Sansui AU-717 Vs AU-7900 as integrated & power amps w/question

Discussion in 'Exclusively Sansui' started by Happytalk, Jul 18, 2017.

  1. Happytalk

    Happytalk Member

    Short story

    I've had these two amps for about 12 years. Love them both. The au-7900 was my first foray into great sounding gear. Found it while looking for the AU-717. I paired the au 7900 with vandersteen 2c's in a small room and loved it. Then found the 717 and loved that. Forgot about the 7900 until recently and man what a great piece of gear.

    Over time, after visiting friends and hearing different gear, as well as lurking a ton here. I upgraded to an audible illusions 2D recapped pre, with two bryston 2b-Lp mono blocks into late serial number 2ce's. Great budget system that is currently doing it for me and yes, I'm on a budget!.

    Short comparison.

    As integrated amps, they both have strong points. The AU-717 has a clarity and quickness that the au-7900 may be lacking, but what it lacks is made up for by a more lush, pretty sound with a very sweet midrange, and an overall warm character. Not as warm as the few marantz receivers I've heard though. I don't hear recessed highs at all, just a little smoothed over.

    The AU -717 used as an integrated amp alone is fantastic and strong. Nice neutral character with plenty of character up top. It is a little on the harsh side, but quite powerful and clear.

    I have a second system in another space with vandersteen 1c's.
    I recently acquired a NAD 1240 preamp for free and decided to connect it to the au 7900 going into the 1c's. Super bassy and slightly unnatural. While it sounds just a little unnatural, I like it. When using the NAD AU-717 as a power amp, the NAD preamp going into the AU-717 sounds more normal to me, but the 1c's in my room always sounded a little bass light. So I could just be used to it.

    A couple takeaways. 1c's can really manage and produce some bass, but likely because of some coloration in the setup.
    Overall, I prefer the preamp-power amp setup over just using either one of the Sansui's as integrated amps alone.


    Does it sound like the au 7900 needs to be recapped?

    Has anyone used either of these amps as strictly power amps?

    Was the au-7900 super bassy? It's almost like it is a different amp altogether from when it was being used as an integrated alone. Definitely a night and day difference vs the au-717. The AU-717 retains some of its character when used as a power amp. With the bassiness of the au 7900, Initially I thought it may be the NAD because they are known to have warm, thick low end, but it isn't there going through the au-717. The nad pre into the au-717 is just right. Very neutral, with some decent weight and wonderful dry clarity.

    Lastly, has anyone tried a tube pre going into the AU-717?

    Seems like the could make for a fun sound signature.

    Thanks! It's a little bit too much fun talking about this, please go easy on me...
    Last edited: Jul 18, 2017


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  2. Happytalk

    Happytalk Member

    Also. Can anyone recommend a good sub that is smaller and cheaper than the vandersteen subs that may match well with 1c's and the NAD pre - Sansui au 717 combo?
  3. LBPete

    LBPete Rolling Along Subscriber

    Long Beach, CA
    Your AU-7900 is more than 40 years old. Any amp that age would benefit from new electrolytic capacitors. You really can't judge the true sound of the amp if it still has it's original caps.

    If you can, please post the serial numbers for the database. Click on the link in my signature block.

    - Pete
  4. moefuzz

    moefuzz Active Member

    Peeyong Bangyou
    Great right up and review,

    The AU series is well loved and amongst Sansui's highest praised.


    On the bass side of things,
    Most people don't realize how much of a difference pulling your speakers out/in from the wall changes the bottom end.

    Perhaps the cabinets are too tight to the wall and therefor the speaker is not resonating (standing waves etc.)
    with the wall, room and surrounding surfaces.

    Also, You can totally effect bottom end by aiming the drivers directly out and square to the side/walls.

    A different bottom end will be found by pulling the cabinets just 6" or a foot (from current position) and slightly
    angling them center stage to your sweet spot.

    A nice rule of thumb is to set the drivers out from a corner exactly the same distance from the back wall
    as from the side wall that way the driver is resonating in a perfect triangulated corner thus reinforcing bottom end.

    I found out years ago that if my drivers were pointed (front or back) at the neighbors across the street,
    I would see flashing lights at 2 AM
    - often.

    So then I fired the woofers directly down into the floor and the resonation and sound reinforcement was roof to floor (da shits was bangin!:)) and I didn't rattle the teacups of the neighbors across or side street (too bad or too damn bad?) although the sugar cubes on my kitchen table still would have a nasty habit of reverting to ground sugar.

    But lately, I use a wedge (car audio box) which angles woofers slightly upward which helps keep resonation at the cross street -somewhat- at bay.
    Still, with moe at the wheel and Sansui on tap,
    I still see red flashing lights at 2 AM.

    Oh well,
    What more can a poor boy do?

    moe of the North

    Last edited: Jul 21, 2017
    bolero likes this.
  5. Happytalk

    Happytalk Member

    Thanks for the tips regarding bass. I have definitely moved the speakers to every possible position over time. I have a toddler so when I'm finally home alone, speakers get moved to the sweet spot. It actually corresponds closely to what you mentioned about one speaker being equidistant from both walls where the corner is.

    I've found this ideal spot after a few years of tweaking. 1c's are on sound anchor stands and spiked. Our floor is solid concrete ( under our flooring). They are not really bass light, just not the same as the 2ce's. In fact the 1c's are impressively close to where I want them to be. I've found that good sources and a particular cartridge vs another helps bring out the full range and bass control.
    I've been told that the NAD 1240 preamp going into the au7900 may be an impedence mismatch. Hence the overblown and unnatural bass presence. Any thoughts are appreciated.

    I'm also curious if a rel q 108 will have quick bass for jazz. Or a REL Tzero
    Last edited: Jul 26, 2017
  6. Happytalk

    Happytalk Member

    Here's a question. Looking for someone who has experience connecting their sansui integrated amp to a REL subwoofer. Preferably AU-717 I'm currently running a NAD 1240 preamp and using the AU-717 as the power amp. 14awg speaker wire going raw from the speaker terminals. Wondering first of all if the Sansui is a balanced output design (I doubt it) and that I can wire the speakon cable that comes with the rel to straight out of the speaker terminals. Should I get some pins with some more terminatin options instead of stuffing everything into the tiny speaker terminals?


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  7. pete_mac

    pete_mac Super Member

    Sydney, Australia
    All of the conventional topology Sansuis will work fine in this configuration.

    The AU-D11 II and all of the other X-balanced amps from that model onwards will not work. I had to sell my REL and move to a SVS sub for this very reason.
  8. rasenthiran

    rasenthiran Well-Known Member


    I have tried running REL Storm with my AU 7900/719 with no issues. As Pete advise, This REL should not be connected to the Sansui X balance amplifier. Serious damages can be done to the amplifier.
  9. Happytalk

    Happytalk Member

    Hooked up the sub. Sounding nice. But now I want the vandersteed 2wq.

    Can Anyone recommend which capacitors would be a good replacement if decide to replace them?
    Last edited: Sep 2, 2017
  10. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Hertfordshire, UK
    Yes, new thread - your post is not about comparing an AU-717 & AU-7900 as 'power' and 'pre-amps'.

    As I understand it, the rule is 'new problem' = 'new thread' (unless it is ongoing problems about the same serial number equipment). There can be exceptions to this but each must be decided on its own merit.

    Thanks for being aware of forum etiquette. ;)
    Last edited: Sep 30, 2017
  11. Hose53

    Hose53 AK Subscriber Subscriber

    Westerville, OH
    Thank you Sir!
    Yeah very impolite of me now that I reread it.
    I see there is a delete option. Should I just delete my post(s)?
    I'll start a new thread.
    Thanks again!

    Edit: Deleted my posts and creating a new thread. Thank you!
    Last edited: Oct 2, 2017


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