Hum with voltage divider line out

[chuggy]

My 5f6a clone has a voltage divider line out (2.2k/100k) that carries objectionable hum.  The amp has minimal hum.  Any suggestions for hum reduction?

Thanks-
Jim R

[stingray_65]

My first guess would be that it is not caused by your amp.

I would tend to believe it may be your cabling between the DI and whst ever you are plugging it into.

other causes may be impedance miss match  and ground loops.

[PRR]

> miss match

I dated her once.

Actually what you want is a LOW impedance. But not so low that it drags on the source. What is the source? If it is a 4/8/16 ohm speaker feed, you could go down to 100 ohms total divider impedance without affecting the speaker. Then if 100K:2.2K was giving a good voltage, your new values could be 100:2.2 ohms. 2 ohms is an awkward value; also I suspect 100:2 or 50:1 is too steep a ratio for even a 5F6A. Try 220 ohms and 10 ohms. Or 2.2K and 100 ohms.

[chuggy]

Source is a 2 ohm output transformer.
Hum has persisted despite isolating the line out jack.
PRR et al- Why will the lower splitter resistor values suggested reduce hum?

Thanks-

Jim R

[HotBluePlates]

Why will the lower splitter resistor values suggested reduce hum?

Hum is due to a current, and current time big resistors equals big hum voltage. If there is a somewhat small hum current and you're using large resistors, lowering them will unleash a lot more signal current and drown out the hum. It will seem smaller by comparison. Or seen another way, it will result in a smaller hum voltage across smaller resistors.