WolfX700 Measurements of Topping Pre90/Ext90 Preamplifier/ Extender

[Red@]

The only devices that may have issues are the ones with small DC blocking caps at balanced output.
The ones that don't have caps will have zero issue no matter what output impedance is.
The ones that have 100uF or higher electrolytic caps will have zero issue.
Output opamp is not a concern, jellybean 5532 will drive 600ohm with zero issue. Let alone current lm4562, opa1612 etc.

Hello @JohnYang1997 can you please inform me if the pre90 would suffer from xlr conection from the Gustard x26pro ?

 

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The op-amps has a little bias current in A class, about 0.5mA. At 3Vp-p and 2k ohm load, we have 1.5mA, so, will work in AB class. With 10kohm will remain in A class.
The sound is not just SINAD score for static measurements. It's about the transients, it's about the power supply response in fact. At low input impedance the sound will be transparent but in the same time is a "flat" because the power supply will not be just as fast.

excellent explanation. Thank you. I was hoping to buy a pre90 since my x26pro has a DC coupled output stage with 100ohm xlr ouput. But I didn’t not realise the impact on transient response.
very helpful thank you.

 

[Veri]

excellent explanation. Thank you.

I'm really not so sure that explanation is correct or factual, at all.

 

[gvl]

I'm really not so sure that explanation is correct or factual, at all.

But nevertheless it helped to realize the impact on transient response!

 

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But nevertheless it helped to realize the impact on transient response!

Exactly