I inherited this unit, which I thought was just a rebadge ADC ss 310, but the interior has a different arrangment, sort of upside down. Intermittantly makes a low rumble in one channel, not even sure its the eq, as it sits on top of Waynes preamp, which has picked up noise previously (pc psu noise through DAC I think, as rerouting usb to front port mitigated it), speakers are reasonably efficient ( Tekton Lore BE). So i need to figure that out, I'm not a tech though, more of a paint by numbers amatuer. Also would like to swap the red LED's for Blue on the sliders, but I think they may draw too much power. I know EQ's are a polarizing subject, but for me with this system and room, it is so much quicker and easier to adjust some of the low end than a digital solution, which I could use -but not as efficiently. Any thoughts?
I use graphic equalizers. Cheap to buy used and no software to update yearly when the flavor of cellphone changes. I won't buy anything but flip phone, the big screen of a smart phone is too fragile for my lifestyle. I can't see the screen either without reading glasses, which I don't take with me when I shop or commute.
You need to short the input and let the eq sit for a couple of days to see if it rumbles or not. Eq straight to the power amp, disinvolve the preamp. Plug a phone plug cable into the inputs and then short the tip to ring with an alligator clip lead.
When isolated to yes the eq, definite know whether left or right channel, then ready to open up. If the appliance is 20 years old or more, I would change the electrolytic caps on the side producing the noise without much thought. One or two at a time, then test you didn't make it worse. If you did damage it, you know just where the problem is, what you just did. I use >3000 hour service life ecaps so I don't have to do this job again in 7-20 years. Unspecified life e-caps are usually 1000 hours life. Mark the board for + with a sharpie before removal, if you put one in backwards it vents and shorts. I buy e-caps from distributors known for stocking real product. Newark & mouser. Digikey has a good stock but sold me a 9 year old e-cap as new once without any notification or discount.
More rarely a problem, film caps or resistors. More likely to get crackles & pops than rumble.
To identify which part is bad, involves sitting with a scope probe at various points in the circuit to answer the question: is the problem before or after this point? Extremely time consuming. A different eq for $60-80 would be in my future if it got this far. One with LEDs to indicate which frequency band is howling with mike feedback. A feature added right at the end before autokill was added to mixers.
You need to short the input and let the eq sit for a couple of days to see if it rumbles or not. Eq straight to the power amp, disinvolve the preamp. Plug a phone plug cable into the inputs and then short the tip to ring with an alligator clip lead.
When isolated to yes the eq, definite know whether left or right channel, then ready to open up. If the appliance is 20 years old or more, I would change the electrolytic caps on the side producing the noise without much thought. One or two at a time, then test you didn't make it worse. If you did damage it, you know just where the problem is, what you just did. I use >3000 hour service life ecaps so I don't have to do this job again in 7-20 years. Unspecified life e-caps are usually 1000 hours life. Mark the board for + with a sharpie before removal, if you put one in backwards it vents and shorts. I buy e-caps from distributors known for stocking real product. Newark & mouser. Digikey has a good stock but sold me a 9 year old e-cap as new once without any notification or discount.
More rarely a problem, film caps or resistors. More likely to get crackles & pops than rumble.
To identify which part is bad, involves sitting with a scope probe at various points in the circuit to answer the question: is the problem before or after this point? Extremely time consuming. A different eq for $60-80 would be in my future if it got this far. One with LEDs to indicate which frequency band is howling with mike feedback. A feature added right at the end before autokill was added to mixers.
Thanks for the reply. Im not sure if the intermittant rumble is the eq or from elsewhere, which makes it more annoying. I havent had time to even think lately, much less hunker down to figure this out. But, thank you for the advice, and I will post back, when I have more info.
Found my noise! Turned on system a last week and no output left side, which was where the noise was coming from. It was the F6, I had used shielded cable input from rca jack to amp board, and apparently the positive was not soldered as well as intended and had fully detached. 10 pm, saturday night, and I was resoldering, by 10:30 I was happy again! No more noise.