afroaudio
Active Member
Hi gang
Been silent for a long while but have recently found some time to start the resto of my AU-717. Cant believe its taken me almost 3 years to get to! I have been reading through everything I can find on this site and feel pretty confident diving in thanks to the brilliantly documented threads here. I am following LeeStereos blueprint so far to the letter as well as some tips gleaned from Skippy124 and others..
My unit is an earlyish model (July '77) I received the amp with the power chord cut off but all insides original if dirty. In my haste after purchasing the amp in this state 3 years back, I immediately pulled out the 2721 and 2722 main amp modules and ordered parts etc... then life got busy! Of course I should have done some testing to see where I was at before disassembling anything.
My plan is now to complete these 2 boards and reinstall and then perform the tests with dim bulb
Quick questions for the experienced Sansui techs here:
* Are the green mylar caps in the 717 worth upgrading to Polyprops at all? Even just in some key positions?
* Are the KCK ceramic caps worth replacing wholesale with COG on the main amp boards or elsewhere or are they not critical?
* Are the original output devices worth holding onto (mine test good) or would anything be gained from dropping in OnSemi subs given the choice? looking at longevity here but also hope to keep the sonic signature intact.
*Lastly, I have opted to replace the 2SA750 and 2SC1400 with KSA992/KSC1845 as advised I believe by Skippy124. Are there any other of the small signal transistors that are advisable to replace?
Thanks again to those who have gone before me and provided so much great info here, an invaluable resource and dont know where I would be without it!
cheers,
Jonathan
Been silent for a long while but have recently found some time to start the resto of my AU-717. Cant believe its taken me almost 3 years to get to! I have been reading through everything I can find on this site and feel pretty confident diving in thanks to the brilliantly documented threads here. I am following LeeStereos blueprint so far to the letter as well as some tips gleaned from Skippy124 and others..
My unit is an earlyish model (July '77) I received the amp with the power chord cut off but all insides original if dirty. In my haste after purchasing the amp in this state 3 years back, I immediately pulled out the 2721 and 2722 main amp modules and ordered parts etc... then life got busy! Of course I should have done some testing to see where I was at before disassembling anything.
My plan is now to complete these 2 boards and reinstall and then perform the tests with dim bulb
Quick questions for the experienced Sansui techs here:
* Are the green mylar caps in the 717 worth upgrading to Polyprops at all? Even just in some key positions?
* Are the KCK ceramic caps worth replacing wholesale with COG on the main amp boards or elsewhere or are they not critical?
* Are the original output devices worth holding onto (mine test good) or would anything be gained from dropping in OnSemi subs given the choice? looking at longevity here but also hope to keep the sonic signature intact.
*Lastly, I have opted to replace the 2SA750 and 2SC1400 with KSA992/KSC1845 as advised I believe by Skippy124. Are there any other of the small signal transistors that are advisable to replace?
Thanks again to those who have gone before me and provided so much great info here, an invaluable resource and dont know where I would be without it!
cheers,
Jonathan