MARTIN LOGAN CLS schematics - Page 3 - diyAudio
Go Back   Home > Forums > Loudspeakers > Planars & Exotics

Planars & Exotics ESL's, planars, and alternative technologies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 8th September 2013, 06:45 PM   #21
diyAudio Member
 
Join Date: Apr 2004
Location: far away
Hi all,
once again, my ML CLS is finally working, but i will like to know
1- what should be the HV, i measured 1370 Vdc
2- one speaker is sounding weaker then the other, taking in consideration the age about 27 years what should be replace? the capas from the input filter, resistors, high voltage components, ect?
cheers,
Williams
__________________
williams audio
  Reply With Quote
Old 8th September 2013, 09:24 PM   #22
tyu is offline tyu  United States
diyAudio Member
 
Join Date: Jul 2009
tyu...posted

An for the bias V........i was told buy Mr Jim Powers.... who worket at ML........ at one time CLS were at 4,5k........but then ML rolled them there panels down to 3.6k......an thats were thay are today..........
John65b may have put more bias on his re-worket CLS panels an thay worket fine.........right john??


jhon65...posted
I ran Acoustat Interfaces on my used CLS II panels and sound was very good - higher bias (~5kv) and better transformers than the CLS II I/F. Much better SPL and bass too.

My original CLS panels are being re-mylared...a project that keeps getting pushed back.

I think ML reduced bias for reliability reasons. I do not know if my higher bias would shorten life of my panels.


............As for the caps an res.......yes thay can be upgreaded...but get the bias UP!
...have fun...good luck
  Reply With Quote
Old 9th September 2013, 12:21 PM   #23
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
Yes, I think the CLSII bias was reduced to 3.5kv from 5kv. I am using over 5kv now with Acoustat interface, but they are in storage.

Check bias on both interfaces to see if the same. If bias is the same (and 3.5kv), you can rule out bias and look to step up transformers, stator leaks, bad bias charge ring, coating...

You Are you using a high voltage voltmeter?

Are your panels starting to separate? Mine were separating real bad. As you know, the when the stators start to separate, they lose spl as the stators are further apart...
__________________
All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us? Life of Brian
  Reply With Quote
Old 18th September 2013, 09:09 PM   #24
diyAudio Member
 
Join Date: Apr 2004
Location: far away
Hi all,
thanks a lot for the advices!
it is correct the HV bias is about 3.8kv, i had to make a voltage divider to test it.
now it works fine,,,,,, it is detailed, but sounds a bit too strident.
do you think is worth to try changing or tuning the equ. filter?
Cheers,
Williams.
__________________
williams audio
  Reply With Quote
Old 19th September 2013, 12:55 PM   #25
tyu is offline tyu  United States
diyAudio Member
 
Join Date: Jul 2009
Thanks for your findings...................let us know your thinking as you move on with the setup....................
i setup a bias that i can set....4k-7k............if to much bias.......... it can make the sound strident..................might pull back..............like 3k-3.3k......i know you got what 15m ohms.....are more at the end of the diode string........... right befor the panels?

good luck
  Reply With Quote
Old 19th September 2013, 05:22 PM   #26
diyAudio Member
 
Join Date: Apr 2004
Location: far away
hi all,
yes are 2 resistors of 15 mega ohms, i think are in serial connection
i think that increasing this resistance will reduce the current and the high voltage applied to panels.
how it will affect the HV bias the sound, from your experience?
is any smart to readjust the input filter?

cheers,
williams
__________________
williams audio
  Reply With Quote
Old 22nd September 2013, 10:31 PM   #27
X83 is offline X83  United States
diyAudio Member
 
Join Date: Sep 2013
Quote:
Originally Posted by Williams Audio View Post
hi all,
yes are 2 resistors of 15 mega ohms, i think are in serial connection
i think that increasing this resistance will reduce the current and the high voltage applied to panels.
how it will affect the HV bias the sound, from your experience?
is any smart to readjust the input filter?

cheers,
williams
Don't omit the resistors at the end of the output of the supply! It is there for three reasons. First, it insures that you can't get enough current out of the power supply to hurt you. Second, it helps force the speaker to operate in the "constant charge" mode. Third, it helps minimize damage to the speaker in the event the diaphragm comes into contact with one of the stator panels.

If you need to calculate the voltage & current output, just use an ohms law calculator: Ohm's Law Calculator

I just ordered a few Vishay VR68 1W 10kV metal film resistors in various M-ohm values to experiment with my Monolith-III speakers which have four 15M-ohm 1/4W resistor in series.
  Reply With Quote
Old 23rd September 2013, 12:13 PM   #28
john65b is offline john65b  United States
diyAudio Member
 
john65b's Avatar
 
Join Date: Jan 2005
Location: Chicago
Just put another cap/diode in the chain. It will add another 750v.

Whoops - the power tranny secondary on the Acoustat interface is 750v - I don't remember what it is out of the CLS interface...whatever that secondary voltage is, adding another diode/cap will raise Bias voltage by that much.

If I remember correctly, there are places already on the PCB that you can add another diode and cap. The diodes in that power supply PCBs were 1N4007 (doubled up?)
__________________
All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us? Life of Brian
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Martin Logan CLS membrane re-do audioquestM-40 Planars & Exotics 36 31st January 2014 06:24 PM
Martin Logan CLS - Frame Dimensions john65b Planars & Exotics 9 5th April 2013 11:43 AM
martin logan cls Williams Audio Planars & Exotics 1 4th October 2012 09:38 PM
Martin Logan CLS panels - new Mylar trondareo Planars & Exotics 1 11th October 2009 05:34 PM
Martin Logan CLS Panel Refurb GlidingDutchman Planars & Exotics 0 10th March 2008 02:26 PM


New To Site? Need Help?

All times are GMT. The time now is 04:07 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2