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AU-517 vs AU-719 - a post-recap comparison

My AU-719 serial number is:

220100329

It was originally a 220v model (label still on the back) with 3 x 2 pinned mains outlets on the back (2 unswitched and 1 switched). It has the 10,000uF 71v PSU caps. Not sure what market it was for, but I am guessing EU. The mains arrangement is exactly as drawn on the main AU-719 service schematic with the internal mains voltage selection jumper.

It had NO glue anywhere on ANY board inside and certainly no signs of ever having a recap or having glue removed. I think it left the factory with NO glue.

HTH.
 
Hi Less,

Mine the serial no is 220010008,but not sure when it was made,it can be used for 110v or 240v.There is a voltage selector behind the amp but there is NO power outlet provided so that we can connect tuner or other audio equipment.Weird cos most of the amp has it...,

Thanks,

Raj
 
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LeeS said:
These were my thoughts exactly. Replace like for like when it comes to values. The originals in my 719 were the 10,000uF 71v, so I have replaced them with 10,000uF, 80v and also moved up from 85c to 105c so hopefully that should give a little extra headroom with the voltage and the electrolyte quality, whilst retaining the original capacitance.

Like you say - If it needed more capacitance, they would have added it. One can sometimes over egg the pudding...... :nono:
Click to expand...

You are right on capacitance limits. They are a link in the power flow chain, which includes the current-voltage curves of the secondary windings, the current-voltage limits of the rectifier diodes, some chasis wiring, the current capability of the power transistors, and then the heat sink capacity of the transistor mounting planes.
 
I'll check the serial number on mine this weekend and then decode the serial numbers provided in this thread to determine if there is a relationship between year of manufacture and the dreaded glue.
 
I'm contemplating using 10000uf 80V caps in my 719 rather than the 15000uf Nichicon Gold Tunes.

The 10000uf 80v BHC Slit Foil caps that Kale mentioned below are nicely specc'd and highly regarded, and can be had for the same dollars as the Nichicon Gold Tune if purchased directly from the UK:

http://www.audiokarma.org/forums/showpost.php?p=5348944&postcount=3

As mentioned earlier, my AU-719 is the version with the 12000uf 63V caps as standard. Others have the 10000uf 71V caps as standard. The rest of the power supply is identical and the different versions of 719 have the same rated power output etc. I'd imagine that going from 12000uf original caps to the 10000uf BHC caps would certainly not be a backwards step, particularly if Sansui used 10000uf caps in many of the 719s to being with!

The only downside is that the BHCs are 35mm x 80mm, so I'd need to sleeve the caps so they fit nicely in the 40mm diameter capacitor clamps. Easily done!

Any thoughts gents?
 
pete_mac said:
...<snip>...The 10000uf 80v BHC Slit Foil caps that Kale mentioned below are nicely specc'd and highly regarded, and can be had for the same dollars as the Nichicon Gold Tune if purchased directly from the UK...<snip>...

The only downside is that the BHCs are 35mm x 80mm, so I'd need to sleeve the caps so they fit nicely in the 40mm diameter capacitor clamps. Easily done!

Any thoughts gents?
Click to expand...

Those capacitors are r-e-a-l-l-y good so I understand, (the slots in the foil help prevent eddy current build up) - so, especially as you are in the market for replacement caps - I would go for it :thmbsp:
 
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Cheers John. I PM'd EchoWars earlier today and he also suggested that they'd be a very good option in the AU-719.

Looks like this is the option I will be taking!
 
Still haven't had chance to fit my Mundorfs yet. I will get them in sometime this year..... It's hard to strip her out of the rack to do it, she is sounding so sweet, but I want to change those big caps and also some of the smaller diodes and double-diodes..... One day soon.....
 
pete_mac said:
Cheers John. I PM'd EchoWars earlier today and he also suggested that they'd be a very good option in the AU-719.

Looks like this is the option I will be taking!
Click to expand...

Correction to the above... after some difficulties sourcing the slit foils at reasonable prices, I've instead gone down the Epcos road and have sourced some very nice (15000uf 63V flavour) screw-terminal caps. They have very good specs and are well regarded. If all goes to plan these will be installed over the coming weekend. I'll post some info regarding what was needed to fit them, as they are a tad narrower than the originals (35mm x 105mm vs 40mm x 100mm orginal). I have a very neat solution to address this.
 
Woo hoo... the Epcos 15000uf 63V caps are in!

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:

epcos1.jpg


epcosspacersport.jpg


epcosspacersport2.jpg



The original caps in-situ:

epcosoriginalcaps.jpg


epcosoriginalcapsbottom.jpg



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

epcoscomparison.jpg



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.

epcosandbypass.jpg


epcosandbypass2.jpg


epcosdone.jpg


epcosandbypass3.jpg



So, how does it sound? 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.
 
Nice result Pete, they certainly look like they were meant to be there. The speaker port material looks to have worked out better than PVC pipe (no painting required).

Looking forward to having a listen!!
 
I bet the sound really sweetens up (smoother, more detail and better balance) after 60 to 80 hrs of play time. Very nice looking workmanship.

Scott T.
 
That's a very nicely done upgrade Pete, thoughtfully executed and finished. :yes:

Certainly looks busier under there with all those terminals :D

Always interesting to hear listening impressions after such an upgrade :yes:

:thmbsp:
 
scottrt said:
I bet the sound really sweetens up (smoother, more detail and better balance) after 60 to 80 hrs of play time. Very nice looking workmanship.

Scott T.
Click to expand...

Thanks Scott. She's sounding beautiful right now as-is, so if there are any further improvements I'll be as happy in a pig in you-know-what! :)

Hyperion said:
That's a very nicely done upgrade Pete, thoughtfully executed and finished. :yes:

Certainly looks busier under there with all those terminals :D

Always interesting to hear listening impressions after such an upgrade :yes:

:thmbsp:
Click to expand...

Thank you squire!

I'm looking forward to banishing the little figure 8 power cable in the coming weeks and fitting the Belden 19364!
 
A quick update. Gee she sounds nice! I had a good friend over on the weekend for a listen and he was suitably impressed.

Next round of mods will most likely include the fitment of some solid copper RCA sockets for the AUX inputs, and replacement of the top row of speaker binding posts for solid copper (rather than brass) binding posts. I may also look at some internal wiring upgrades some day. These tweaks would be the icing on the cake though... she is sounding brilliant as-is.

I'll also be taking the AU-719 to a friend's place in the coming weeks for some comparisons against some highly-fancied modern amplifiers (both solid-state and valve) to see how it compares. He runs the www.digitalaudioreview.net.au website and often has a few amps for review at any one time, so it will be interesting to hear how the 30+ year old Sansui stacks up. Looking foward to this in a BIG way!
 
Good work Pete, looks very tidy.........You have done a really nice job there...:thmbsp:

Yes, keen to hear how the Sansui wipes the floor with the contenders in the amp shootout.......
 
The final tweak for the time being (yes, I say that now... but I bet I'll be under the hood again soon).

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!


newcable1.jpg


newcable2.jpg


newcable3.jpg


newcable4.jpg


newcable5.jpg
 
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