Sansui AU-X11 output replacements

spaghetti

spaghetti

Active Member
I was finally able to put my hands on a Sanui AU-X11, I'm now cleaning and reviewing the amp, I am planning to keep it mostly as-is if voltages look good with the exception of the black flag caps on the power amp boards.

So, since I'm not going to overhaul it, I'd like to replace the original outputs and put them away in storage until the day comes when I'll have time to overhaul the unit. In the meantime, I'd like to use the amp at least for a while with up-to-spec TO3P replacements, as the current metallic TO3 production doesn't include any high Ft products.

The Sansui AU-X1 uses 3 pairs of 2SC2493/2SA1068 and delivers 160W RMS, the very same power delivered by the X11 but with only 2 pairs. Given that the 2SC2493 is a 100W transistor (10A) I was wondering what would be the wattage/amperage requirement for any substitutes on the X11? Should I look for ~130-150W transistors or would 2SC2837 and 2SA1186 be good enough?
 
Register to hide this ad
I was very impressed with the performance of 2SC6145A//2SA2223A that I used in a BA-F1 that I reconditioned. They are complementary and intended for audio use (of course) and are very robust. The transistor replacements you mention should be fine, there were some concerns about the value of 'Cob' on the ones I used above - but the ones you mention are probably closer to the originals. ;)

You can browse the Sanken catalogue here
https://www.semicon.sanken-ele.co.jp/ctrl/en/product/category/Transistor/#
 
Last edited:
Hyperion said:
I was very impressed with the performance of 2SC6145A//2SA2223A that I used in a BA-F1 that I reconditioned. They are complementary and intended for audio use (of course) and are very robust. The transistor replacements you mention should be fine, there were some concerns about the value of 'Cob' on the ones I used above - but the ones you mention are probably closer to the originals. ;)

You can browse the Sanken catalogue here
https://www.semicon.sanken-ele.co.jp/ctrl/en/product/category/Transistor/#
Click to expand...
I'm wondering how these outputs looked on a square wave ?? As you know I'm having issues with these outputs in a AU-X11... Curious minds....
 
The Fuxtor said:
I'm wondering how these outputs looked on a square wave ?? As you know I'm having issues with these outputs in a AU-X11... Curious minds....
Click to expand...
They were fine, I am sorry I didn't take pictures of the oscilloscope traces (oscillograms), or compare particularly with other amplifiers that I have run that test on, like the AU-X1.

Have you replaced ALL the Black Flags with C0G/NPO ceramics? - have you done ALL the stability modifications applicable to the AU-X1 on this AU-X11 - which should have them done. You know that you are having issues with the Phono inputs (and maybe Phono Mother Board?) - you should know this was the focus of much of the instability affecting the AU-X1 - and by implication the very similar design AU-X11... the modifications cure it. ;)
 
Hyperion said:
They were fine, I am sorry I didn't take pictures of the oscilloscope traces (oscillograms), or compare particularly with other amplifiers that I have run that test on, like the AU-X1.

Have you replaced ALL the Black Flags with C0G/NPO ceramics? - have you done ALL the stability modifications applicable to the AU-X1 on this AU-X11 - which should have them done. You know that you are having issues with the Phono inputs (and maybe Phono Mother Board?) - you should know this was the focus of much of the instability affecting the AU-X1 - and by implication the very similar design AU-X11... the modifications cure it. ;)
Click to expand...
All black flags are gone .... I'm still having the instability with the phono cards all pulled out, so I have to assume it's a driver card/ output issue .
 
You must log in or register to reply here.
Back
Top Bottom