BT Preamp Setup Question

Hi,

I recently purchased a used Arcam AVR350 to drive my Onix RS450 towers and NHT SW12 sub. Unfortunately the DSP is fried (a common issue with this model) so I need to go analog in and use 'Direct' mode on the receiver which means no ability to equalize. Despite having 130 watts per channel out, I'm finding I need to turn the volume up quite loud to get these 8 ohm speakers to a reasonable volume. Probably because I'm currently feeding the receiver through the headphone jack on my phone which is likely delivering a pretty weak output. I also need to integrate my sub into the mix and I want to add Bluetooth connectivity. Since I can't run the sub from the receiver, the only way I can think to feed both the receiver and sub is to split an RCA and plug one set into the receiver and the other into the line input on the sub.

As an example, one preamp I've been considering is this one.

So the configuration I'm envisioning would look like this:

• plug 3.5mm cable into headphone output on whichever BT preamp I get;
• opposite end of 3.5mm cable is 2 male RCA connections (L/R);
• I've purchased two RCA splitter cables (female in x 2 male out) so I can split the signal to feed two components (sub and receiver);
• plug one set of RCAs into the CD input on the receiver and run it in 'Direct' mode (to bypass any digital processing);
• plug other set of RCAs into line input on sub;
• use preamp for equalization.

*Question: say I get a preamp that does 50W out per channel. Will any of this amplification be delivered to the receiver through the headphone jack so that I don't have to have the receiver volume up so high or would I only see this power by connecting to the speaker outputs on the back of the preamp?

I'm fairly green when it comes to A/V so I may be totally naive in thinking this daisy-chained setup will work. If there is a more elegant / efficient way to accomplish what I'm trying to do given the limitations of not being able to use digital functionality on the receiver I would love to know. Any help / recommendations are greatly appreciated!