I currently own the 555a. What I love most about it is its warm, rich, natural tone. It's just so musical too. I'm wondering how the sound compares to the 777A and 999 (with the removal of filter), particularly the warmth. I seem to hear mixed reports about the 999 and its warmth, but perhaps that's before the removal of the filter.
Sansui AU-555A vs. AU-777A vs. AU-999?
- Thread starter smithyy
- Start date
stereofun
Super Member
I have all three, all restored, with the 999 being modded all the way.
Let me start with the 555a - it is indeed an extremely listenable and warm beautiful sounding amp. I could die happy with just that one.
The 777a was acquired because I loved the 555a sound so much. The 777a does everything the 555a does so well, but adds quite a bit more perceived power, even if it's only some 5 watts. It likewise has more detail and a superior stereo image - one of the best. The 777a appears to be a bit higher voiced, with some emphasis on the mid to high mid, and then again a bump at the very low frequencies. In that sense, it might not be as well rounded as the 555a, yet - imo, the 777a is the undisputed king of the cap coupled amps. Restored it is gorgeous sounding.
Now onto the 999 - it is a bit different circuit topography, more modern (...well relative to the 555/777, which are really more 60'ties design.) It features direct coupling and dual rails - where it however still has a leg in the "old camp" is that it's output stage is all same polarity output devices (like the cap coupled amps.) The 999 is a formidable amp in terms of build quality, featuring separate pre-amp and driver boards serving each channel. Beautiful symmetry ! It also has an exquisite tone control section with controls featuring individual resistors rather than cheaper variable pots (this nicety is shared with the 777a, Eight, Eight deluxe). Now by every measure this amp should sound fantastic, but it just sounds good to great. One culprit is a pre-amp that stock fails to reach it's full potential. Another weak spot is it's diffential amp, where you want even current, here the resistors a not tight tolerance and there is no current mirror or as in the contemporary Eight, an option to balance current via trim pots. Also some triple nines came with an ungodly subsonic filter build into the cirtuit, that really robs deep bass, which at the time was considered unwanted turntable rumble or low level wow and flutter.
.....So the trick is to help her along and make her sing to the high standard and ambition she was build. Once you do that - are you kidding me. You get the best of both worlds - lush analog sound but with detail and clean power that stays composed much longer than you'd imagine - add in an impressive soundstage, with great separation and presence. Do not believe the 999 cannot play fat and heavy. It can produce clean bass so low you feel you could count along the Hertz.
All these amps are keepers.
Let me start with the 555a - it is indeed an extremely listenable and warm beautiful sounding amp. I could die happy with just that one.
The 777a was acquired because I loved the 555a sound so much. The 777a does everything the 555a does so well, but adds quite a bit more perceived power, even if it's only some 5 watts. It likewise has more detail and a superior stereo image - one of the best. The 777a appears to be a bit higher voiced, with some emphasis on the mid to high mid, and then again a bump at the very low frequencies. In that sense, it might not be as well rounded as the 555a, yet - imo, the 777a is the undisputed king of the cap coupled amps. Restored it is gorgeous sounding.
Now onto the 999 - it is a bit different circuit topography, more modern (...well relative to the 555/777, which are really more 60'ties design.) It features direct coupling and dual rails - where it however still has a leg in the "old camp" is that it's output stage is all same polarity output devices (like the cap coupled amps.) The 999 is a formidable amp in terms of build quality, featuring separate pre-amp and driver boards serving each channel. Beautiful symmetry ! It also has an exquisite tone control section with controls featuring individual resistors rather than cheaper variable pots (this nicety is shared with the 777a, Eight, Eight deluxe). Now by every measure this amp should sound fantastic, but it just sounds good to great. One culprit is a pre-amp that stock fails to reach it's full potential. Another weak spot is it's diffential amp, where you want even current, here the resistors a not tight tolerance and there is no current mirror or as in the contemporary Eight, an option to balance current via trim pots. Also some triple nines came with an ungodly subsonic filter build into the cirtuit, that really robs deep bass, which at the time was considered unwanted turntable rumble or low level wow and flutter.
.....So the trick is to help her along and make her sing to the high standard and ambition she was build. Once you do that - are you kidding me. You get the best of both worlds - lush analog sound but with detail and clean power that stays composed much longer than you'd imagine - add in an impressive soundstage, with great separation and presence. Do not believe the 999 cannot play fat and heavy. It can produce clean bass so low you feel you could count along the Hertz.
All these amps are keepers.
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stereofun
Super Member
Yes, the 777a is pretty rare even in the U.S. while I haven't listened to a 777-non a- My best guess is it would be compareable to the a-version, once restored.
The best part of the 999 is how easy it is to work on and how well it's documented, including all it's mods. If you don't need gobs of power, the 555a is definitely also easy to come by - here you might consider the 505, which shares the 555a's main amp and is basically a slightly newer discount version of the 555a, with a bit more beefy power supply. It has better low end, and I actually prefer it over the 555a, not for looks, but Sonic's.
The best part of the 999 is how easy it is to work on and how well it's documented, including all it's mods. If you don't need gobs of power, the 555a is definitely also easy to come by - here you might consider the 505, which shares the 555a's main amp and is basically a slightly newer discount version of the 555a, with a bit more beefy power supply. It has better low end, and I actually prefer it over the 555a, not for looks, but Sonic's.
It's a shame they're so rare. I originally asked the question because my first choice would be a 777a, as it seems like it would be the next logical step for a 555a lover. Although the emphasis on the mid to high mid would be a concern. As it's so rarely available, I was wondering if I "settled" for the 999, how it would compare. You're certainly selling me on the 999, though!
The 555a seems to have a mid-bass accentuation, which I think is a large part of why I like it so much. Does the 999 share this trait? Apart from this, how's the treble? I'm probably younger than most on here and find myself really quite sensitive to higher frequencies.
The 555a seems to have a mid-bass accentuation, which I think is a large part of why I like it so much. Does the 999 share this trait? Apart from this, how's the treble? I'm probably younger than most on here and find myself really quite sensitive to higher frequencies.
stereofun
Super Member
Yes, you are right about the 555a mid bass voicing, giving it a warmish tone. Don't worry about the 777a mid, it has excellent tone controls so I just run the mid minus one and the rest neutral - besides the detail and presence of that mid is part of the magic, voices are really projected well. No, if you see a 777a for sale, run- don't just walk it's also a beautiful thing with it's six pack of tone controls.
The 999, when fully modded is NOT a step down, but rather a different voicing, not as warm and groovy, but with a more audiophile and clean presentation without harshness.
For instance, let's say I switch from the 999 to 777a, my first impression is wow, then I listen a bit more and I begin to pick up on it's shortcomings such as less channel separation, background noise and distortion, although very well behaved, it sounds gorgeous though. Then I switch back to the 999 that I now have decided can't quite compete with the 777a - and guess what. Another wow because of the clean power and the precision and calm of it's beautiful lush soundstage. yes......crazy I know, but that's how it is everytime I rotate.
You know one benefit of amp collection is that you can have two wife's - both beautiful, yet very different - Now we pray that she doesn't read.
The 999, when fully modded is NOT a step down, but rather a different voicing, not as warm and groovy, but with a more audiophile and clean presentation without harshness.
For instance, let's say I switch from the 999 to 777a, my first impression is wow, then I listen a bit more and I begin to pick up on it's shortcomings such as less channel separation, background noise and distortion, although very well behaved, it sounds gorgeous though. Then I switch back to the 999 that I now have decided can't quite compete with the 777a - and guess what. Another wow because of the clean power and the precision and calm of it's beautiful lush soundstage. yes......crazy I know, but that's how it is everytime I rotate.
You know one benefit of amp collection is that you can have two wife's - both beautiful, yet very different - Now we pray that she doesn't read.
Another great answer.
I think I'm going to hold out for the 777a, as it sounds like it would match my tastes better. The 999's I've seen when restored and perhaps also modded if lucky don't come cheap at over £1,000. I'm unable to perform even the simplest of work myself, unfortunately. So spending that much on something I'm not 100% keen on wouldn't be wise, as much as I would like to have both of them.
Correct me if I'm wrong, but I've also gone through a few images of different 777a's and can see voltage switches, which means I may be able to buy from anywhere in the world, hopefully making one easier to find one. Is this common with all the 777a's sold or just some of them?
I think I'm going to hold out for the 777a, as it sounds like it would match my tastes better. The 999's I've seen when restored and perhaps also modded if lucky don't come cheap at over £1,000. I'm unable to perform even the simplest of work myself, unfortunately. So spending that much on something I'm not 100% keen on wouldn't be wise, as much as I would like to have both of them.
Correct me if I'm wrong, but I've also gone through a few images of different 777a's and can see voltage switches, which means I may be able to buy from anywhere in the world, hopefully making one easier to find one. Is this common with all the 777a's sold or just some of them?
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Hipocrates
Super Member
@stereofun Tom, what speakers do you use with your Sansuis?
The Fuxtor
Addicted Member
Aside from the extras goodies the 777a has ( I like the low pass preouts) , I think I still prefer the 555a. It has a simpler refined sound that just gets everything right.... I have had both restored versions and maybe the 555a just pops more afterwards??
What about the 666 or 888?? They should be mentioned maybe?
What about the 666 or 888?? They should be mentioned maybe?
stereofun
Super Member
Wharfedale Diamond 8.4 - modified. Really an inexpensive speaker with really good woofers, so a little tweaking here and there makes them pop.
Hipocrates
Super Member
Thanks, I asked you because a trade a pair of speakers that worked great with mine grab another ones but at the end did not worked out as expected... so now I'll have to get something for them.
Cheers!
stereofun
Super Member
P.s for all you cap coupled fans - laid back speakers such as Wharfedale are not ideal for the warm and not crystalline sound of those old designs. One of the best combos I've heard - and a very inexpensive speaker with tremendous bang for the buck - is a Polk RTI A3 matched to either a 555a or a 505. The polks are forward and very detailed at the top, yet uses a clever chamber system that makes you wonder where the subwoofer is hidding. On a daily basis I listen to the 555a and the RTI A1, but helped my friend with a 505 and the bigger RTI A3 - seriously good combo.
stereofun
Super Member
The 666, 999 and 888 are very similar in layout - non of them are cap coupled, so a bit different sound more or less like a 999 with variations. I agree the 555a is voiced for a more balanced or sweeter sound than the 777a - but the level of low end power power and mid detail - here almost 3D soundstage - from the 777a is what really makes it my favorite - again rig synergy and speaker position can really make huge differences, not to mention personal preferences. They are all great amps !
smurfer77
Super Member
The 777 sonic signature is very similar to the 777A. I would go for either, but I must admit that the 777A might have fixed some issues with the 777 (I have a couple of 777 with drivers getting way too hot... and am starting to think the 777A was a fix, not just a regular update although I never saw a service bulletin for the 777).
Yes, the AU-777A is available with an 'international transformer'; I don't know if its on all of them, but it's on mine and very common. I think Stereofun has pointed out elsewhere that the 777D is likely just the japanese (100V only) version of the 777A. Not sure what happened to the 777C
That's what happened to me to. I did however, end up getting an AU-999 again and doing all of the mods and have to admit now it's very very good, as stereofun says. In fact, it sounds indistinguishable from my AU-888 now (but with those bigger power supply and stepped attenuator etc, maybe it IS actually better than the 888 (?)). Note, that they sounded the same in my home, only after applying the feedback mod, which brings the AU-999 feedback to the level of the later 666 and 888. The 666 sounds very similar to the AU-888. If you aren't going to do the 999 upgrades, the 666/888 is a much better proposition in this direction.
I prefer my 777A over almost anything (except the newer Alphas, which sound very very similar to the 777A). That said, Stereofun is 100% right that when you go between the 777A and 666/888/999 design there is another level of clarity and bass control. It's just that the 777A does everything else so right, and it's still amazing on clarity, bass quality and quantity, etc. The 777A probably shouldn't sound as good as it does. But it does. I think the fact that the newer Alphas sound so much like it, is a testament to the 777/A, or possible the AU-111/AU-70 which the 777/A are likely voiced after.
On the tone of the 777A i actually found a slightest depression in the mid, at least relative to the 666/888. Turning the mid tone control on the 888 to -1 makes it a lot harder to separate the 777 and 888 in blind tests.
The 555A is a favourite of mine, with amazing mid-bass as discussed, and it has a certain air to the highs that is really appealing (and I think somewhat missing on the 505, which might be the reason the 505 feels like it has more bass... I can never decide which way around it is). But as Stereofun right says, the 777A has a low end authority, and the 555A can not match it in this regard. The 777A has less 'air' than the 555A but I find the 777A presentation more realistic, but that might be due to the fact that many modern recordings have way to much vocal 'breath' and the 555A highlights this sometimes in a good way and sometimes it's too much. Anyway, the 555A is an amazing and common amp... a true bargain and I could happily live with it.
And Stereofun is right on another thing.... you can have more than one amp and enjoy all flavours. One is simply not enough. However, if I'm choosing one, its the 777A. Probably followed by the 888, out of those mentioned.
For more rantings check out my thread Sansui AU-777A vs all contenders but keep in mind, its just personal opinions, evolving over time with my experiences.
Yes, the AU-777A is available with an 'international transformer'; I don't know if its on all of them, but it's on mine and very common. I think Stereofun has pointed out elsewhere that the 777D is likely just the japanese (100V only) version of the 777A. Not sure what happened to the 777C
That's what happened to me to. I did however, end up getting an AU-999 again and doing all of the mods and have to admit now it's very very good, as stereofun says. In fact, it sounds indistinguishable from my AU-888 now (but with those bigger power supply and stepped attenuator etc, maybe it IS actually better than the 888 (?)). Note, that they sounded the same in my home, only after applying the feedback mod, which brings the AU-999 feedback to the level of the later 666 and 888. The 666 sounds very similar to the AU-888. If you aren't going to do the 999 upgrades, the 666/888 is a much better proposition in this direction.
I prefer my 777A over almost anything (except the newer Alphas, which sound very very similar to the 777A). That said, Stereofun is 100% right that when you go between the 777A and 666/888/999 design there is another level of clarity and bass control. It's just that the 777A does everything else so right, and it's still amazing on clarity, bass quality and quantity, etc. The 777A probably shouldn't sound as good as it does. But it does. I think the fact that the newer Alphas sound so much like it, is a testament to the 777/A, or possible the AU-111/AU-70 which the 777/A are likely voiced after.
On the tone of the 777A i actually found a slightest depression in the mid, at least relative to the 666/888. Turning the mid tone control on the 888 to -1 makes it a lot harder to separate the 777 and 888 in blind tests.
The 555A is a favourite of mine, with amazing mid-bass as discussed, and it has a certain air to the highs that is really appealing (and I think somewhat missing on the 505, which might be the reason the 505 feels like it has more bass... I can never decide which way around it is). But as Stereofun right says, the 777A has a low end authority, and the 555A can not match it in this regard. The 777A has less 'air' than the 555A but I find the 777A presentation more realistic, but that might be due to the fact that many modern recordings have way to much vocal 'breath' and the 555A highlights this sometimes in a good way and sometimes it's too much. Anyway, the 555A is an amazing and common amp... a true bargain and I could happily live with it.
And Stereofun is right on another thing.... you can have more than one amp and enjoy all flavours. One is simply not enough. However, if I'm choosing one, its the 777A. Probably followed by the 888, out of those mentioned.
For more rantings check out my thread Sansui AU-777A vs all contenders but keep in mind, its just personal opinions, evolving over time with my experiences.
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AnalogueBen
Well-Known Member
Good write up on these legendary amps, Smurfer77.
So I've got the 555a, 666 (restored) and 777a and thought I'd just add a few comments of my own. Starting with the 555a, It's an incredible little amp, I love the smooth highs and there is a lot of bass, not tight, but warm and overall one very pleasing unit.
When I got the 666 I liked the accuracy it presented, it was a bit more lively but not as smooth the the 555a. In the bass department it felt lacking and thats understandable due to being non cap coupled when comparing with the 555a/777a, plus the subsonic filter it had inside. After the recap and a few tweeks this amp is a real favorite of mine, plays all music well and has lots of detail and feels a lot stronger than stock. Also to note about the 666, it uses a full complementry output design (PNP/NPN) versus the quasi complementary on the 555a, 777a, 888 and 999. Stock vs stock I do favor the 555a tho.
The 777A is in its own league, such a realistic presentation, great separation, lots of bottom end. It has the best facia and controls of all three in my opinion, but one niggle I find is with the tone controls..I know the are not potentiometers but use resistors, however I like being able to adjust the potentiometer type just a wisker here or there to my liking, where with the 777A there is only complete steps in adjusting..no biggie really.
I have to make a start on the restoration when funds allow as it has a weak channel and so I don't use it.
Smurfer77, the restorstion of your 777A is simply a work of art, extremely good reference for other owners of this amp, and an incentive to motivate others to restore their classic Sansuis.
So I've got the 555a, 666 (restored) and 777a and thought I'd just add a few comments of my own. Starting with the 555a, It's an incredible little amp, I love the smooth highs and there is a lot of bass, not tight, but warm and overall one very pleasing unit.
When I got the 666 I liked the accuracy it presented, it was a bit more lively but not as smooth the the 555a. In the bass department it felt lacking and thats understandable due to being non cap coupled when comparing with the 555a/777a, plus the subsonic filter it had inside. After the recap and a few tweeks this amp is a real favorite of mine, plays all music well and has lots of detail and feels a lot stronger than stock. Also to note about the 666, it uses a full complementry output design (PNP/NPN) versus the quasi complementary on the 555a, 777a, 888 and 999. Stock vs stock I do favor the 555a tho.
The 777A is in its own league, such a realistic presentation, great separation, lots of bottom end. It has the best facia and controls of all three in my opinion, but one niggle I find is with the tone controls..I know the are not potentiometers but use resistors, however I like being able to adjust the potentiometer type just a wisker here or there to my liking, where with the 777A there is only complete steps in adjusting..no biggie really.
I have to make a start on the restoration when funds allow as it has a weak channel and so I don't use it.
Smurfer77, the restorstion of your 777A is simply a work of art, extremely good reference for other owners of this amp, and an incentive to motivate others to restore their classic Sansuis.
smurfer77
Super Member
Good write up on these legendary amps, Smurfer77.
So I've got the 555a, 666 (restored) and 777a and thought I'd just add a few comments of my own. Starting with the 555a, It's an incredible little amp, I love the smooth highs and there is a lot of bass, not tight, but warm and overall one very pleasing unit.
When I got the 666 I liked the accuracy it presented, it was a bit more lively but not as smooth the the 555a. In the bass department it felt lacking and thats understandable due to being non cap coupled when comparing with the 555a/777a, plus the subsonic filter it had inside. After the recap and a few tweeks this amp is a real favorite of mine, plays all music well and has lots of detail and feels a lot stronger than stock. Also to note about the 666, it uses a full complementry output design (PNP/NPN) versus the quasi complementary on the 555a, 777a, 888 and 999. Stock vs stock I do favor the 555a tho.
The 777A is in its own league, such a realistic presentation, great separation, lots of bottom end. It has the best facia and controls of all three in my opinion, but one niggle I find is with the tone controls..I know the are not potentiometers but use resistors, however I like being able to adjust the potentiometer type just a wisker here or there to my liking, where with the 777A there is only complete steps in adjusting..no biggie really.
I have to make a start on the restoration when funds allow as it has a weak channel and so I don't use it.
Smurfer77, the restorstion of your 777A is simply a work of art, extremely good reference for other owners of this amp, and an incentive to motivate others to restore their classic Sansuis.
Really spot on with a lot of those comments. I think the 666/888 can sound slightly dry or even bright, at first, going from the 555A, but after a while I feel its just accurate with a bass clarity the 555A doesn't quite match. But the 555A is really special in it's presentation, where as maybe the 666/888 are a bit more 'hifi' ?
AnalogueBen
Well-Known Member
Yep, "hifi" is a very fair call, and I guess the 555a was, and is more "tubey". All due of course to the continued advances made by Sansui to lead the audio market, which has proved it's self still after all these years
