Both signal generators got an output impedance of 50 Ohm.
The UDB can generate 3.535 Vac at 50 Ohm that drives 70.7 mA through a short circuit.
The data sheet of the used IC says the amplifier can drive 75mA max.
So no problems with your LED's if you look at the current.
But the UDB can only generate +-5V dc output max.
For your 6-7 Vdc you need the XM generator.
For more details, please check: