I need advice.


Background: I am a devoted music listener for over 50 years.  Most of my knowledge of technology is from the 70's.  
Objective: The best sound quality I can get from my system.
I have numerous amps, turntables and speakers.  The best of these is as follows:
My audio system;  Thorens TD 160 with Stanton 680EEE cartridge, Sansui AU 717, JBL L112
The Sansui (as far as I can tell) is untouched as far as any refurb is concerned. The overall quality of the audio as far as I can tell is good.  But it is what I listen to every day so I have no source for comparison. I have read that an amp that is 30+ years old is due for refurbishment (new caps, etc.).  I have been quoted $350 - 400 for a total refurbishment of the Sansui 717.  I would consider having this work done if it would make a noticeable improvement in the audio quality.  What  can I expect from such an investment?  I welcome any suggestions.
garywest
Gary,as far as I know, replacing caps can make a difference. The price quoted for the work is very reasonable, but I would inquire as what replacement caps are being used. You'll want make sure they are equivalent in quality to what came in the amp, or better.

Can you open the unit up? If you can inspect the caps, if there is any swelling, leaking, or discoloration, they'll need replacing.

Hopefully, someone with greater knowledge on the subject will chime in.

Best of luck,
Dan  
Cap failures, can cause other components to fail.

30 years is a good, long life, without failure.

Your Sansui is living on borrowed time!

I would get the caps replaced, if you like the Sansui, or want to sell it.
Yeah, either sell the Sansui to some one who wants it, or re-cap it for reliability's sake alone.

A bad failure can cascade, even blowing speakers. :)

What about digital? In additin to high rez downloads there are awesome internet stations out there you are not listening to. :) There are a bunch of internet ready receivers out there.

Best,

Erik
If the Sansui is sentimental,  I'd recap it... All electrolytic would need to be replaced, not just the power supply filter caps.... All of todays caps should be an upgrade over the old caps that Sansui used and overall its sound quality should improve a bit... If its not sentimental,  I'd dump it... Something like an Audio Refinement Complete would smoke it.  
If the Sansui's like an old friend that you can't bear to part with, by all means update it.  The improvements will be more to extend it's lifespan rather than quality, MHO...
For the same or slightly more $, you could update to something new(er), if you want to tread into the Bluetooth/WiFi/surround this n'that/whatever catches your fancy....since you're at a crossroads of sort....

Lots of shiny new toys out there....here...wherever...*G*

Don't do anything.  Keep it exactly like it is.  Recapping will increase the long term reliability, but it won't really better the sound quality.  If the Sansui is functioning properly, no buzzes, static etc., then why spend money on it.  Realistically, if the Sansui worked well for the past 38 years, then it probably will work well for another few years.

Btw, the 717 and the JBLs are a classic combo.  Love the Stanton.  Very cool.
Thanks Hwy 61!  
I'm not going to fix what ain't broke. It IS a classic combo.   I just wanted to be sure I wasn't missing anything. BTW is the recapping all about the power amp or the pre-amp or both.  Just wondering, because I have a Carver M-0.5t I could hook it up to.  What do you think?
The 70s gear is nostalgic (been through this hobby’s evolution from 1971 onward....) and that’s where the sentimental bias floats through.

the cold hard facts are that this old era gear cannot compete with the current era offerings.

I would strongly suggest that you personally audition/test-drive something current before you commit more repairs cashola to the old stuff..... the differences in performance improvements are not subtle.

This exists without prejudice to the fact that that old gear ... especially the Sansui .... has a questionable and minimal FMV thst is highly likely less than what you will fork out now, and it’s only a question of "when" the next round/stage of repairs arises.
I still have my TU-717 tuner, but it's on a shelf, so I have not listened to it in quite some time. I used to own the AU-717 as well. About a year ago, I got stuck without a modern preamp, because I replaced my integrated amp with power amps and could only insert my Boulder L3AE line stage as a temporary solution. The Boulder is only 26 years young as compared to your Sansui of 40 years. Wow, the Boulder sounded good, but after I had a cap explode in my old and untouched Heathkit amp a while back, I decided to replace the caps in my Boulder. After some break-in, the Boulder sounds fantastic and I have no urge to go shopping right now.
Kenny
In addition to electrolytic caps, Tweeter damping fluid or ferrofluid is the other thing that will go with time and use (dries out). Foam surrounds can wear out too. After more than 30 years your electrolytic caps are likely shot or at least out of tolerance - those in the signal path are most critical.

I'd be wary of simply assuming a $350 recap will get you back to original 70's performance. You should try to test your individual components separately A vs B against modern gear.  These age related failures should be fairly obvious - night and day differences. If you find your speakers need a refurb too then the cost/benefit may steer you towards a different solution.
The AU-717 is very capable, but it comes with a laundry list of problems that need to be addressed. I have worked on several of them myself, and they have what is dubbed the "Glue Syndrome". Just google Sansui Glue, and you will see it posted about allot. This stuff eats component leads when it becomes corrosive and even conductive.

The other big issue with the 717  is the filter capacitors are always bad and leaking or starting to leak.

If you can get it completely restored for $350, you better jump on that deal, because I wouldn't do what I do to them for that. I remove all the glue, and replace all offended components. More to it than that, but the glue issue must be dealt with.
Garywest ...

I love that turntable .. very musical. 

You're a music lover first and not an equipment geek. Keep the Sansui as a spare and go with tubes.  It doesn't have to be really expensive. Check out the modified Dyna 70's. Maybe a modified Dyna Pas pre-amp as well. 

Find out how to contact "Grover."  He builds excellent Dyna 70's.  A friend has one and its pretty amazing. I don't have his contact number, but someone here may chime in. 

OP
The 717 was a great product for its time. If i was on a budget I would recap using really good caps, Jensen, Mundorf or something equivalent.  If you are open to spending some $$$, there are some fantastic newer products in integrated. Before i purchased my current separates, i was very happy with a BAT vk 3000se. There are some other fine choices available for less. 
electrolytic capacitors are notorious for failure - they are made with a paste that is mildly corrosive - at some point manfs. started putting buffering agents in them - not sure when but it was AFTER the mid-1980s

Besides that, they must be conditioned for proper function; they will lose that if not used for some time

they are likely to have been used in both power amp and pre-amp 

some types of caps can lose capacitance just from aging - I don't recall which types and don't know if they were used in your equipment, but electrolytics definitely change in C as the electrolyte evaporates

I suppose changing out capacitors after some years needs to be considered standard maintenance, like changing the brake fluid on a car.

** the above is all standard electronics engineering practice and NOT subjective tweeker fru-fru **

So...
I suggest listening to some equipment from nad, Cambridge Audio, Rotel or similar well-engineered products that can be returned in 30 days or so if you do not like them.

Select some revealing program material - female vocal, snare drums, deep bass, piano, etc. and try to set up both A/B switching on short 1 minute or 30 s. segments as well as extended periods of listening.