why does a relay attenuator sounds much worst than an alps black ?

[lcsaszar]

I might take you up on that... we'll see.

Carla at YourManualSource is looking right now. Never hurts to have a factory original... keeps the price strong if I choose to unload it down the road.

Have you found this to a good and effective toy?

I ask because I calculated 0.24% THD for my gizmo... and I am measuring 0.237% with AA501. That happens so rarely in my world... makes me wonder.

😀

poobah, I have a Tek AA501 with IMD option and an SG505 also with IMD option, both with full (paper) service manuals. This is my primary audio test gear, I can measure THD/IMD down to 0.001% within 10Hz to 100kHz... The dB zero reference function is also very useful. I killed the input a few times but no worries, its plain NE5533AN in socket... Drop me an email if I can help. Laszlo

 

[poobah]

Thanks Laszlo...

So I guess OPTION 1 is the IMD measuring function? I have since noticed that not all AA501's have the pushbutton for IMD.

I bought this in somewhat of a hurry... need it to spec out a new product. Don't worry my 0.2% distortion is not audio gear!

I'm glad to know that people get good results with this unit.

😀

 

[lcsaszar]

Yes, Option 1 is IMD. At IMD measurement the SG505 oscillator gives out 60 Hz or 250 Hz (internally selectable) and the variable frequency (set by the dial on the oscillator) mixed in 4:1 amplitude ratio. AA501 is intended for operate with the SG505 oscillator, but I suppose you can replace it with any low-distortion signal source.