Hissing amplifier (in Meridian M10s) help, please. - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 9th November 2011, 04:48 AM   #1
diyAudio Member
 
Join Date: Nov 2006
Default Hissing amplifier (in Meridian M10s) help, please.

Hi All,

Like all early Meridian actives I've heard (M1s, M10s, M100s etc) my M10s have begun to hiss when idle (i.e. no signal). It's not noticable when music's playing so I've lived with it but now I'm wanting to sell them on so it's time to sort it out!

The hissing is a kind of pink noise and has subtle varations of pitch, seemingly random variations. It's almost like living near the coast with either a light wind blowing or soft waves on a shingle beach... not too unpleasant.

I've been told in the past that it's probably some capacitor current leakage but I don't know which capacitors they mean!

Is it likely the power supply capacitors or caps in the amp circuits / xover circuits?

They are active speakers with 2 x 2 channel A/B amps per speaker (2 channels for bass and one each for mid/treble) with each amp board having their own power supply (1 x torroid, diode bridge, 2 roederstein smoothing caps). For those that know them, I think they are the Meridian 103 circuits.

Hissing appears to be only in the mid/treble but this could be because it's filtered out by the low pass xover section.

Does anyone have experience with a similar thing with 26+ year old amplifiers?
  Reply With Quote
Old 10th November 2011, 09:24 PM   #2
diyAudio Member
 
Join Date: Nov 2006
Any ideas to what might be causing the hiss?
  Reply With Quote
Old 10th November 2011, 10:32 PM   #3
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
ROE smoothing caps, hmm... there are some lines that have proven unreliable. Especially those with fancy plastic (?) casing, orange/red jobs, which are known to develop cracks if memory serves. In any case the suspect caps should be of the electrolytic kind. Could be coupling caps with excessive leakage (must be regular polar ones then, not the bipolar variety), could also be buffer caps with ESR gone through the roof (any hum?).

I'd try swapping the small electrolytics on one board and seeing whether that fixes it.
  Reply With Quote
Old 11th November 2011, 12:21 AM   #4
diyAudio Member
 
Join Date: Nov 2006
Hi,

Thanks for taking the time to reply - the description of the ROEs sound familiar with red end caps. Certainly the light orange/gold coloured cylindrical outer covers.

I'll have to take out the boards and have a look to see what's there on the board to replace.

Mostly showing itself in one channel/speaker so actually I can swap over the power supply (it just plugs in) to isolate that part - err, only just thought of that! That will be a good start.

When I do that I'll post up some photos.
  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
Meridian 602 Transport & Meridian 606 DAC Converter Steve M Swap Meet 10 1st October 2010 09:07 AM
Hissing DCX2496 MikeHunt79 Digital Line Level 2 27th January 2009 04:34 PM
Hissing noise from a sub DECKY999 Subwoofers 6 14th February 2008 12:48 AM
Meridian 596/24 bit dvd vs Meridian 508/bit Sclalars Digital Source 0 8th February 2006 06:48 PM
Terrible HISSING Amplifier!!! Duo Solid State 29 5th December 2002 05:00 PM


New To Site? Need Help?

All times are GMT. The time now is 10:04 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