Information taken off AK and other places.
Hope this helps.
1979 1979-81 AU-719 (international) (USA: April 79-December 80) $575. This amp was an updated AU-717 (DC circuit or maybe with the DD/DC circuit, I'm not sure). This amp was an updated version of the AU-717 using some of the older technology of the AU-717. It’s a step down to the AU-717 and not like the AU-919 at all. It's a newer version of the AU-717 using the older technology of the AU-717. It’s 90wpc into 8 ohms. Frequency response rated to 400,000Hz with a ±170v/µs slew rate. Said to be a more audiophile type sound. This amplifier is a tad bit of a step down in actual build quality than the AU-717. AU-719 was cheaper constructed than the AU-717 but still an excellent sounding amplifier: Cheaper shielded transformers, no pre-out/main in, no anodizing on the heat sinks, thin galvanized non painted chassis, etc., etc.
From another person: From what I've read the 719 is different than the 717 using some older technology but being about 2 years or so newer in release. It's interesting that some mention their 719s having the black box transformers. I wonder if the black covered transformers are older versions or are the copper clad transformers a newer "revision" and an updated version and possibly a replacement that was done to better the sound or a cost cutting measure?
From another person: "Improved, slightly better sounding version of the popular AU-717. Completely independent power supply for each channel. Diamond Differential DC circuit for lower distortion. The DD/DC circuit is also said to make it less necessary to adjust and tune up the amp over the years to maintain peak performance. DC bias. Spring mounts for speaker wires used on the AU-717 were replaced with improved and more modern binding posts on the AU-719. Extended bass without that artificial boom, a deep and clear midrange and nice resolution in the treble. The AU-719 does not have any pre-out capability, as on the AU-717. This amplifier is 90wpc like the 819) and is clearly an updated AU-717 using the (DD/DC circuit). The AU-719 with the DD/DC circuit is clearly an updated AU-717. The 719 is 90wpc like the 819.
More 717 / 719 / 819 / 929 information
the 719 has pre-amp outs...which the 717 does have.
True, only the 819 and 919 have the pre-amp outs.
So there were two 90wpc amps (AU-719 and AU-819) in the line at the same time in place of the venerable 717. The 719 added and subtracted a few features in relation to the 717 but shared the same basic architecture.
The 819 was billed as a lower power version of the 919, but details about the exact differences are hard to come by. The 819 has a loudness switch in place of the attenuator (I think) on the 919.
I'm going with the 819 as my primary unit because its in better shape than my 919 and because it has the loudness switch. It will be interesting to hear how EW compares the 819 to other similar units, once he digs into mine.
Having owned the 717 and 517 series, I kept the 717 models and gave the AU/TU 517 to my brother. They are both terrific, and under most conditions there shouldn't be much audible difference between an 85 watt dual power supply amp and it's 65 watt similar sibling (and IMHO there isn't). The phono stage boards appear to be identical (and sound great). We had each tuner aligned (internally adjusted for lowest distortion, maximum separation and best sensitivity), and the tuners really are nearly identical internally (these Suis are just hard to beat for the $$). The amps are essentially the same design, with independent power supply boards and transformers. I tried both with the following speakers: Monitor Audio RS-6 (modern), KEF 103.2 (early Eighties British) and a pair of EPI 200C (late Seventies vintage). At moderate listening levels there really isn't much difference. Cranking the volume up to the loudest levels I listen at, the 717 seemed to have more headroom with the rather inefficient KEFs. I then sent the AU-717 to Dewick Repairs, and Terry rebuilt the power supply boards and generally spruced things up with Nichicon caps (from memory)as well as scraping off the glue that can acidify over the years. The large PS caps were all (four) fine. Anyway, this produced a Giant Step in listening quality, and I am sure that either model would benefit from this kind of attention. One more note: although the 717/517 is somewhat less inspiring in terms of build quality when compared to the 9900 and 9500, I personally think that they sound just as sweet once "rejuvinated", and they seem to be quite reliable (have owned three and a 719). Compared to the very nice 719, I think the 717 continued the "warm and tubey while not overly anyltical" sound of the 999/9500/9900 very nicely. Side by side, my 719 seems to be voiced a tad brighter, but not at all bad. I think there was a general trend that way with all of the Japanese builders moving into 1979-80 or so, and I guess some people prefer it. For me at least, the AU-517 / 717 (either) would qualify as Keepers, and same for the tuners. Sound commentary is subjective, but a LOT of people like the smooth sound of the Seventies AU models.
