but i have some questions, how can you separate the power amp from the preamp if you are using a head...
why are you using a DI box?...
The diagram shows the Pre Amp and Power Amp SECTIONS of any amp with FX Loop, it doesn´t mean that they are separated "gear".
In the Pre Amp Section you have the Input of the amp and the FX Send to the Power Amp Section. In the Power Amp Section you have the FX Return from the Pre Amp Section.
The concept is that you connect the POD FX Loop to the Pre Amp Section of the amp. Then the POD output straight to the Power Amp Section, so in the POD you have to choose the COMBO OR STACK POWER AMP OUTPUT MODE, depending if you are connected to a head or a combo.
This way, you can insert the FX LOOP Block in the signal chain (managed by the POD), and what you are inserting is the PRE AMP Section of the amp, that´s to say, your amp clean and dirt channels. Then you can add effects in the POD before or after the loop.
If you are just using the models on the POD, you don´t insert the FX LOOP Block in the signal chain, and you have the POD working directly to the Power Amp Section of the amp.
The DI BOX converts an unbalanced signal to a balanced one. I insert it in the signal chain to avoid tone suck produced by the POD´s FX Loop. That is a slippery topic, well discussed in this Forum. You can read JIMSREYNOLDS 4CM Manual, it´s a very good and instructive document.
All this is quite complex, I´m trying to resume here my experience of a year with this method!
I don´t know if this method is right for you, but you have to try it yourself and decide... It depends on if you gig or not, if you don´t mind spending time connecting all, etc.
But one thing is for sure... with this method you have the best of both worlds: your POD modelling, and your stomboxes / amp's channels.
Hope this helps, if you need more info don´t doubt to contact me.