Sansui AU-505 Recap, Restoration and Renewal

[DatGtrPlaR]

I acquired a 505 recently that I got for a great deal since one channel wasn’t sounding so great. Got home, took it apart and the 1/4” mic input from the front fell out. It was cracked in half. I had to take out the front face plate and found the headphone jack input was broken as well. Ordered some parts, Did some Deoxit cleaning, DBT test check, and all good! That was about 2 months ago. I also have a 555a that I wanted to do as well. I decided to take on both doing the 505 first with @Leestereo ‘s guidance and services. I wanted to get this done sooner, however, my shop is in the garage and it gets cold in there! I started in with the F-2001 Filter board being a little pesky booger being soldered to the chassis.



Before



After



Back in place..

DBT check!
All is well! Next is the F-1303 Tone control..

 

[archibael]

Yeah, not a fan of the filter board soldering design decision. Was my least favorite thing about opening this unit. I might be opening it back up up to add better power supply caps at some point, but I have two 2000s and a 5000x to nurse back to health first

 

[DatGtrPlaR]

I finished the F-1303 Filter and Tone Control block just recently and had problems with the left channel. This unit had to go through some deoxit cleaning initially to alleviate a left channel. I was lucky to have had a hunch that the problem reared it ugly head and was the result of a sticky tuner switch, and some further deoxit worked. I think this 505 resided previously in a smoking home. I was told by @Leestereo that testing should have narrowed the problem to whatever area it could be, which is what I should have done..which is what I need to learn more of. On to the Main Amp board….

 

[DatGtrPlaR]

Damn glue…this stuff is relentless

Cleaned..

Goin in…so far all’s well…

 

[DatGtrPlaR]

I didn’t have much time over the weekend to post… however, I finished the 505 this past Friday, and I am very pleased! The amp has a heft, big sound.. very even and musical across the spectrum. I was listening at more intervals as I recapped the main board. I saved the trimmer pots and baxandall mod last. It sounded great and the mod took it further. I measured the resistance of the old trimmers and matched the new ones before I installed them. I miss read the the bias trimmers, I had it on the DBT and the light kept glowing. I had to lower them quite a bit, as I learned the multiturn trimmers can be a bit tricky, however they are easier to dial in finely. Fired up on the DBT one more and all good! Thanks to @Leestereo and all others who helped before! I’m looking forward to start on my 555a!

 

[baeron]

I didn’t have much time over the weekend to post… however, I finished the 505 this past Friday, and I am very pleased! The amp has a heft, big sound.. very even and musical across the spectrum. I was listening at more intervals as I recapped the main board. I saved the trimmer pots and baxandall mod last. It sounded great and the mod took it further. I measured the resistance of the old trimmers and matched the new ones before I installed them. I miss read the the bias trimmers, I had it on the DBT and the light kept glowing. I had to lower them quite a bit, as I learned the multiturn trimmers can be a bit tricky, however they are easier to dial in finely. Fired up on the DBT one more and all good! Thanks to @Leestereo and all others who helped before! I’m looking forward to start on my 555a!

Job well done. It's a great Amp.
I have one all done up too.


Put some new Swamp Ash sides on too

 

[Alex22]

Well done!
It will be interesting to see a comparison between the 505 and th 555a once you have finished.

 

[DatGtrPlaR]

Job well done. It's a great Amp.
I have one all done up too.

View attachment 2518992
Put some new Swamp Ash sides on too

Nice!!!

 

[DatGtrPlaR]

Well done!
It will be interesting to see a comparison between the 505 and th 555a once you have finished.

I’m gonna have to read some hi fi magazines so I can rip off some of the descriptive language they use when I’m ready to review both!

 

[baeron]

Well done!
It will be interesting to see a comparison between the 505 and th 555a once you have finished.

I went thru a phase with restoration of the
555a
555
505
I thought I would like the 555a best. But ended up different for me.
I had it done for a friend. It has the nice wood case. He was happy with it.
Sound wise they are all close to each other.

So it came down to looks and feel.
I prefer the 505 and 555 the best.
Great features on the 555 too.

Best of luck with your next restoration!

 

[Leestereo]

Very nice restoration/upgrade! IMO, it's particularly satisfying to listen to the fruits of one's labor!