DENON 480r amp..at least 10 years old..but over time the right channel is quieter then the left and i have to use the balance control to correct the image .seemed an intermitent fault at first but now its like it all the time!
seems like a common problem with some denon amps bulit around this time. since it seems it was a common problem..is there a common fix for it? dry joint? replace a component?
i would love a new amp but cant afford it! so out with the screwdriver and soldering iron!
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Re: Lower volume on right side!
I have't seen this porblem, have you tried changing the source place's R with L and see if the sound have change side. If it did then it's your input signal.
I would first check the board for bad solder connection, but it sound like you have a cpu problem or the main ic's procesor. This can be checked with a scope with the ouput of the pre amp to see if the level or the same, with a mono input signal only. You may also have a section of the ouput stage not working, the pre amp , the stage before the main amp out will tell you all by looking at the signal level's.
II know it's not easy, but you will at one point need a scope, without it you will notice you're just going at it blinfowled. When purchasing a scope, put the money it it, a good scope will cost a min of $2k. I'm usind a teck scope and love it, I've also used a leader and find it just the same and sometine better for under $1k.
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Did you try to switch the loudspeakers? Before changing anything always lover the volume and switch off the amplifier. Assuming you tested already different inputs, you can be sure no cable from signal source is out or defect. (or did you nit check that first?). When the amp is switched off, disconnect the speakers and switch left to right and right to the left output.. If the other speaker is quiet now, you are sure it is in the amp. Still his can be anything. You can check the connections between the pre and main amplifier on the back side. When you have an extra set of interlink cables, perhaps you can cross the in and output there too. Take care every time you change something, lower the voltage and switch off the amplifier. Sudden clicks when switching on or changing anything can damage the amp and or the speakers.
Perhaps when you checked this you can locate where the problem is? Speaker, speaker cable, power amp, pre amp, (only a part of the pre amp.
YOU ARE NOT RIGHT IT SHOULD GIVE AT LAEST A LOW VOLUME SOUND WITH A LOT OF DISTORSION AND A CRACKING NOISE IF DOES I GUESS THAT YOU HAD THIS AMP IN A PLACE WITH A LOT OF HUMIDITY AND YOU HAVEN'T WORK IT FOR SOME TIME IF I AM RIGHT PUT YOUR AMP IN THE SUN AND WORK IT FOR 10 MIN WITH A 5 MIN BREAK LET ME KNOW THE RESULTS
no reason why not, 3 channel amps used to be the "state of the art" back in the early stereo days. the third channel was produced from the sum of the right and left channels, (the plus side of the right and the plus side of the left were sent to the center channel. produced what was considered at the time a true reproduction of the sound as it was intended to be. your lucky to have this old amp.
The good news is that it's in one channel, which means you have the right channel parts to compare it with. Now the bad news whatever causing it and it's likely to be a semi-conductor (transistor or IC) has to be replaced. However finding it is easier than you might think. For a start it's going to be hot to touch. And you can get get it to stop being hot, while the amps on, so correcting the fault, for a while. You do this by spraying it with Servisol Super Freezer spray. You have to have the amp running for this. Find the left channel amp and wait while it goes bad. Then spray (one at a time) any part you suspect. If the sound returns to normal, you have found the faulty part! To prove it spray the same in the right channel. That shouldn't change.
You can get the freezer spray from your local electric parts shop (such as Maplin UK).
Just have a look around first. Remember the left channel will be the same as the right, so if it doesn't look the same in the right as the left you have the cause of the problem. Resistors are good at causing it, but transistors can too.
HI , just found your post . I also have just picked up a denon DAP-2500 pre and 2 POA 4400 amps with klipsch belles, having same probs with power balance i followed some helpfull advise and deoxidized all rca jacks speaker terminals ect. also i opened the pre amp and cleand it even though it was fairly clean, i used cleaner on all switches and volume controll's . WOW I could hear it nice and clean . Next i will clean the amps. hope this works for you as this is great equpment well worth saving.
I have one of these exact amps, more than likely its the volume pot that will need a clean with some WD40 to clean the dust build up inside, try putting the balance on that channel alone and turn the volume up, if the sound kicks in or trys to kick in, this will be the problem or the track inside the pot maybe very worn on the lower setting, which will need then replacing, remember these amps are around 40 years old and chances are it has done a lot of work, if this doesn't fix the problem, as the previous post said it may be in the power amp section and could just be a dry joint on any of the componets, you can pick up all the componet parts fairly easily and cheaply nowdays anyway, let me know how you go.
I would check out whatever drives the left channel first. If it is a transistor, you can put a ohm meter on the terminals and see if it shows a short (amp turned off). If there are two transistors for the left channel, and you find a short on one only, replace the other to be on the safe side.