G-33000 fan turned on again...

tobyj17

Comfortably Numb
Yup.. it happened. Working on the house listening to the radio at a fairly high level (100 watts or so rms) and noticed that after awhile the fan on the power amp was on.

Last time this happened the bias and offset were way out of whack. It's had a recap with Nichion caps since then. The bias and offset was checked about a year or so ago and it was fine. I'm using a pair of KEF reference 4.2's that are four ohm speakers.

What do you guys think..was i pushing it too hard or do you think something is going on?
 
I think it was doing what it should… 4 ( ish ) Ohm speakers 100 watts … see how it behaves under .. Non WARP drive if the fans come on @ 20 watts, yea you have an issue… if not your good.. Do you have a Laser thermometer ??
 
I have an easy thermometer, my hand. If it is hot to touch the heat sink there is a problem.
Try to connect both speakers in series , so 8 ohms , and run it the same way. See what it does.
If sansui is right in the manual , then it probably is pushing 200 w , at 4 ohms , so it might be normal.
 
Yup.. it happened. Working on the house listening to the radio at a fairly high level (100 watts or so rms) and noticed that after awhile the fan on the power amp was on.

Last time this happened the bias and offset were way out of whack. It's had a recap with Nichion caps since then. The bias and offset was checked about a year or so ago and it was fine. I'm using a pair of KEF reference 4.2's that are four ohm speakers.

What do you guys think..was i pushing it too hard or do you think something is going on?

How hot Toby? Can you hold your hand on the heatsinks without getting burned?

I suspect if it got too hot it would trip the thermal protection.......
 
Kev if the heatsink is so hot that burns hands, I suppose it's 60 Celsius and up , the heat sink , outer one , which means transistors might have gone up to 80 Celsius . If toby hasn't applied thermal paste on outside heat sinks , then he's got an issue. Right?
My g 22000 the modified one , with the 8 tr's per channel, and the thermal paste on the outer heat sink , rarely goes really hot but I haven't been able to turn the fan on , even at 200w for more than an hour.
 
When I've tested G-22000's and 33000's here, I run them with a 1KHz signal at about 50W output into 8 ohms for about 1/2 an hour and the fan will kick in.
 
Kev if the heatsink is so hot that burns hands, I suppose it's 60 Celsius and up , the heat sink , outer one , which means transistors might have gone up to 80 Celsius . If toby hasn't applied thermal paste on outside heat sinks , then he's got an issue. Right?
My g 22000 the modified one , with the 8 tr's per channel, and the thermal paste on the outer heat sink , rarely goes really hot but I haven't been able to turn the fan on , even at 200w for more than an hour.

Yeah sure, I see what you are saying.........We'll have t wait and see what Toby has done to it in the past, I think he may have had the heatsinks off at some point when there was a fault a while back......
 
Toby , first chance you get , unscrew the six hex's on each heatsink and apply some thermal paste all over the area where it gets in touch with the internal" heat sink" .It will help your heat sink dispose temperature more quick and more effective.
I suppose the thermal paste on the output tr's is fresh and not the one from original assembly.
 
When I've tested G-22000's and 33000's here, I run them with a 1KHz signal at about 50W output into 8 ohms for about 1/2 an hour and the fan will kick in.

That's funny.
No :no:


this is funny

Toby , first chance you get , unscrew the six hex's on each heatsink and apply some thermal paste all over the area where it gets in touch with the internal" heat sink" .It will help your heat sink dispose temperature more quick and more effective.
I suppose the thermal paste on the output tr's is fresh and not the one from original assembly.
 
Well each one defines funny in his own way.
It's more or less like what clint eastwood had said about opinions.
 
I could touch the heat sinks, but not for long- a second or two at the most. It was definitely hot, but it wasn't in protection. Sound was also nice and clear, no issues that I noticed other than the fan running. I know it's there for a reason, but i know most can't get it to come on.

Joe, I took your suggestion awhile back and applied the thermal paste where you said to. I don't have a temp gun to test with either.

The Kef's are a pretty hefty speaker, two 10" woofers, three mids and a tweet all in one cabinet. They're four ohm and I'm not real sure what the efficiency is..mid 90's i'd guess.
 
Seems to me that if your bias and offset are OK -the fan is doing what it was designed and installed in there to do ---Cool the unit as needed.
 
Perhaps you'd like to expound on that comment. I fail to see any humor in my previous post. I merely presented my own method of testing to see that the fan will engage when the amp warms up.

Funny in a sense as strange.
Not humorous.
 
OK.

Why is it strange? At 50W output I'm able to monitor the heat rise and the point where the fan kicks in a lot easier than if I was running it at a higher level. Maximum heat generation would be at about 1/3 of full output power, but I like to see the heat buildup happen a bit more slowly.

Playing music at a perceived level using the power meters and playing a constant sine wave with a precise level set with a wideband AC level meter (in this case a distortion analyzer) are two very different things to the amplifier. Music is a much easier load.
 
Playing music at a perceived level using the power meters and playing a constant sine wave with a precise level set with a wideband AC level meter (in this case a distortion analyzer) are two very different things to the amplifier. Music is a much easier load.
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YES i totaly agree with this. Never said the opposite.

Why is it strange? At 50W output I'm able to monitor the heat rise and the point where the fan kicks in a lot easier than if I was running it at a higher level. Maximum heat generation would be at about 1/3 of full output power, but I like to see the heat buildup happen a bit more slowly.
Here is my disagreement. In 1/3 of full output. How did you measure this?
I tried to reproduce the same situation , with a four ohms dummy load , able to suck all the power from g 22k , not at 1khz , but at 400hz. At 50 watts , it never got hot. Not talking about the fan kick in. I measured some 50-55 celsius on the outer heatsink.
Fan kicks in at 65 celsius in this unit. So it looks a bit strange to me.

On a normal g33k my brother in Law has , when i reapplied thermal paste to the outputs , and applied thermal paste to the outer heatsink , and did the same check , got similar numbers.
When I wanted to push it really hard and turn the fan on , I fed a 50 hz sinus signal from the generator at 100w , for a quarter of an hour. It went crazy , fan would not turn off in anyway. I had to turn the volume down or the thermal shut off would intervene.
Now that is a hard test . I think.
 
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1khz is the industry standard to test equipment at, it's what I bench test at- sine and square if I really want to hammer it.
 
It is doing what it is suppose to do...I've had my G330000 for 30 years and when I push her the fan comes on....:thmbsp::music:
 
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