minimum load impedance for DIY opamp

[F1 FAN]

I'm curious as to what the minimum loading requirements might be for the 2SK389 diff stage/ 3310 follower circuit depicted in fig 16 of Nelson's DIY opamp article? http://www.passdiy.com/pdf/diyopamp.pdf


Thanks

 

[Nelson Pass]

It will be limited by R3 in terms of voltage swing. As
a concept it will drive any impedance, with output level
limitations.

😎

 

[F1 FAN]

Thanks Nelson.I'm using a pair for preamp duties and I think they sound very good but wanted to be sure they were OK with <10k loads should I encounter such an amp in the future.