I don't know what you will find on YT that will be helpful (I really didn't), but can confirm I love my ABM head. Everything sounds to varying degrees great through it, and it sounds great with any of my 3 cabs. I used a '71 Jazz at rehearsal last night and it was the least impressive of everything I used thus far. I didn't go the the Ampeg head, but going from memory I think it likely sounded a tad better for that bass. May change strings on the Jazz or just use the Ampeg when I want to play it. This is not to say it didn't sound really good. I haven't played every bass though the ABM yet, but I can say I think I could be happy with just it as my main head. My best bass ('64 Thunderbird) sounded almost as good as through the Ampeg and the Ashdown "fixed" a few basses I was not happy with. So, yeah, I think I could live with it only. But won't and will use whichever head I'm in the mood for.