Audio-gd HE-9

I have this amp and I’m using it with my Audio Technica headphones without problem.My question is, I’m planing to buy Beyer Dynamics DT 990 Premium 600 ohm. can this amp drive those headphones with descent sound quality or not ?

Will the FX Audio DAC-X6 drive the Beyerdynamic DT 990 Pro 250 ohm headphones well to a good volume? Does the Drop for this include the power adapter. The description says power cord but doesn't mention the adapter so I wasn't sure. How does this item vary from the FX Audio DAC-X6 being sold on Amazon? Is this item produced by Shenzhen Audio? It seems like there are some counterfeits being sold. Thanks to all in advance for your help.

I'm interested in HE5XX and I only have Audient iD14 audio interface(the old model). So I'm curious if the headphone output of my audio interface is enough for HE5XX and other headphones like HD6XX of Sennheiser. Specification for the headphone output of Audient iD14(old model) is: MAXIMUM OUTPUT LEVEL: +12 dBu (0 dBFS digital maximum) DIGITAL REFERENCE LEVEL: +12 dBu = 0 dBFS OUTPUT IMPEDANCE: <30 Ω unbalanced VOLTAGE GAIN: +6 dB (optimised for loudness) FREQUENCY RESPONSE: ±1.0dB 10Hz to Fs/2 (load dependent) CROSSTALK: <-100 dBu @ 1kHz & 10kHz THD+N @ -1dBFS (1kHz): <0.002% (-94 dB) DYNAMIC RANGE: 108 dB un-weighted, 111 dB A-weighted MAXIMUM LEVEL into 30 Ω: +4 dBu 0.005% THD+N Power: 101mW MAXIMUM LEVEL into 60 Ω: +5 dBu 0.004% THD+N Power: 64mW MAXIMUM LEVEL into 600 Ω: +13 dBu 0.0025% THD+N Power: 39mW 1/4” TRS JACK: Tip (Left), Ring (Right) & Sleeve (Shield)

Will the Presonus AudioBox 22VSL 24-Bit/96 kHz provide the Sennheiser HD 6xx with the proper power for optimal sound quality or should I look for a different amp like the Schiit HEL (Will be using these headphones mostly for gaming)