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#61
11-03-2009, 04:10 PM
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Just a follow up to my AU-20000 woes. Mike aka PunkerX went through my amp, did a great job, and it now runs MUCH cooler ALL day long. Now is where I need some advice. It seems with the new caps I have lost most of the dynamics that I love so much about these amps. Do the caps need a run in time? It sounds very compressed and missing a good portion of the details, space, and soundstage it used to have. Do I put the amp in the basement with a blanket over connected speakers and just let it run? I know Mike let it run for several days and it has been going constant since I got it back yesterday. I am fairly sure the difference is in the Pre-amp section as I have several of these AU/CA/BA series Sansui's. When I audition the AU-20000 using ONLY the preamp section(separated) then hook up my non-restored CA-2000 to the same components and passages of music the difference is dramatic veiled/ not detailed with the AU-20000. I am a musician and recording engineer and rely heavily upon my ears enough to know that there is something amiss. Mike used Muse and or Simac II caps in the audio path but seemed uncertain whether these were the best choices. Any suggestions, help, advice are appreciated.... I'm hoping it's a cap run in time thing as I love this amp but if not then Mike is willing to make cap changes if that is what is needed here.... very cool guy BTW who does great work.
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#62
11-03-2009, 05:24 PM
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Electrolytic capacitors may require a couple of minutes (not days) to reform if they haven´t been used in a long time. Other types don´t need any time at all; they should perform O.K. from the very beginning.
Stupid question: have you checked nominal values and/or solder joints. I´ve soldered the wrong capacitor many times (blame my eyes).
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#63
11-03-2009, 07:06 PM
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These are brand new caps that were installed. Here is a list of repairs from the invoice if this helps.....
Recap Driver Board and Change trim pot to 15 turn Bourn's Recap Voltage regulator board Recap Power Supply and protection board Conditioned Relays Test Driver and Output transistors for Beta and Leakage Trouble shoot "Tone" Board, replaced 2 bad and 6 suspect transistors Recap Pre-amp section Recapped Preamp, Headphone, meter, phono and tone circuits Used Muse and or Simac II caps in audio path. Set DC Offset - Bias and calibrated Meters N/C 210 Watts per channel both channels driven.
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#64
11-05-2009, 08:06 PM
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It may be fixed now, you may have been hearing pleasant distortion caused by the issues above which have now been fixed.
__________________
DD:SX-1250,GX-270D-SS,Sony TC-K850ES,Onkyo DX-C206,Numark TT,GFA-555ii,HTPC,DEQ2496,RSIIIa HT:Onkyo TX-SR805,ZA SR71,DIYMA12,HTPC OOS:SX-1010, SX-1050, GX-270D-SS(#2), GX-280D-SS, GX-255,Technics SL-1800, Nak CD-6,INF QLS5,RS4001, Beta20, Seas LOKI
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#65
11-06-2009, 12:50 PM
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Stranger things have happened for sure but I'll be damned if this thing isn't starting to open up and sound better now after several days.... but mids are still a little bit compressed. Think I will reserve final sonic judgement for a while longer.
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#66
11-06-2009, 03:26 PM
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I have experienced this twice now - and I was a real sceptic before - I find it quite astonishing - keep listening...
Enjoy 
__________________
John I’ve got two legs from my hips to the ground And when I move them they walk around And when I lift 'em they climb the stairs And when I shave ‘em they ain’t got hairs
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