Hi, selling my HUM MA-1S portable class A amp. It has some scratches, as seen on the photos, but it's in perfect working condition.
It's unique in that it's a single-ended 4.4mm amplifier, so you should use it properly (not with 4.4mm balanced cables). I can include some custom-made single-ended 4.4mm male -> single ended 3.5mm male, and single-ended 4.4mm male -> RCA interconnect cables.
You can use your standard balanced 4.4mm earphone/headphone cables, and they'll work perfectly. It's just the interconnect that needs to be single ended.
It has a dead silent background in the low gain mode, so it’s suitable for sensitive IEMs as well.