AU-717 with a slightly different Protection issue

[kevzep]

10 million dollar question . why did they design it in such a way ? answers on a postcard please .

Because it was the most cost effective way to do it with the existing circuit they use to drive the Protector with.

It's a cost cutting exercise, imagine the cost introducing a current limiting circuit, especially back in those days.....it would have made the amplifier very expensive...

 

[Hyperion]

The protection circuit for the AU-717 may seem to be a bit overprotective in these circumstances, but unless it's actually not working as its designers intended = faulty, it doesn't make sense to go monkeying with it. If the protection circuit is modified the user will just end up finding it easier to blow up the amplifier, or make it sound strained and harsh, and even damage the speakers themselves. This seems to be a clear case of not enough tolerance to a combination of low impedance load and (apparent) volume levels and load almost certainly not expected by its designers for ordinary day to day use. Our man likes it VERY LOUD and with 2 pairs of speakers, the AU-717 is the wrong amplifier for this combination.

I guess we nowView attachment 1229901 know why Sansui made the SP-5000 and SP-5500

90 & 100 watts and 102db

A solution to a temporary speaker driver overstock situation?

 

[restorer-john]

10 million dollar question . why did they design it in such a way ? answers on a postcard please .

Cost cutting. The AU-717 simply doesn't have the SOA in the output stage. Sansui should have run twice as many output transistors, but those Sanken diffused emitters/ring emitters were very expensive at the time.

Why not simply get another amp and run one pair of speakers from the '717 and the other pair from a cheap power amp?

 

[kevzep]

Cost cutting. The AU-717 simply doesn't have the SOA in the output stage. Sansui should have run twice as many output transistors, but those Sanken diffused emitters/ring emitters were very expensive at the time.

Why not simply get another amp and run one pair of speakers from the '717 and the other pair from a cheap power amp?

Yes, this is what we are suggesting....

 

[Overundr1]

Never realized that flamenco guitar players needed that kind of power
Seriously though, our band used to run over 10,000 watts of front end power and 800 watts to the floor monitors and that was for smaller venues, consumer audio equipment for the most part is just not designed for that kind of application, in my opinion sound quality was far more important to the designers than sound quantity. One JCM800 (or Fender evil twin in my case) would demolish the potential output from the 717 and probably have it self destruct in the process.
-Lee

 

[kevzep]

Never realized that flamenco guitar players needed that kind of power
Seriously though, our band used to run over 10,000 watts of front end power and 800 watts to the floor monitors and that was for smaller venues, consumer audio equipment for the most part is just not designed for that kind of application, in my opinion sound quality was far more important to the designers than sound quantity. One JCM800 (or Fender evil twin in my case) would demolish the potential output from the 717 and probably have it self destruct in the process.
-Lee

Well, on one side is the G22000 and the L7's, but behind me is my guitar rig....

 

[Overundr1]

Lol, no problem getting pinch harmonics in THAT room, egads, to my eyes a daisy chained super lead and JCM800 through dual 4x12 cabs, mighty fine sir, mighty fine.
Reminds me of a gig I stood in as the lead player, no rehearsal time mind you just get out there and do it, as we were about to go live watched the rhythm player turn around and set every knob on a hot rod deville to '10', and twas the night I left my earplugs in another guitar case, ears hurt for a week afterwards. Anyways, enough thread hijacking, back to the regular programming.
-Lee

 

[kevzep]

Lol, no problem getting pinch harmonics in THAT room, egads, to my eyes a daisy chained super lead and JCM800 through dual 4x12 cabs, mighty fine sir, mighty fine.
Reminds me of a gig I stood in as the lead player, no rehearsal time mind you just get out there and do it, as we were about to go live watched the rhythm player turn around and set every knob on a hot rod deville to '10', and twas the night I left my earplugs in another guitar case, ears hurt for a week afterwards. Anyways, enough thread hijacking, back to the regular programming.
-Lee

Very heavily modified amplifiers, sound nothing like a Marshall!! KT88 outputs completely re-designed front end, both amps with the same design, but even so, they still sound slightly different....which is nice...
But I digress, back to regular programming....