I recently bought a Marantz 2220B Am/Fm Receiver. I am running all four channels at the same time (Both Main & Remote). It sounds fine at lower volumes however, when pushed to about half the volume it starts to pop and crackle especially with music that has deep bass parts (Like kick drum). Quite annoying, considering it's a unit that is in otherwise great working condition.....just can't put the volume to loud.....and i know it has the power to do so. PLEASE HELP!!
The most likely cause of this is some DC current working its way through the system. WIthout taking some measurements, it will be difficult to confirm this though. This should not be an expensive repair. Figure on $20 or so for parts (capacitors mostly).
Dan
Before you start messing with those adjustments, please chec the voltage readings in the area of H701-704. Verify that these transistors are good. The typical failure is of the diff-amps and these pairs of transistors form the diff-amps for each channel. IT is more likely that these are noisy rather than just an adjustment.
Keep me posted.
Dan
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The amp is ok, you have to low imp on the speakers. The amp has only got 2 cannels and with both main and remote at the same time you get half the imp off your speakers. Ex 4 ohms speakers vil be 2 ohms for the poweramp and that´s to low. If you have 4 speakers running at the same time they must have an imp of not lower than 8 ohms.
Sorry for my bad english
Mole in sweden
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Thanks Dan!! Your help is much appreciated. I have a friend with equipment that should be able to test the DC current. I downloaded the service manual for the 2220B receiver, it mentions something about sound clipping. Sounds like that might be my problem. The manual says to replace or adjust resistors R711 & R712 (I believe these are for output)....i'm no tech so i have no idea, just grasping at straws. I'll have to get it tested.
Thanks for the your comments.
I most likely won't get a chance to look at it for about a week, my friend with the know how and equipment is moving. Once he's settled in, i'll get him to have a look. I'll keep you posted though.
Thanks again for the advice!
Talk soon.
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