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SANSUI AU-719 Gets Really Hot?

I recently acquired a Sansui AU-719 which gets extremely hot. I have other Sansui's (AU-417, AU-517, AU-717, AU-7700, Etc.) and though they do get warm, none of them get anywhere near as hot as the AU-719. I listened to it for about 6 or 7 hours the other day (I only listen to vinyl) and as happens from time to time, after a few beer, the volume tends to go up:) Still never exceeded half volume and it was more than loud enough (think the neighbours hate me now), yet it got extremely hot, so hot in fact, that I could not keep a finger on it for more than a second or two for fear of actually getting burned. If this is normal for this model then I can hook up a small fan near it to help dissipate the heat. Today I've had it on for about 2 hours at just less than 1/4 volume and it is a bit warm but by far not too hot. I tried researching this on line and found two opposing points of view, some said it is normal while others said that the excessive heat probably indicates a problem which if it not fixed, could fry the amp. Any input would be much appreciated, thanks;
Denny
recordman34
rleff
1,065 posts
 
I would suspect filter caps that have dried up some and are becoming resistive producing heat as well as output transistors that maybe seeing a higher bias than they should be and heating as well.
recordman34 OP
7 posts
 
Thanks again, I'm going to try to get someone to look at it as I discovered another problem last night. The Tone Defeat switch works just fine in the "Defeat" position" but in the "On" position the right side cut out on me (although it had been working just fine in the "On" position up til then). I cleaned it prior to hooking the amp up last week. I tried it again this morning and once again the right side cut out so I moved the switch up and down quite a few times and sometimes all four speakers would work, sometimes just one side would work and a couple of times neither side would work (while in the "On" position / all four speakers seem to always work in the "Defeat" position though). I don't think that has anything to do with the excessive heat but as I'm finding out, this unit has some issues. Later today I'm going to try it with just two speakers and see if that makes a difference with the overheating issue, then I guess I'll just have to hook up one of the other ones for a while and see about getting this one fixed, Thanks again for all the help, I really appreciate it because if you haven't already noticed, I'm not exactly technically inclined when it comes to these things:)
recordman34 OP
7 posts
 
Just listened to it for about 40 minutes with only the two main speakers hooked up and it still gets extremely hot. I had the volume at less than half (or at about 11 O'clock). Time to hook up a different one and once again, thank you for the help.
recordman34 OP
7 posts
 
I don't know if this is worth mentioning but I unhooked the 719 and hooked up my little 417 and it is driving all four speakers without breaking a sweat, it is barely warm.
stanwal's avatar
stanwal
3,147 posts
 
What they indicate is that the amp should have no trouble driving 4 or even 2 ohm loads. Amps that have trouble with lower impedence loads see their power stay the same or decrease as the impedence falls. The Sansui's rise in power indicate that they should handle lower impedence loads. The OP's last post seems to be vindication enough for my position. The smaller 417 has no trouble, the 719 does; ergo the 719 is not opperating properly.
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