Reducing Function Gen output voltage

[sdp1234]

I have a BK Precision 3011B function generator but the amplitude of the signal is too high to input into the amp.  How do I knock the voltage down?  I used to do this several years ago but I've not used the scope in a long time.  What is the best voltage to use?  Seems like it was 200 mv?

[sluckey]

Just put a pot between the sig gen and amp. Wire it like a standard volume control. 200mv is good. Sometimes 50-100mv is good too.

[PRR]

.

[six el six]

I use the BK 3020 and it has attenuation settings of -10dB, -20dB, and an additional -20.

I don't know if the 3011 has those controls but they allow me to get an appropriate voltage on the 3020.

[sluckey]

I just looked at your function generator. Have you tried pulling the AMPL knob to knock it down by 20db? Another very easy way to knock the amplitude down is to get a BNC Tee and a 50Ω BNC terminator and put them on the output jack. Your gen puts out 20 V p-p (open circuit) or 10 V p-p (into 50 ohm load). Your amplitude control may get you low enough when the output is terminated.

 

[jjasilli]

Ditto.  here's the manual:  http://www.tech.uh.edu/college/labs/mgmt/Docs/Manuals/funcgen.pdf  Knob "#4" is the attenuator. I have an old tube signal generator with built in attenuator SW much like PRR's suggested circuit, and a pot to fine tune voltage within the selected range. You already have the pot and 2 ranges.  So, for less voltage I would build PRR's circuit in a little shielded box. 

It's also useful for some testing purposes to get down to the single milli-volt range of signal.  Then you can run signal > amp > speaker without hearing discomfort.

[sdp1234]

Thanks Guys,

I got it down with the pot but I'll go back and check the amplitude knob for the future.  This was real helpful to see when the distortions starts in each stage. 

[PRR]

> useful for some testing purposes to get down to the single milli-volt range of signal

True.