So I just bought an adcom 5503 amplifier. It does work and sound ok but it runs very hot even while on very low levels. Also there is a horrible buzz sound coming from the toroidal power supply.
First off ill tell you about the temps. All 3 channels are within 5 degrees F of 125. Now it does take a few hours to get that hot but it still does. I started with a cold amp the other day and played music at a pretty decent volume and it didn't get that hot, so it is something that is taking a while to do. From what I have read its probably a slightly high bias maybe?
Now about the buzzing toroid. It is a pretty decent buzz coming from the front of the amp. It is affected by turning on my av receiver. As in it will get loud then go back down when I hit the power. I tried a 3 to 2 prong adapter to rule out ground issues and it made no difference. Also there is a hiss in my tweeters that sounds just like the buzz.
Another thing that I noticed was that the power light doesn't stay on long after the power is turned off. I have a 555 Adcom that the power light will stay light for like 30 seconds before going out. The 5503 might stay on for 3-4 seconds. Could this mean there is a bad capacitor? And maybe it is causing the toroid to buzz? Just a thought.
I did measure the dc offset and the L/C/R measures 9.4/14.4/27 mv. My plans were to tear it down and look over the components for obvious damage, bad solder joints and maybe take the big capacitors out and take them to be tested. I will clean everything up and set the bias and dc offset and see what the result is. Is there a way to test the toroidal transformer? Or if I took it with the caps maybe a shop could test it? Any ideas what's going on here? Any help would be appreciated. Thanks mike.
First off ill tell you about the temps. All 3 channels are within 5 degrees F of 125. Now it does take a few hours to get that hot but it still does. I started with a cold amp the other day and played music at a pretty decent volume and it didn't get that hot, so it is something that is taking a while to do. From what I have read its probably a slightly high bias maybe?
Now about the buzzing toroid. It is a pretty decent buzz coming from the front of the amp. It is affected by turning on my av receiver. As in it will get loud then go back down when I hit the power. I tried a 3 to 2 prong adapter to rule out ground issues and it made no difference. Also there is a hiss in my tweeters that sounds just like the buzz.
Another thing that I noticed was that the power light doesn't stay on long after the power is turned off. I have a 555 Adcom that the power light will stay light for like 30 seconds before going out. The 5503 might stay on for 3-4 seconds. Could this mean there is a bad capacitor? And maybe it is causing the toroid to buzz? Just a thought.
I did measure the dc offset and the L/C/R measures 9.4/14.4/27 mv. My plans were to tear it down and look over the components for obvious damage, bad solder joints and maybe take the big capacitors out and take them to be tested. I will clean everything up and set the bias and dc offset and see what the result is. Is there a way to test the toroidal transformer? Or if I took it with the caps maybe a shop could test it? Any ideas what's going on here? Any help would be appreciated. Thanks mike.