Calling All "Vintage" Integrated/Receiver Owners
Oct 4, 2013 at 10:28 PM Post #10,006 of 19,143
   
thanks
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Great summary! You got to the dirt unlike many a Friday nite writes! Where some seek comfort, additional thought-food-drink and... you simply got in there and got it done!
 
Oct 4, 2013 at 11:12 PM Post #10,008 of 19,143
You're most welcome. I'm so starving for music right now, if y'all were waiting on my summary, there'd be concerned about my absence.
 
"Silent One! What kinda hokey operation are runnin' in that room?!!!" 
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Oct 5, 2013 at 4:45 AM Post #10,011 of 19,143
And finally the au-9500...



 

Looks amazing
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. It just oozes class! Enjoyed reading that thorough summary too. Shame about the bit hiss, I've been doing a bit of research on this recently, because sometimes no amount of cleaning that eradicate it.
 
For anyone wanting to understand further, this below is worth a read. It tries to explain why audio circuits make noise (the hiss). Most of it went over my head though.. 
 
http://sound.westhost.com/noise.htm
 
Oct 5, 2013 at 7:55 AM Post #10,012 of 19,143
I've had success in eradicating hiss in several Sansuis of this era via selective or comprehensive replacement of small signal transistors in the preamp, along with any known troublesome transistors in throughout the amp. You can often achieve an inky black background. It really only makes sense to do this when you are undertaking a full recap and restoration though.
 
Oct 5, 2013 at 10:17 AM Post #10,014 of 19,143
So, if I read between the lines - sounds like the 500c is better sounding overall than the 9500?
 
Oct 5, 2013 at 11:01 AM Post #10,015 of 19,143
Yeah, the 500c is one of the best amps I've listened to period. The only thing I wish it had was a more euphoric character. But then, that would also take away from it's neutrality. But a little color isn't always bad.
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Oct 5, 2013 at 11:08 AM Post #10,016 of 19,143
I always thought the 9500 looked a little bland and boring from all of the pics I've seen. But in person, it's looks waaay better. Even the knobs are solid milled aluminum(similar to my ka-907) And though it's hard to tell from the pics, the faceplate and knobs are actually a really dark purple(matches my he-6). So the looks have really been growing on me.
 
I still prefer the looks of the au-9900/11000/20000(epecially the 20000). But the appearance of the au9500 is quiet elegant and very different though. The fit and finish is impeccable as well. 
 
Oct 5, 2013 at 11:22 AM Post #10,017 of 19,143
  Yeah, the 500c is one of the best amps I've listened to period. The only thing I wish it had was a more euphoric character. But then, that would also take away from it's neutrality. But a little color isn't always bad.
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Can't afford it right now - but the 500c is the one receiver I definitely want to get.  I just keep hearing so much good about its sonic character.
 
Oct 5, 2013 at 11:36 AM Post #10,018 of 19,143
I really got lucky on mine. I scored a completely restored one for about the same price a parts/repair unit goes for on ebay. And got it right off the headfi forsale forum. The seller was in the process of moving and didn't have room for it. I was shocked there wasn't a lot of interest when I got it. He had two of them along with a restored 400 as well.
 
Oct 5, 2013 at 11:45 AM Post #10,019 of 19,143
I began to get interested in the 500c when I inherited my father in laws 50 year old Fisher Console.  The sound that comes out of this unit is quite amazing.  Even more so now since I have re-tubed it.
 
Oct 5, 2013 at 1:48 PM Post #10,020 of 19,143
  Looks amazing
tongue_smile.gif
. It just oozes class! Enjoyed reading that thorough summary too. Shame about the bit hiss, I've been doing a bit of research on this recently, because sometimes no amount of cleaning that eradicate it.
 
For anyone wanting to understand further, this below is worth a read. It tries to explain why audio circuits make noise (the hiss). Most of it went over my head though.. 
 
http://sound.westhost.com/noise.htm

 
Great article! Short version for the less technically inclined -
Signal to noise ratio is the important number with noise.
Preamps have the most effect on total noise.
Very good opamps and transistors exist that can cut noise way down - for a price.
Really cheap resistors in the preamp circuit will have an effect on noise. Really high quality resistors can cut out noise in that circuit by 3-10 dB
Discrete op-amps (transistor pairs) in parallel can cut noise down even further than integrated ones, by up to almost 10dB if well executed.
A lot of people try to goose spec'd noise down as low as possible through vague reporting in the specs.
Rules of thumb - On digital systems, you should add 10 dB to the stated S/N ratio to get analogue equivalent.
 - When only input noise is specified (i.e. -120 dB), you must add amp gain (about 40 for 100 watt amps) to get S/N (in that case, -80 dB)
 - If the amp gives a "noise figure" with awkward units, it is possible to convert to dB, but you probably won't like how bad the figure is. and don't forget to add those other effects
 - Rebuilding/restoring vintage units with tight tolerance, high quality components can make them even better
 

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