HD500X vs Positive Grid Spark in POD HD Posted March 23, 2021 The Spark and the POD HD 500X are similar but very different. Both offer a variety of amps and pedals to craft your sound but this is really where the similarities end. The Spark really shines as a practice tool providing a wide variety of tools to help you learn how to play better. The POD HD shines as a professional effects unit that works well with your Variax. I have not had a Spark but I did have a Variax and a POD HD500 and it was cool how you could include your guitar settings in your POD patch. Personally, I really like combination of the Variax and the POD but this combination really works best with a FRFR speaker like a PA speaker to get the full benefit. TBH, if you really insist on a bedroom tube amp...or any amp for that matter, it won’t necessarily play nice with your POD HD. You would basically be best using only the POD HD for effects and not using the Amp and Cab sims. I hope this helps you a little at least.