I haven't tried the HD600, so this is just my thoughts on DACs and amplifiers after spending a lot of time on this forum.

> What are your personal opinions and preferences on amps?

For me I would only buy an amp if I NEEDED one. If I'm powering my headphones through my computer and it's not loud enough at maxed out settings for my personal use case, then I'd consider an amp.

> also what exactly is a dac?

A DAC is a digital-audio converter. Basically, it converts the digital signal of the audio, and then converts it into an analog signal, which your headphones can understand and produce audio with. You don't NEED a DAC by any means, but if you're experiencing issues with the source you're using (issues can be things like a hissing noise when there's no music playing), then you can use an external DAC to fix those issues.

> if I ever get an amp it will likely be a combo unit and as budget as possible because I did just spend all my money on a single headphone.

Sure, that's up to you. I want to say that you should try listening to the HD 600 first from your devices without an amp and see if it needs more juice to sound adequately loud, and if it does... you can order either a dedicated amp or a combo DAC + amp unit. (Disclaimer: from reading the HD 600's resistance and sensitivity, I think you'll most likely need an amp) People do say that an amp makes the sound better, but it's usually a very marginal improvement for a lot of money, so it might not be worth it unless you absolutely need it.