The Mighty AU-X1

Just enter the values - using the SM values we have 8 x 10,000µF & 69V (there is extra capacitance in the system of ~880µF x2 @ 69V but I'll ignore that).

Which leads to:-

Charge Q = 5.52 Coulombs

Energy E = 190.44 Joules

Is that what you wanted ? :)
 
Just enter the values - using the SM values we have 8 x 10,000µF & 69V (there is extra capacitance in the system of ~880µF x2 @ 69V but I'll ignore that).

Which leads to:-

Charge Q = 5.52 Coulombs

Energy E = 190.44 Joules

Is that what you wanted ? :)

Yes, this is definitely on the right track. So when we look at joules, should we only take into account the energy reserves of the amp section or of other boards that the amp section needs to work?
 
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It depends what you are looking for - I simply calculated the energy reserves of the Main PSU capacitors ignoring any other capacitance which could arguably be counted for the Main Amp energy reserves. (like for example the 4 x 220µF capacitors on each driver board).

Not a very meaningful calculation if you expand it to the whole amplifier, don't you think?
 
It depends what you are looking for - I simply calculated the energy reserves of the Main PSU capacitors ignoring any other capacitance which could arguably be counted for the Main Amp energy reserves. (like for example the 4 x 220µF capacitors on each driver board).

Not a very meaningful calculation if you expand it to the whole amplifier, don't you think?

Yes, I agree. It shouldn't be expanded. By any measure I think 190 Joules is very good. I have to take a look to see how Audio Research calculates it, they claim 900 Joules for their new Ref 160M amp. I want to understand that number.

Back to the X1 what would the joules be for the pre-amp? I want to be sure I'm understanding this correctly.
 
Well, no pre-amp as such in the AU-X1 - so if we take the Flat Amp as the pre-amp this will be 4 x 100µF & 47.5V

Which leads to:-

Charge Q = 19 milli-Coulombs
Energy E = 451.25 milli-Joules

If we calculate for the MM Head Amp 4 x 330µF & 47.5V this gives

Charge Q = 62.7 milli-Coulombs
Energy E = 1.49 Joules

A grand total of 81.7 milli Coulombs & 1.94 Joules for the pre amp stages. (excluding the MC Head Amp as only MM OR MC can be active).

Recalculating after adding the driver board capacitance to the total for the Main PSU capacitors gives :-

Charge Q = 5.641 Coulombs
Energy E = 194.63 Joules

And a grand total of:-

Charge Q = 5.7227 Coulombs

Energy E = 196.57 Joules

What all this means I'm not sure - we know the AU-X1 sounds great :rockon::music:

:)
 
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Well, no pre-amp as such in the AU-X1 - so if we take the Flat Amp as the pre-amp this will be 4 x 100µF & 47.5V

Which leads to:-

Charge Q = 19 milli-Coulombs
Energy E = 451.25 milli-Joules

If we calculate for the MM Head Amp 4 x 330µF & 47.5V this gives

Charge Q = 62.7 milli-Coulombs
Energy E = 1.49 Joules

A grand total of 81.7 milli Coulombs & 1.94 Joules for the pre amp stages. (excluding the MC Head Amp as only MM OR MC can be active).

Recalculating after adding the driver board capacitance to the total for the Main PSU capacitors gives :-

Charge Q = 5.641 Coulombs
Energy E = 194.63 Joules

And a grand total of:-

Charge Q = 5.7227 Coulombs

Energy E = 196.57 Joules

What all this means I'm not sure - we know the AU-X1 sounds great :rockon::music:

:)

Great stuff, but shouldn't we include the filter caps (I believe 2 x 2200µF x 100V - not sure the of the rail voltage) for the EI core transformer which the brochure says are for the phono stages and the flat amp (pre-amp)?

Also, where can I read the 69V rail for the main filter caps (and EI filters) on the schematic?

file:///Users/family/Downloads/Sansui-AUX-1-Service-Manual.pdf

Thanks in advance. Sorry for the questions but I like expanding my understanding.
 
Ah right - yes that's an Alps I think, pretty much the best generally available pot, certainly back then. They can show their age (oxidisation) and are difficult to service (push nuts!) as it likely wasn't expected that they would be still in use this many years down the line. :)

Just to add on i believe the Alps pot(Big Volume Knob) is from their Black Beauty series, and are still highly sought after by many enthusiasts. The series should be from RK40.
 
but shouldn't we include the filter caps (I believe 2 x 2200µF x 100V - not sure the of the rail voltage)
Yes we should :) - another 8800µF & 68V :-

Charge Q = 598.4 milli-Coulombs
Energy E = 20.346 Joules

Grand total now

Charge Q = 6.3211 Coulombs

Energy E = 216.916 Joules

Also, where can I read the 69V rail for the main filter caps (and EI filters) on the schematic?
Using the coordinate system that Sansui uses you can see the voltage mentioned in square F4 & 5 (i.e. bottom right - F-2781) of the full page schematic (on page 14) of the SM.
 
Yes we should :) - another 8800µF & 68V :-

Charge Q = 598.4 milli-Coulombs
Energy E = 20.346 Joules

Grand total now

Charge Q = 6.3211 Coulombs

Energy E = 216.916 Joules

Using the coordinate system that Sansui uses you can see the voltage mentioned in square F4 & 5 (i.e. bottom right - F-2781) of the full page schematic (on page 14) of the SM.

Thanks for confirming and doing all the calculations as well as pointing me to the right place for the rail voltage on the schematic.

Very helpful as usual!

Just to add on i believe the Alps pot(Big Volume Knob) is from their Black Beauty series, and are still highly sought after by many enthusiasts. The series should be from RK40.

Wow, I did a little research and it does seem that the Alps Black Beauty is a "fabled" pot. Thanks for the info!

Just another thing that makes the X1 a truly exceptional unit. The more I dig into this unit, the more I find to like.
 
I need to stop reading about X1's and I need to stop working on my customers one as every time I plug it in and listen to it, I want one......they are an extraordinary amplifier rivalling the best there is to offer today!!
 
I need to stop reading about X1's and I need to stop working on my customers one as every time I plug it in and listen to it, I want one......they are an extraordinary amplifier rivalling the best there is to offer today!!
Yep!

I have to say it is brutally revealing. Some recordings I thought sounded OK before with other amps sound terrible with this amp. But good recordings.....geez!

Its pretty amazing for sure, I think the main things about the sound for me is that it is hugely authoritative with my big KEFs, plus (like I mentioned above) pretty much everything you play thru it makes it seem like you were previously listening to that music as an mp3 file (or something). And you only hear the full details on the track once you play it on the X1.

Do people feel the same way about the 919 I wonder, is this the "high speed" transistor thing in action?
 
Yep!

I have to say it is brutally revealing. Some recordings I thought sounded OK before with other amps sound terrible with this amp. But good recordings.....geez!

Its pretty amazing for sure, I think the main things about the sound for me is that it is hugely authoritative with my big KEFs, plus (like I mentioned above) pretty much everything you play thru it makes it seem like you were previously listening to that music as an mp3 file (or something). And you only hear the full details on the track once you play it on the X1.

Do people feel the same way about the 919 I wonder, is this the "high speed" transistor thing in action?
Not necessarily just the high speed amp, but other components of the design like the Current Mirror circuit in the front end of the driver circuit, the direct coupled design, so less distortion, less phase shift....there's a lot of reasons they sound the way they do.
The G22000 is pretty much the same, it has pretty much all of those design attributes too.
 
Update- the X1 has a new playmate.

I wasn't intentionally looking to match brands but as fate would have it I came across a Sansui unit locally that had always piqued my interest in the past. So I bought it, hooked it up to the X1 and all I can say is...WOW. I might start a separate thread just for this unit because I'm really impressed. Either way, it still belongs here (at least initially) because it highlights one of the strengths of the AU-X1

While I get some pictures together can anybody guess what it is ??

Here's a hint, it's probably not the first piece you're thinking of...
 
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That's right, it's an SR-838!

Visually, this has always been one of my favorite tables from any manufacturer. Such a stunning and simple design. Fit, finish and design are superb and timeless. All controls are very ergonomic. I love the cue lever in that location. The arm looks like a hi-end precision instrument. This turntable is a work of industrial art. IMO, the 838 has stood the test of time very well. The high quality black lacquer finish is also beautiful and goes very well with my modern B&W's (805D2, CM6 & CM5) which all sport the same finish. Once again, Sansui seems to have been ahead of it's time.

I had been eyeballing a VPI Prime Scout but since I'm more into digital formats I was holding off on that expense until I get the DAC I'm looking at. Maybe I have something for raised brushed aluminum platters.

This 838 came from the personal collection of a previous Hi-Fi store owner. The individual selling it included a NOS Pickering XSV 3000 with the D3000 stylus (box and all). The headshell on it was a Sansui brand but the seller did not have the original silver headshell, he said this one was on the 838 so he assumed it came with the unit. I will have to keep an eye out for one to see if it makes a difference. This purchase was meant to be because I love the XSV cartridge. I've had experience with it before and I can say it's phenomenal. I assumed the alignment wasn't set up quite right because I wasn't getting the correct imaging on my main set-up (805D2). I was a bit worried that the left MM card on the X1 phono stage had an issue because the center stage was a bit off to the right so I thought the left phono output was weaker. My brother-in law came over to help me align the cart. He brought over his Shure scale to get the tracking weight perfect and his Mobile Fidelity Sound Lab Geo-Disc to get the alignment right. We adjusted the VTA which was also slightly off. Sure enough, the adjustments made a huge difference. I played a few of the records where I had clearly been hearing the imaging issue and now it was spot on!

Does the 838 do justice to the X1's beast of a phono stage? Absolutely! So how does it sound? Well, the first thing I can say is that it is dead quiet. It also definitely has superb detail resolution and an airy, open presentation. The best way I can describe it is like what you listen to a high end speaker (or headphone) and notice the subtitles, clarity, separation, note definition and decay in the music that you never noticed on a lesser speaker. The soundstage also blew me away, I didn't know vinyl could do that. I assume what I'm hearing is a combination of the brand new XSV3000 cart/D3000 stylus, the 838 alignment being set-up properly and the superb phono stage on this X1. You know you have a magic combination when you just want to keep listening...


One last point, as you can see the table is in superb condition. The only thing I noticed when I went to check it out is that at 45rpm it would hunt slightly when set to quartz lock (33 rpm was perfect). That wasn't a deal killer for me since I don't even think I own any 45's. Regardless, when I got it home I searched the vast knowledge banks here on AK and found the simple solution in this thread:

http://audiokarma.org/forums/index....sue-with-sr-838-turntable-worse-on-45.624282/

Thanks @LBPete for the solution and @Blue Shadow for the helpful picture. It worked like a charm! 45 rpm is now spot on with or without Quartz lock. Both speeds are rock solid.












 
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Nicely played. The 838 is a top shelf TT for sure. I almost pulled the trigger on one a while back but an unbeatable deal on an SR-929 came up concurrently, so I went with that instead. That said, I'd not mind owning both, but that'll have to wait considering current valuations.

It certainly does go well aesthetically with the X-1 or really any black Sansui amp from that general era, and in terms of technical spec is quite well matched to the X1.
 
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