How Do I Connect A passive PA System's Amplifier To A Mixer

@coolrekz -

                                 You're welcome.

                            Go make some music!

@rodman99999 Many thanks for the reply.

@imhififan Many thanks for your answer. Is any of your options the better choice and if so why?

Many thanks all.

There are many ways to connect the Behringer X2222USB to The Power Dynamics PDM-805A.

You can use a pair of RCA to 1/4" TS adapters plug into the X2222USB rear panel L and R "MAIN OUTPUTS" and connect it to PDM-805A rear panel "TAPE IN" via RCA cable.

OR

Connect the RCA cable to the PDM-805A front panel "CHANNEL 8" line inputs so you can utilize its control for level, tone and effects.

RCA to 1/4" TS adapters

@coolrekz -

     Close to the left of your PDA's EQ, there is an 1/8" Line In and (slightly further over) a 1/4" Line In.

     The unit's manual is not very comprehensive and doesn't mention whether either are a stereo input and there are no controls (that I can see) for their levels, balance, etc, so: no indication if they are stereo inputs.      

      If the 1/4" Line In is a stereo outlet*: make or buy a two 1/4" Mono to one 1/4" stereo plug cable and connect the Behringer's 1/4" Outs to that Line In.

      *If not: most 1/8" Line Ins are stereo, to facilitate the playing of portable tapes, CDs, etc and you could follow the above idea, but with an 1/8" stereo plug or 1/4" to 1/8" stereo plug adapter.     

      If neither of the PDA's Line Ins are stereo: go from the Behringer's L/R 1/4"  Outputs to both the 1/4" and 1/8" Line Ins with mono cables.

                            Mickey Mouse, but: it should get you there.

https://www.amazon.com/JOLGOO-Stereo-Breakout-6-35mm-Splitter/dp/B082X6618T?th=1

https://www.amazon.com/NANYI-Female-Headphone-Adapter-Upgrade/dp/B07QLGYW3H/ref=sr_1_4?crid=3DYPFTUO7P7D2&keywords=1%2F4+to+1%2F8+stereo+plug&qid=1651240072&s=electronics&sprefix=1%2F4+to+1%2F8+stereo+plug%2Celectronics%2C89&sr=1-4

Not that the loss of two inputs on the pa/amp mixer would matter as i would basically be using the pa/amp mixer to power the speakers and the separate Behringer mixer for all the inputs.

Hi thanks for the answer - when you say the "line in" on the pd amp mixer do you mean two of the inputs on the front that i would normally plug an instrument/mic into?

If so then id lose two of the inputs for instruments on the mixer?

If so would these two inputs on the pa amp/mixer become the main out control?

Well, we don't get a lot of pro gear questions here, but it seems very simple.  Use 1/4" TRS connectors from the Main OUT on the Behringer to your PD amp/mixer using the Lin IN connectors. 

The real problem is you have 2 mixers.  The Behringer and the PD amp both have mixers built in, so you have a lot of extra controls, but this should work.