Nothing plugged into the inputs.bmkuter said:
How old is the wiring where you live? Do you have grounded outlets? You may want to try attaching a wire to the chassis of the SEX and the chassis of your source.bmkuter said:
Quiet Hum?
- Thread starter bmkuter
- Start date
Hum exists regardless of inputs.
I would say the wiring is maybe 15 years old at most. The apartment building is relatively new, but at least a decade old. The hum is most noticeable with low impedance headphones, especially my IEMs. The power should be grounded, and I'm plugged into a Furman Power Conditioner (got it very cheap and I needed another power extension in my house).
I would say the wiring is maybe 15 years old at most. The apartment building is relatively new, but at least a decade old. The hum is most noticeable with low impedance headphones, especially my IEMs. The power should be grounded, and I'm plugged into a Furman Power Conditioner (got it very cheap and I needed another power extension in my house).
And just to confirm, with the amp on and the volume control all the way down, is it detectable with IEMs? (and is the amp wired for 4 ohms?)
Could I see a side photo of the terminal strip with 23-28?
I just wanted to make sure the shoulder washers were in place. If a shoulder washer is missing from one of the terminal strip terminals with a plastic acorn nut, you could end up with some hum.
It could be loose hardware, it could be a power line problem (still seems unlikely in your case), or external interference. You're certain 36L isn't touching the power transformer mounting nut right?
Even for me to get a proper noise floor measurement when testing the prototype SEX 3, I had to wait for a day when everything was super duper quiet.
Even for me to get a proper noise floor measurement when testing the prototype SEX 3, I had to wait for a day when everything was super duper quiet.
Yup, just that.bmkuter said:
If there's something nasty riding on your powerline, it may be getting into the power supply, which would be a noise that would be there regardless of volume knob position usually.bmkuter said:
An attenuating headphone adapter may be useful here if the noise persists.
Paul Joppa
Moderator
Take the output from the speaker terminals, to start with. If your scope is sensitive enough, you can quantify the hum and noise. Short the input (a shorting RCA is best, but usually just turning the volume all the way down is equivalent).
There is no 370K resistor in our inventory, and only one carbon film 1W resistor in our inventory. What color codes do you see on yours? Did you measure the resistance with them before you installed them?
In any event, as long as they are both about the same value, they could be 200K or 500K and it wouldn't make much of a difference.
In any event, as long as they are both about the same value, they could be 200K or 500K and it wouldn't make much of a difference.
If you have a tone or music playing through the amp, then yes, you will hear some very low level noise coming out of the amp. If nothing is playing and you hear something like the power transformer buzzing, that would tend to suggest that the hardware is loose or there could some DC present on your AC mains that causing a bit of noise in the power transformer.
It's a possibility.
