@Flisker A quick google search and I found this explanation:
“With OTL amps, the connected load impedance (headphones) makes all the difference. That’s not because of the impedance interaction - it’s because the headphone impedance combined with the output coupling capacitors forms a textbook-classic RC circuit . Such a circuit is frequency-dependent for current flow. IOW, frequencies too low will not pass (high-pass filter). In the case of typical headphone impedances, even 470uf means bass cutoff is beginning at about 110Hz. At 20Hz, it’s down by more than 1dB. That doesn’t sound like a lot, but remember that we’re used to ruler-flat responses in amplifiers from subsonic to almost 40-50KHz, or more. There are phase distortions that occur well above that 110Hz, meaning the bass is affected well into the range where 32 ohm headphones would be affected
For comparison’s sake, many OTL amps use only 220uf electrolytic output capacitors. They get away with this because they expect people to use high-impedance headphones with it
As you can see, even not counting for any phase distortions, bass is severely affected at almost every impedance except for 300 ohm.”
I 
% can confirm the 29 ohm Rad-0 does not sound good from the Elise. We talked about the Euphoria likely being a better fit, and Feliks also recommended it for your headphones. With that said… from one of our members…
@andris is selling his Euphoria if you wanted to try that route…