AMB Laboratories DIY Audio Forums

[Rabbit]

Small update: The amps are working fine, and I resolved the audible whine emitted by the mean well switching power supplies by dialing up the voltage from 36v to 40v (after verifying in the design documentation that it is an acceptable voltage level for the amp.) I read about the audible whine fix on DIY audio from some others who use the same supplies in their amps. I never heard the whine except while powering the amps on and off, but I'm thrilled that it's hopefully gone for good.

[amb]

Yes, ±40V is fine, I actually measure around ±43V on my β24 with the Plitron transformer.

[Rabbit]

Hey AMB,

Is the Beta 24 an inverting amplifier? I think on my amp the output is out of phase with the input, and I've double checked my input and output wiring.

[amb]

β24 is non-inverting. If yours inverts phase, check your input and output wiring again.

[Rabbit]

I figured it out.

Input and output wiring: Fine.

Scope channel 2 invert button: Not fine.

[amb]

Haha!

[cobretti]

Happened to me as well......................