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au-999

I just picked up an AU-999, which is loaded with flying saucers, and am also going to get ambitious.

Can anyone advise what the Digikey part number is the the 9002 transistors?

Does the ZTX795A replace both the XA495 and the 9002s?

Is there any significance to the blue dots on some of the FS's?

Some pix attached. Pretty filthy...sounds OK. I'm really interested in what it sounds like after the new transistors.

Thanks!
 

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Forgot about this thread - I have since finished that AU-999 and sent it to a gentleman in France. I got my information from people such as Echowars so you are certainly in good hands with him.

In response to your PM, I'm sorry, I use my personal web space for hosting of temporary photographs and I no longer have the amp to take pictures of.
 
Gents thanks for the response....Question...on the 495's that I eyeballed last night I see different suffix's for them...like 495 013 and 495 015 something like that; What is the significance of the suffix numbers? These are all PNP's correct?

Thanks.
 
OK...you're learnin' me...I perused the schematic and now understand how many are PNP's and NPN's. I ordered parts and will begin replacing them this weekend.

Thanks.
 
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I recapped the top side. REplace about 8 of the 495's with 795a's. So far so good. Waiting for a shipment from Digikey and Michael Percy.

This amp sounds better every time I turn it on. I do believe I will sell it when finished (because I have too many now) but this is an interesting project. Very nice to work on.

I did, however, run into a problem after woring on one of the driver boards. Suddenly, I was getting static out of the left channel...volume up or volume down. Output volume was notmal but with this annoying static. At a loss I decided to tweak the EC and bias pots on the board and when I touched one of them...static GONE! I re-flowed solder and it sounds sweet.
 
love my au-999.it's one of my star performers. i have the later issue non-flying saucer issue. it has never been serviced and doesn't need to be. it was checked and bias set. great unit, smooth highs and great bottom end.. you will enjoy!
 
Thanks. I am finally getting to resolution of the problem I created while replacing those flying saucers.

I look forward to listening to it.
 
Good news Zekeman - I've been watching this thread - so I am glad its finally moving in the right direction. :thmbsp:
 
What value Orange drop caps did you use to replace the Flying saucer transistors? I would be interested in this replacement if anyone has had success. Thanks
 
across said:
What value Orange drop caps did you use to replace the Flying saucer transistors? I would be interested in this replacement if anyone has had success. Thanks
Click to expand...

You are scaring us with that request. Look up the definition of capacitor and transistor. They are very different devices and one would never replace the other.

The "flying saucer" transistors get their name from there unusual case design. They were state of the art in 1970 but they proved to be very unreliable and that case design was quickly abandoned.

There are several excellent AU999 threads discussing modern replacements for these obsolete transistors.

- Pete
 
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