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a stonecold Matrix |
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audiomik 
Old Croc 
Joined: 06 April 2010 Location: Bath, UK Status: Offline Points: 2962 |
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 Posted: 17 September 2014 at 10:59am |
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Re: "@ Audiomik I did not post to discuss any of those topics but to gain some insight as to why the Amp in question runs cold"
You will find one clear answer to this, although in brief, within my post! Things also have moved on considerably since the Hitachi Application Paper you refer to as well  Mik |
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Warning! May contain Nuts
plus springs, washers, screws, etc, etc. |
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Earplug
Old Croc
Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216 |
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Posted: 17 September 2014 at 12:34pm |
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Have you bothered checking the bias current? Does the amp have a preset for adjusting the level? Maybe it´s been set too low by some previous tinkerer. That would explain why it doesn´t sound too good (as referenced to by my previous joke - which you didn´t quite catch
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Earplugs Are For Wimps!
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SMP
Young Croc 
Joined: 16 March 2013 Location: East London Status: Offline Points: 1226 |
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Posted: 17 September 2014 at 5:23pm |
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I currently have some install work that is more pressing but will spend time on it by weekend for sure. but do not recall seeing cermet or similar when lid was off. just a value set by resistor I think all SMD yukky crap it built from as well. I will bench it proper asap post findings here
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kedwardsleisure
Old Croc
Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947 |
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Posted: 17 September 2014 at 9:43pm |
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can you post a schematic of your matrix so we can advise where the design has gone wrong?
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Kevin
North Staffordshire |
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Muckerbarnes1
Old Croc
Joined: 20 March 2010 Location: Stroud Status: Offline Points: 2654 |
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Posted: 18 September 2014 at 3:23pm |
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The answer is simple. The ambient temperature is high. In the winter it will feel nice and warm to touch. Due to humidity changes also, it may well sound 'better.'
 Or maybe not!!The only way to back up any theory of a cold AB MOSFET amp as posted is figures. Quiescent current, heatsink temp, ambient temp, and of course a screenshot of applied sine wave with parameters. Until then I'm afraid it is all in the realm of the OP's opinion. As a very old hand on Hitachi based MOSFET power amps, I have no issues with the Matrix take on this circuit. I have many of them in installations which perform very well. I have had thousands of amplifiers in my hands over the years. I have just calculated that an old installation in one cafe bar has now completed 38,000 hours of run time with 3 Matrix amps. They are in a clean area and have never been touched. They also sound very good, as expected. Whether they are hot or cold I don't care TBH. That is VFM!! Edited by Muckerbarnes1 - 18 September 2014 at 3:24pm |
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Billy Dawg.
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burningbush
Old Croc
Joined: 25 May 2009 Location: Pictland Status: Offline Points: 5897 |
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Posted: 18 September 2014 at 3:50pm |
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Alright peg leg?
 Are you up and about now? |
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music is the message
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jbl_man
Moderator Group 
Joined: 12 January 2005 Location: London. Status: Offline Points: 11155 |
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Posted: 18 September 2014 at 3:57pm |
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"Just say yes"....i just spotted that Gav.
 No foreigners here please,This is an English forum,nothing for you Scots here.  Yep,'ole peg-leg is up and about.....he de expert on old mosfet amps,we just had an old ppx with all sorts of daft combinations of numerous faults, Mr.Barnes he fix it good. |
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Be seeing you.
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burningbush
Old Croc
Joined: 25 May 2009 Location: Pictland Status: Offline Points: 5897 |
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Posted: 18 September 2014 at 4:25pm |
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Ha, been keeping out of it. Besides, some of my best friends are English....
...anyway, find out tomorrow whether I'm in Scotlandastan. Good man that Muckers, keeping another PPX in action, he da fixah. |
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music is the message
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Muckerbarnes1
Old Croc
Joined: 20 March 2010 Location: Stroud Status: Offline Points: 2654 |
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Posted: 18 September 2014 at 5:28pm |
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Ha haa. Funny. Jake the peg? I walk like Clyde the Orang Utang on sticks.
Hadrians Wall |
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Billy Dawg.
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burningbush
Old Croc
Joined: 25 May 2009 Location: Pictland Status: Offline Points: 5897 |
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Posted: 18 September 2014 at 5:48pm |
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Yeah, we'll get the community service guys on it repointing that wall. Maybe raise it up a couple of metres, don't want you lot coming over here stealing our dole money and hospital beds. Bunch of pirates.
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music is the message
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GEB
Old Croc
Joined: 13 November 2009 Location: East Midlands Status: Offline Points: 1993 |
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Posted: 19 September 2014 at 5:02pm |
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So what were the new amps you used in the end SMP?
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kedwardsleisure
Old Croc
Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947 |
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Posted: 19 September 2014 at 5:59pm |
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leak stereo 20
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Kevin
North Staffordshire |
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