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

Showing 4 responses by rrog

What speakers are you running with your AU-719? Sansui and other similar amplifiers from the late 1970's are rated for 8 ohms. Nowhere could I find a 4 ohm rating for these products. The speakers your AU-719 was designed to be used with have sensitivity ratings ranging from 92db to 105db. Depending on the sensitivity rating of the speakers you are currently running and the gain in your source half volume could easily be full volume.
Recordman

"I'm using the same set as I was with my other Sansui Amps, 8 Ohm speakers. I have not changed a thing, other than the amplifier."

Do they have a name on them? Check the back of the speaker. Sometimes there is a label with the brand and the model number.
Specs for Sansui SP-7500X are as follows:

16" woofer; 6 ohms
8" midrange; 8 ohms
6"x2" horn; 8 ohms
2" tweeter; 8 ohms
Stanwal, Please explain. I don't understand how the numbers you posted make you think the OPs amp is not working properly.

I think the easiest test would be disconnecting the second set of speakers and only running the Sansui SP-7500X, the speakers the AU-719 was designed for. This would be much easier than having the amp checked by a tech. The OP also mentioned in his post playing music at half volume which I assume is the 12 o'clock setting on the volume control. This setting could easily be approaching the amplifier's limit.

Although the model numbers are similar the amplifiers can be quite different on the inside and I believe the AU-719 was designed different than previous models.