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View Full Version : Sansui AU-517 and AU-719 restorations (lotsa pics!)



pete_mac
21-02-2012, 02:33
Sorry in advance for the multitude of pictures!

My father and I are Sansui nuts (over 50 units between us!) and the pride of place in my current system is taken by a restored Sansui AU-719 which has been fully recapped/restored. I also have a AU-517 which I've recapped. The 517 sounds great but the 719 takes things a bit further. It is one of the Super Fidelity models with the Diamond Differential driver boards. The improvement in clarity, accuracy and resolution vs the 517 is quite obvious to my ears.

The 719 is 90WRMS/ch vs 65WRMS/ch for my AU-517, which is not a huge difference. The physical layout is very very similar to the AU-517, but with a simpler control amp section, a more complex/sophisticated power supply board, and the Diamond Differential circuitry in the driver boards.

As you can see from the internal shots, the 719 didn't have the same build quality standard as the 517/717 wich were all black inside with internal trim/cover panels etc. The transformers are also bare with no black cladding. I do wish this amp had the same black finish as the others, and I was tempted to strip the whole amp down and paint the chassis... but a painted chassis doesn't make an amp sound any better, so I decided to leave it as-is.

The caps used throughout are Panasonic FC series, Nichicon Muse bipolar, Elna Silmic II for signal path applications, and also some small Panasonic and Epcos stacked film capacitors for the 1uf capacitors. All of the MV12 diodes (same as the VD1212) were replaced with a series pair of 1N4848 diodes, and the notiorious 'black flag' ceramic caps were replaced with silver micas. As part of the 'Stage 1' recap I retained the original PSU filter caps, so I also added 1uf 100V bypass caps across them as per the other Sansuis of this era.


http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719fronttop.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719insidetop.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719front1.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719drivers.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719powersupply.jpg

I also replaced the original binding posts with proper 5 way units which allow the use of speaker cables with banana plugs. Thankfully the 719 already has binding posts as standard, so the rear panel has circular cut-outs. This made the retrofit much easier.

I'm actually contemplating at least the top row of speaker binding posts with higher-quality solid copper binding posts, rather than gold plated brass. Not sure whether I will notice the change, but it is bugging me nonetheless. I also want to change the RCA sockets for the AUX input to solid copper sockets.

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719oldspeakerterminals1.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719speakerinside.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719newspeakerterms.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719newspeakertermsrear.jpg




A quick comparison of the build quality of the 517 vs the 719 (the 517 is far superior in this regard):

http://i535.photobucket.com/albums/ee359/petemacozfoz/AU719fronttop.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/pete_mac08.jpg


The front panels are damn similar:

http://i535.photobucket.com/albums/ee359/petemacozfoz/au719finished1.jpg


Some 719 info:

http://www.classicaudio.com/forsale/san/AU719broA.jpg


A few photos of the 719 with a few of its family:

http://i535.photobucket.com/albums/ee359/petemacozfoz/au719finishedstack2.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/au719finishedstack3.jpg


Listening comparison between 517 and 719 (with my old Dynaudios... I still miss them sometimes) :

http://i535.photobucket.com/albums/ee359/petemacozfoz/Vintageshootout5.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/Vintageshootout6.jpg

Stage 2 of the mods (completed last weekend!) involved the installation of new power supply filter caps. Epcos 15000uf 63V are very well regarded, nicely spec'd caps which should comfortably out-perform the original 32 year old caps.

They are slightly narrower but taller than the originals (35mm x 105mm vs 40mm x 80mm) so I needed to make up some spacers to suit the original 40mm capacitor clamps. Dad (skippy124) had done this in the past using some PVC pipe painted black. Insead of painting some pipe, we sourced some black spekaer ports which were 35mm internal diameter and I cut some 1/2" sections with a split to allow the spacer to slide over the capacitor. I did some test-fits in the pictures below:

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcos1.jpg


http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosspacersport.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosspacersport2.jpg


The original caps in-situ:

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosoriginalcaps.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosoriginalcapsbottom.jpg


Here is a comparison of a new Epcos capacitor vs an original Elna:

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcoscomparison.jpg[/QUOTE]

Here are the new capacitors installed with some Arcotronics 2uf polypropylene bypass caps which I had lying around. I used some ring crimp terminals and stripped off the plastic outer covering for better access and solderability.

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosandbypass.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosandbypass2.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosdone.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/epcosandbypass3.jpg


So, how does it sound after the big filter cap replacement? I might be imaging things (and it's obviously impossible to do a direct A/B comparison) but I feel that there is slightly more detail and the sound is tighter and punchier overall - and this was during a low-level listening session last night. Tomorrow I'll get the opportunity to open the taps a bit and see how it performs. The amp sounds even more refined than it previously did. Definitely no audible adverse impacts upon sound quality as a result of moving from 12000uf to 15000uf capacitors. I think this is well worth doing if you're restoring your amp and intend keeping it for many years to come.

Stage 3 will be the aforementioned binding post and RCA socket upgrade, also fitting a new power cord with Belden 19364 cable (the original stuff is twin core figure 8 cable!) and a nice Martin Kaiser mains plug. I may also rewire some of the smaller internal signal-carrying wire and larger speaker terminal wire too.

John
21-02-2012, 08:29
Lovelly work and you will be rewarded with another 20 to 30 years of life
I love old Sansui's but only have one in my system

The Grand Wazoo
21-02-2012, 08:35
Very nice job, well done.
There'll always be a soft spot in my heart for Sansui kit.

panos_adgr
21-02-2012, 09:12
Well done! Superb! I love vintage audio and audio restoration. Machines of that time had excellent sound and they are timeless. I wish you lots of ours of musical joy! Thanks for sharing!

Sansui was the Hi-end of that time.

Rare Bird
21-02-2012, 10:25
2uF bypass ! i use 4.7uF + 0.01uF Bypass for each cap that size..

pete_mac
21-02-2012, 23:23
Thanks for the comments gents!


2uF bypass ! i use 4.7uF + 0.01uF Bypass for each cap that size..

Yeah, I was contemplating something along those lines, but decided to stick with the values that Sansui used from the factory (they fitted 2.2uf bypass caps to 15000uf caps, so the 2uf is pretty close). I do have a bunch of 0.01uf caps so I can alway try these with the 2uf.

If I decide to experiment a bit, I also have a big supply of ITT PMC 2R and ITT PMT 2R 4.7uf polypropylene capacitors in a beige-coloured moulded plastic case. These could be good candidates...

Barry
21-02-2012, 23:53
Don't apologise for the photographs Pete. We love photos here on AoS, and yours are superb.

Congratulations on the refurbishment. Your hard work will pay dividends and give you many happy hours of listening pleasure.

Well done!

MartinT
22-02-2012, 07:26
Very nice refurbishment and those big Sansuis must give great pride of ownership.

Martinh
22-02-2012, 08:13
Wow, those amps are beautiful - I want one!

Martin

sq225917
22-02-2012, 09:14
When changing the values of bypass caps or attempting multiple bypasses you really should scope them out for ringing, it's all to easy to over do it. They likely sound better because the old caps will have had much higher ESR due to their age.

Wakefield Turntables
22-02-2012, 20:26
Some nice work I only wish I could drop on a pair cheap enough to refurb ;)

Martinh
22-02-2012, 20:44
What about this one? Quite tempted myself, Martin


http://www.ebay.co.uk/itm/Excellent-Sansui-AU-717-Stereo-Integrated-Amplifier-/260956173707?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item3cc233358b#ht_500wt_922

northwest
22-02-2012, 20:58
I was actually given a Sansui Tuner by a chap. I really didn't know what it was. But the second I hooked it up to my system I just knew it was something great. It is an old wood cased tuner and I have spent some time on the cosmetics and it looks good as new and sounds great.

Mothman
22-02-2012, 21:58
Nice job Pete and great photos. I just love the look of Sansui kit from that classic era, amazing build quality:thumbsup:

pete_mac
22-02-2012, 22:56
When changing the values of bypass caps or attempting multiple bypasses you really should scope them out for ringing, it's all to easy to over do it. They likely sound better because the old caps will have had much higher ESR due to their age.

Ah, I see. My father is a tech/hobbyist (with an enormous Sansui collection... we hav around 55 units between us!) and he has all of the usual diagnostic instrumentation including a 'scope.

How would I go about measuring such 'ringing'... across the terminals of the filter caps or elsewhere in the circuit?

I've also been advised that I should try a resistor in series with the by-pass cap (in the order of 1-5 ohms). It seems counter-intuative to me, but I guess it couldn't hurt to try it. I need to read up on this a bit more methinks.

pete_mac
23-02-2012, 12:44
One further tweak...

The original power cable was quite... erm... 'poxy'. Thin figure 8 twin-core as fitted as standard to US models. I decided to upgrade it using some Belden 19364 power cable with 3 x 14AWG conductors, 'belfoil' shielding and integral drain wire, and a nice (not too over-the-top) Martin Kaiser silver-plated AUS mains plug. Given the size of the cable (around 10.5mm diameter) the usual strain relief/cord grip wouldn't work, so Dad sourced me some nice Thomas and Betts heavy duty jobbies which worked perfectly. They are pretty big but you don't see the rear of the amp anyway.

Very happy with the end result, and the thin original cord is banished forever!

A HUGE thanks to David from mains-cables-r-us for his quality customer service. Highly recommended (as most of you on here already know ;) )

http://i535.photobucket.com/albums/ee359/petemacozfoz/newcable1.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/newcable2.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/newcable3.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/newcable4.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/newcable5.jpg


I also made up some cables for my DAC and DI using Martin Kaiser IECs and AUS mains plugs, some heatshrink and some carbon-look Techflex.


http://i535.photobucket.com/albums/ee359/petemacozfoz/diycable1.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/diycable2.jpg

Marco
23-02-2012, 12:47
That should've given a massive sonic improvement, Pete, as that old power lead was pretty shit!

It's areas like that in audio where significant advances have been made since the Sansui was produced :)

Marco.

pete_mac
23-02-2012, 12:52
That should've given a massive sonic improvement, Pete, as that old power lead was pretty shit!

It's areas like that in audio where significant advances have been made since the Sansui was produced :)

Marco.

Indeed Marco, first impressions are very promising. Of course, it's damn near impossible to do a A/B comparison once this kind of tweak has been undertaken, but even at low levels there is the impression that the music sounds a bit clearer and unstressed. Whatever it is, I like it!

Now to get my brother-in-law to visit (he's an electrician) and install that dedicated power line that I've been hankering for!

Marco
23-02-2012, 13:25
Nice one, Pete, and you've hard-wired the cable too, which is good!

I've always loved high-end Sansui (and Onkyo) kit, as it's generally a cut above most other Jap gear :)

Marco.

pete_mac
23-02-2012, 13:28
Nice one, Pete, and you've hard-wired the cable too, which is good!

I've always loved high-end Sansui (and Onkyo) kit, as it's generally a cut above most other Jap gear :)

Marco.

Funny you should mention that... the temptation was MIGHTY strong to remove the IEC connector from the rear of the DAC19, install a little smoked perspex blanking plate and mains cord grommet, and wire the Belden straight into the unit itself. I may yet do this as the DAC19 is knocking my socks off and I can't see myself selling it any time soon. It is easily reversible anyway.

I'm a BIG Sansui fanboy... my father and I have a collection of around 60 units between us nowadays. Some of their gear sounds pretty damn decent (AU-517, 717, 719, 819, 919, AU-D11, AUD11 II, and the later AU alpha stuff. The big dedicated preamps and power amp models obviously speak for themselves.

The Japanese market saw some quite exotic Sansui gear never destined for overseas markets. Some of it is truly high-end stuff!

Marco
23-02-2012, 13:31
If you don't intend playing around with power leads, hard-wiring is always better, as IEC sockets are nasty things, sonically - even the 'fancy' ones! ;)

Marco.

pete_mac
26-02-2013, 01:51
Even though it has been a while since I've posted on AOS, I've still been lurking in the background on a regular basis. I thought I'd post a little update re: my beloved AU-719 long-term project.

As mentioned earlier in the thread, this was a non-working unit which was brought back to life by Dad (skippy124 on various forums) after a lot of hard work and troubleshooting, including sourcing a NOS Sansui board from sansui-parts-shop.com. She has been fully recapped with Panasonic FCs, ECQVs and Elna Silmic IIs, and the power supply filter caps with Epcos screw terminal capactors. I have a few more potential tweaks here and there - possibly the installation of metal film or other fancy resistors in the preamp/signal path, and I also need to get around to fitting a pair of 22pf silver micas into the phono stage. The sound quality is very nice indeed.

Cosmetically (and I would argue functionally ;) ) I fitted CMC solid copper binding posts and a heavy duty Belden 19364 power cable and silver-plated Martin Kaiser AUS power plug. A resprayed top cover addressed the issue of the worn scratched original cover.

http://i1307.photobucket.com/albums/s587/petemacsna/719latest1_zps92c1259b.jpg

http://i1307.photobucket.com/albums/s587/petemacsna/719latest2_zpse7c91388.jpg

http://i1307.photobucket.com/albums/s587/petemacsna/719latest3_zps34f424c5.jpg


Dad also managed to secure a NOS Sansui faceplate for the 719 (and also my 517) which means they both look as-new when viewed from the front. The current faceplates are quite clean, but there are a few minor nicks on the top and the sides. You just can't beat brand new - I reckon these would most likely be the last NOS 517 and 719 face plates in the world! I will fit the new face plate in future once I stop moving the amp around so much, as I'd hate to nick it.

http://i535.photobucket.com/albums/ee359/petemacozfoz/newfaces1.jpg


The last piece of the puzzle is the base plate. The cheap non-painted silver base plate looks cheap and nasty. Dad drew up the original AU-717 base plate in a CAD program and organised for a few new base plates to be made up and had them powdercoated (or painted... I forget which) in black.

They look very nice indeed and very OEM apart from the lack of the warning sticker. Unfortunately there is a minor difference in a few screw holes vs the 717 base plate along the rear edge, but for the time being there are still six or seven screws holding the new base plate in position, so it is rock solid.

I might even look at cleaning-up the original 719 base plate some day (there is light corrosion and surface rust) and painting it black. If it turns out nicely, I will refit it (due to the extra mounting holes) and the current black base plate can be used on a future Sansui project instead.

Overall I'm ecstatic with the black base plate as it really completes the look and "de-cheapifies" the 719. The exterior of this amp is now closer to the better-built 517/717 in terms of its external appearance.

A big thanks to Dad for taking the initiative to draw up the base plate for one of his own projects, and his generosity in having a spare base plate made up for me at the same time :thmbsp: :D


http://i1307.photobucket.com/albums/s587/petemacsna/719latest4_zps2310baf5.jpg

http://i1307.photobucket.com/albums/s587/petemacsna/719latest5_zpscdc46951.jpg

http://i1307.photobucket.com/albums/s587/petemacsna/719latest6_zps3c661f2c.jpg

http://i1307.photobucket.com/albums/s587/petemacsna/719latest7_zps143d9056.jpg

http://i1307.photobucket.com/albums/s587/petemacsna/719latest8_zpsf5aff521.jpg



The amp currently taking pride of place in my system is a restored Sansui AU-X701. Whilst the front panel is a departure from the earlier amps (this is a 1987 model) the X-balanced circuit design is a class above IMHO.

She's been fully recapped with Nichicons, Panasonics and Elna Silmic IIs thoughout, as well as eight new Bourns trimpots and a pair of nice DNM slit-foil power supply filter capacitors (designed and manufactured in the UK of course). :) A heavy duty Belden 19364 power cord has also been fitted in place of the oringal figure 8 power cable.

This amp sounds brilliant!

http://i535.photobucket.com/albums/ee359/petemacozfoz/aux7012.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/slitfoil6.jpg

http://i535.photobucket.com/albums/ee359/petemacozfoz/aux701recappedmainampboard2.jpg

MartinT
26-02-2013, 07:02
Nice work, Pete. Those NOS front panels do look good.

Wakefield Turntables
26-02-2013, 11:11
Brilliant stuff.

istari_knight
26-02-2013, 16:53
:clap: Nice work, they dont make 'em like that anymore! I used to have an AU-3900 which always sounded nice.

pete_mac
27-02-2013, 23:19
Thanks for the kind words all, and I promise that I will make the time to post here more regularly. As mentioned earlier, I regularly lurk in the background as I always find valuable information and opinions on AOS, so I really should participate more often.

Ian Walker
22-03-2013, 00:24
http://www.sansui.us/Amplifiers.htm

Here's some Sansui phoowee..

Ian.

Seoolas
16-04-2018, 22:54
Hey,
I happen to be an AU-719 owner as well and I would really like it if I could see the pictures of your restoration.

snowman_al
18-04-2018, 06:16
Hi Panos, and welcome.

If you use Chrome or Firefox browsers you can now add an extension to them that will show most old 'photobucket' pictures.
Google ''photobucket hot link fix'' or ''photobucket embedded image fix'' and use the one you like best.

Seoolas
10-05-2018, 13:50
Thank you Snowman! I can now see the images...

Pete your pictures are great really! I would like to ask you about the main volume pot - mine shows signs of wear (scratchy). I managed to disassemble it and clean/lubricate it but I cannot stop thinking about replacing it if I could. Have you or anyone here got any suggestions about where to look for it?

alainrj
25-05-2018, 18:31
Those Sansui Amps look classy. Wonderful restoration job