1) When you turn the pre on what do you now measure at the speaker outputs?
2) What do you measure across the outputs of the pre when it is not connected to F6?
I really am sleeping now.
2) What do you measure across the outputs of the pre when it is not connected to F6?
I really am sleeping now.
It might not be the pre, (Hopefully it is, but...) it could be a ground loop that’s finding itself through the input connections.
Drive the F6 directly from a phone, see if there’s hum.
Drive the F6 directly from a phone, see if there’s hum.
Yes..
The measurement should hopefully confirm this.
That's the intended the reason for requesting it.
The measurement should hopefully confirm this.
That's the intended the reason for requesting it.
It is pre. I've tried to limit ground loop as much as i can.
2 picoDumbs, I hope you were able to sleep a little. If you are working, ignore this. But I am transferring this conversation over to the B1 with Korg Triode thread. Hopefully, you will join us there.
Thanks
Take measurement across pre outputs when not connected to F6.
What do you get?
Is your Korg pre powered by a switch mode supply?
What do you get?
Is your Korg pre powered by a switch mode supply?
0v. nada!
Yes, it is a switching power supply.
RS-25-MEAN WELL Switching Power Supply Manufacturer
HTML:
Is your Korg pre powered by a switch mode supplyYes, it is a switching power supply.
RS-25-MEAN WELL Switching Power Supply Manufacturer
Ok
It's pointing towards a ground loop.
Are you using a thermistor in your F6 to break 0V from Chassis earth?
Still thinking to be sure
It's pointing towards a ground loop.
Are you using a thermistor in your F6 to break 0V from Chassis earth?
Still thinking to be sure
HTML:
Are you using a thermistor in your F6 to break 0V from Chassis earth?Yes.
I am using bridge rect for the pre to break the ground loop as well.
BTW, when i touch the input caps (10uf), it the hum becomes louder. May be the caps are not well insulated?
Ok
1) Turn off your F6
2) Disconnect from pre
3) Take a resistance measurement from 0V on the psu to the chassis?
What do you get?
Do this measurement for both F6 and your Pre separately
1) Turn off your F6
2) Disconnect from pre
3) Take a resistance measurement from 0V on the psu to the chassis?
What do you get?
Do this measurement for both F6 and your Pre separately
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Now connect F6 and Korg together via RCA (but not power cords connected) and measure from the F6 0V psu to Korg Chassis
Then have both rca and power cords connected to the wall (not turned on) and repeat the measurement.
As noted above the first measurement should have been 8.8 Ohms F6 0V to Korg Pre Chassis (RCAs connected)
Find out what is causing this issue and you will most likely fix your hum
Find out what is causing this issue and you will most likely fix your hum