Hi All,
My Quad 606 have slight buzzing sound from right speaker channel and sound distortion from left speaker channel. When I do my research, I found that it is common issue for 606, but I can't find anyone post about solution for this problem.
Does anyone found the solution?
Thank you
My Quad 606 have slight buzzing sound from right speaker channel and sound distortion from left speaker channel. When I do my research, I found that it is common issue for 606, but I can't find anyone post about solution for this problem.
Does anyone found the solution?
Thank you
Some duplicate posts have been removed. Please refrain from cross-posting.
If the buzzing is 120 hz ( western hemisphere) or 100 hz (eastern hemisphere) then you're hearing ripple from dried up rail caps, likely. Other frequencies, could be an oxidized internal connector that needs to be removed & replaced. Or sometimes, an oscillation that has to be tracked down with a scope. You can check the ripple on the rail caps by looking for AC voltage. Should be <50 mv. Not measurable on meters with lowest AC scale 200 vac.
Distortion caused by clipping is frequently dried up rail caps. Distortion caused by not enough highs or lows can often be dried up coupler caps. Distortion caused by a bad solder joint or a bad weld in a capacitor resistor or semiconductor, much more difficult to track down.
This amp is what, 25 years old? Electrolytic caps are rubber sealed aluminum cans filled with water slime. The cheaper ones the rubber cracks, the water leaks out, they dry up & stop performing. The expensive forever epoxy sealed ones, no consumer product has them. You are supposed to throw your amp away and buy a new one every 6 years (these days). All that waste is hard on the planet. I fix them.
You can prove the rail caps are bad by buying a 8 or 4 ohm resistor of the wattage > the amp rating, and measuring the maximum voltage out on the resistor while playing music from a radio or something. You have to use an analog voltmeter or a scope, cheap DVM make random numbers on music on the AC scale. P=(V^2)/z where z is 4 or 8. P<rating of the amp, your rail caps are dried up.
You can also remove caps and check them with a $120 ESR meter, but all the caps in the amp won't be $50. Not worth the bother of buying that meter, IMHO.
I like to buy electrolytic caps rated 3000 hours service life or higher as the store shelf grade (500 to 1000 hours) required replacement every 6-8 years in my ST70. Do it once & forget it. Buy caps from an authorized distributor, not ebay or alibaba. Farnell & digikey let you see the hours service life in the selector table. Caps over 2200 uf will be snap in, not leaded. Separate selector table.
Mark the plus of old caps on board with a sharpie before removing ; if you put new ones in backwards they blow the seal. Wear safety glasses, solder can splash in the eye. Don't work with the AC plugged in. No jewelry on hands or neck.
Don't replace more than 2 caps before a sound check. Newbies make a lot of soldering errors and if you replace two and it gets worse, you know just where the problem is without analysis.
Happy learning. Good fortune.
Distortion caused by clipping is frequently dried up rail caps. Distortion caused by not enough highs or lows can often be dried up coupler caps. Distortion caused by a bad solder joint or a bad weld in a capacitor resistor or semiconductor, much more difficult to track down.
This amp is what, 25 years old? Electrolytic caps are rubber sealed aluminum cans filled with water slime. The cheaper ones the rubber cracks, the water leaks out, they dry up & stop performing. The expensive forever epoxy sealed ones, no consumer product has them. You are supposed to throw your amp away and buy a new one every 6 years (these days). All that waste is hard on the planet. I fix them.
You can prove the rail caps are bad by buying a 8 or 4 ohm resistor of the wattage > the amp rating, and measuring the maximum voltage out on the resistor while playing music from a radio or something. You have to use an analog voltmeter or a scope, cheap DVM make random numbers on music on the AC scale. P=(V^2)/z where z is 4 or 8. P<rating of the amp, your rail caps are dried up.
You can also remove caps and check them with a $120 ESR meter, but all the caps in the amp won't be $50. Not worth the bother of buying that meter, IMHO.
I like to buy electrolytic caps rated 3000 hours service life or higher as the store shelf grade (500 to 1000 hours) required replacement every 6-8 years in my ST70. Do it once & forget it. Buy caps from an authorized distributor, not ebay or alibaba. Farnell & digikey let you see the hours service life in the selector table. Caps over 2200 uf will be snap in, not leaded. Separate selector table.
Mark the plus of old caps on board with a sharpie before removing ; if you put new ones in backwards they blow the seal. Wear safety glasses, solder can splash in the eye. Don't work with the AC plugged in. No jewelry on hands or neck.
Don't replace more than 2 caps before a sound check. Newbies make a lot of soldering errors and if you replace two and it gets worse, you know just where the problem is without analysis.
Happy learning. Good fortune.
Last edited:
When I do things wrong and my wife smacks me, I hear the same frequency buzz in both hemispheres... go figure...
Sorry, just trying to be funny.
Sorry, just trying to be funny.