What do folks expect with cheap crap like that. Just add to landfill sites. If you can afford £300 plus HP's spend a little on something decent.
I own both the A10h and A20h and they both work for me with no problems.
But when I bought it, I was already aware that these products save on development costs, but above all on quality control and support.
The decisive factor was clearly the relay-based volume control and, with the A20h, the balanced option.
If you look at what these devices cost the buyer on sale, after deducting all taxes and duties, the seller's profit, transport costs, etc., then you have to ask yourself how the manufacturers manage to finance the production (components, circuit boards, assembly , housing, power packs, cables, packaging, proportionate costs of the company, etc.). And that's not even counting the high development costs.
But I've had a Violectric headphone amp on my desk for a very long time, and it will only make room for a newer amp from this manufacturer.
This manufacturer has been building high-quality devices for over 35 years and places great value on development, product quality, quality control, warranty and support. And quite apart from the excellent and personal support, you can give your devices for repair even after 30 years. There aren't many manufacturers that have had their devices in use for so long.
But with the good sound quality, functionality and reasonable prices of the L30 (II), Sabaj A10h/A20h, etc., who is willing to pay that much more (more than double) for quality and support?