are not performing as brilliantly as they did when new(er). Sensitivity overall, and treble brilliance have definitely decayed as evidenced when I plugged in a pair of cheap bookshelf speakers.

Portland is famous for stone, so it's a very dusty environment. I've already taken the panels off and carefully run the shower over them as recommended by at least one post. Are there any resources/members that would help me identify common problems with the crossover/HT unit? All the caps and other passives look like new, and I cannot see any dry joints. DC resistance between the speaker terminals was 8.3/8.4 ohm (bass unit) and 4 kOhm on the HF terminals with the panel disconnected. Resistance between diaphragm and each stator measured open circuit on my meter.

Any advice or tips on how to proceed would be very welcome.

 

[jandswalker]

They looked dry this morning, and the panels still measured open circuit - so I put them back together and tried them. They are significantly more sensitive than before their wash, and the balance sounds better too. All for the cost of less than 0.5m of Velcro tape. Thanks to the original poster who documented the breakdown and wash process so thoroughly.

 

[Rich]

Just understand that they may be on their last legs. They are now thirteen years old and panels will fail at some point, often within fifteen years. You may want to secure some replacement panels before ML decides to not produce them anymore, or raises the prices beyond what is reasonable (actually, they have done that already, but it could always get much worse in the next few years).

 

[jandswalker]

Rich
thanks for the advice - my Quests are nearer 20 years old, so they are definitely beyond their reasonable life expectation. One important result is that I've found an explanation for repeated power amp failures.
I've had Roger Sanders's book on self-build electrostatics for a while... perhaps it's time to stop procrastinating, and buy some mylar. I can remember hearing a pair of CLSes in the late '80s. Does anyone know of any self-build project that has succeeded in emulating the CLS family?

The UK distributor, Absolute Sounds, told me that they could supply replacement Quest panels, but that they would cost £1200 (about USD1800). That's still a viable option, as is buying some second-hand Quads. Scanning posts, it seems as if prices for panels is going up. Is there a reason that anyone can point to?

 

[Rich]

Scanning posts, it seems as if prices for panels is going up. Is there a reason that anyone can point to?

ML recently doubled and, in some cases, tripled the price they charge for replacement panels, with no advance notice and little in the way of reasonable explanation for the jump in prices.