redgum audio rghd headphone amplifier

I can't answer your question, because I have no experience with the the Redgum. However, if you are looking for a solid state headphone amp, you should add the Sugden Headmaster to your list. Also, you might check HeadFi and Headwize for opinions on the Redgum.

Do yourself a favor and check out the Gilmore V2 and V2-SE as well. I switched from tubes (Audio Valve RKV Mk II) to the V2 and have a V2-SE on the way. I'm not looking back.

I don't have their headphone amp but I do own the Redgum Phono pre stage. I find utterly amazing and perfectly suited to its purpose. The sound is very true. I would give it a serious audition.