Martin Logan Quest Z 50Hz Difficulty

[Chris Daly]

Dear DIYer's

An interesting problem to solve, it looks like Martin Logan haven't
provided for customers using their speakers in countries using 50hz
AC. Yes they provide a internal conversion to 240v but 50hz -60hz
as stated on the rear panel looks like its not actually catered for.


The said speaker turns on for 1 min then fades away its high frequencies
A study of Cockroft Walton Voltage multipliers provides info that one should
note the added ripple of a 50hz supply, with a typical solution of
adding more capacitance to the C/W array. At the moment its plug the speaker in again at 240v 50z and your back for a minute- until it fades
away again Hmmm pretty frustrating. The panels appear OK - they
wouldnt work at all I think- if they were down in conductivity.
The Quad 57 seems to work in all countries - it uses 10nf caps
in its C/W circuit

Is it just a matter of adding capacitance to reduce ripple?, has anyone
had experience with ML speakers ML PSU's and different AC supply
frequency. ML claim their circuit is proprietary - but I think have an
obligation to come clean if their speakers only work on 60hz.

Thanks / Chris

[MJ Dijkstra]

Hi
I've run the ML sequel on 50 Hz without problems.
It seems to me that the voltage multiplier is a rather simple and non criticle device.
Did you clean the panels? Could be some leakage.

[PMik]

You should contact Jim Power at ML and ask him,
he will give you the ansaw for solving your trouble
http://www.us.martinlogan.com/customer_service.html

Here you can read about what ML owners has to say regarding his service
http://67.19.167.226/~tdacquis/forum...ead.php?t=5291

[Chris Daly]

Hi
Thanks for your replies, the washing of Logans I have heard about
and I have looked up some info about how to do it.

Yes I agree ML have great service and Melodie has already
been mentioned to me as being very helpful.

I am just surprised why Quads don't need washing ?
My 57's some 48 years old still sound brand new.
yet ML only 8 years need all this maintenance.

Thanks / Chris

[moray james]

Martin Logan do not. Your Quad's would be the only ones in the world thier age that still sound like new. The process of degrigation is slow but constant.
Something that you might consider doing with your ML's would be to change the HT supply from negative to a positive one. Jim Strickland of Acoustat figured out this was a good idea and used it in his speakers. For the most part over a year the average air particulate charge is positive. That means that if your diaphragm charge is positive you end up repelling air borne particles from your diaphragm. Hope this is usefull.