Rolling Op-amps in Gustard H20 Headphone Amplifier

[maxxevv]

Interesting! So what would the SINAD numbers on balanced output for the amp be if it were 4Vrms (dashboard here shows 10Vrms ) since that seems to be the de-facto XLR output values we seem to see most often?

You only showed the 5Vrms output for single ended on the original review. Just noticed that there were no Balanced output readings there though ?

 

[Ralf Stocker]

Is this 26dB drop coming out of the device or is that the radiation on the unbal cable from the device to the AP?

 

[maxxevv]

Is this 26dB drop coming out of the device or is that the radiation on the unbal cable from the device to the AP?

Different output Vrms values will differ the THD+D as well as SNR numbers for the same machine measured.

Different sets and different output designs will vary differently with Vrms output values. So only way to be sure what comes out is really measure them. Can't really reliably extrapolate based on Vrms values unfortunately.

 

[ke4iog]

One reason for the 'specialty' op-amp to get that hot, is self oscillation that is out of the measurement band. Unless the open loop gain is properly compensated for, self oscillation is always a possibility. Swapping op amps with possibly wildly varying specs is an invitation for trouble. As an instrumentation engineer for the last 40 years, a lot of thought goes into selecting the correct parameters of a particular opamp for each measurement.

 

[Ralf Stocker]

I would call that engineering fail. Why substitute a highly integrated OP with a discrete circuit that oscillates much easier?

 

[deafenears]

Interesting! So what would the SINAD numbers on balanced output for the amp be if it were 4Vrms (dashboard here shows 10Vrms ) since that seems to be the de-facto XLR output values we seem to see most often?

You only showed the 5Vrms output for single ended on the original review. Just noticed that there were no Balanced output readings there though ?

@amirm , do you still have the H20?

 

[amirm]

@amirm , do you still have the H20?

No I do not

 

[Hypnotoad]

However opamp is just like any other components. It's a choice, a selection according to the need. Of course it will make a difference in some applications.

Indeed, otherwise we would only ever need NE5532's.