Sansui Alpha 607 XR any good???

Elaborate on this, if you're willing.

I recall seeing a glossy brochure from Sansui, here on AK, that showed the B2301 and the B2101. It seems they said the Alpha Xs had kept the feedforward, and the double diamond differential technology.

This site talks about the progression of the technology, a little bit. http://www.sansui.us/HistProd.htm

I have reviewed schematics for several versions of alpha 907s and 707s, all of which are minor derivations of one another. None of them have any feedforward path in the power amplifier, and there are no feedforward components installed. As I said in one of my posts about Quadklipsch's 707X I think there would be significant difficulty in an x-balanced amplifier to measure the output distortion and then decide which half of the circuit should be corrected by injection of the inverted distortion signal.
 
Yes you are right. The super feed forward was used on AU919 ,AUX1,only.
It is rather impossible and useless to be implemented on ax balanced circuit .
 
^^^link doesn't work.

I appreciate being corrected regarding Super Feedfoward, that it's not part of the X Balanced amps.

Super Feedforward was used in several models of the AU-D series (AU-D22, AU-D33,AU-D55,AU-D77).

I don't have any opinion about Super Feedforward, haven't heard any of those amps.
 
^^^link doesn't work.

I appreciate being corrected regarding Super Feedfoward, that it's not part of the X Balanced amps.

Super Feedforward was used in several models of the AU-D series (AU-D22, AU-D33,AU-D55,AU-D77).

I don't have any opinion about Super Feedforward, haven't heard any of those amps.

Maybe it's a region thing? Basically the article says that this Super feed forward technology is so revolutionary it drops distortion to almost unmeasurable levels that even measuring equipment can't detect. And in a listening panel test, it was marginally perceivable over "another first rate amplifier" on some music with complex passages. The NYT concludes that such a technological "tour de force" must be appreciated, even if it's just an exercise in "gilding the lillies". The amp cost $1000 in 1981!!!

The article reads that this was the first time super feed forward concept that was originally devised for across the sea cable communication had been successfully applied to an audio amplifier...which was the great achievement of this amp
 
And so the 607 XR is not going to be any better than the aud 11II ?
Anyone

If you care about the sound, and like how these x- balanced amps sound, then it's a good buy. If you are a collector, then the AU-D11 II is more valuable. The late model alpha 607 series are a great value based on how great they sound and can now be had for less than what a older 70s Sansui gear goes for
 
I like the feel and looks of the 707x . I have developed this love for it after listening to it for all these weeks.
The 607XR has the modern looks and a very classy built.
If the sq isnt any lower tham the 707x , id consider buying .
 
I have reviewed schematics for several versions of alpha 907s and 707s, all of which are minor derivations of one another. None of them have any feedforward path in the power amplifier, and there are no feedforward components installed. As I said in one of my posts about Quadklipsch's 707X I think there would be significant difficulty in an x-balanced amplifier to measure the output distortion and then decide which half of the circuit should be corrected by injection of the inverted distortion signal.

If you happen to have schematics not commonly available please let us know. Here is my list of what I have
 
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