Amp/Preamps vs. High end AV Receivers


Hi,
I am sure this topic had been discussed exhaustively. I am new to this arena looking for some help to upgrade my Onkyo AV Receiver (135 w/channel). I am debating whether to the AV route or the AMP/Preamp combo. Naturally, I understand that I get what I pay for.

Would appreciate some inputs and suggestions regarding:
1. AMP/PREAMP combo route - 
2. AV route

I am not looking at a huge budget but a decent one. 

Thanks in advance
128x128terrancej
Running a similar type setup.  Started upgrading a couple years ago to bring up the sound quality after a downsizing move created the need to compromise from a dedicated room which had 2 Bryston 4B SST amps and ML speakers.  I run a Denon x4300h in 7.1, Magnepan MMG, REL sub, NHT super 0 surrounds.  The Maggies needed more power so I built the Hypex NC400 amps.  Immediate improvement- dark, controlled, no heat in cabinet.  When I use HT mode all is great.  When I switch to vinyl (Rega P3 with Nag 110 cartridge and Parks Puffin pre), Spotify or CD's I put the receiver in pure direct mode and call it a day.  In my little world I couldn't be happier.  
I had an AVR but then went the separates route.  The overall sound is much better, but I don't need to rehash what others have said.  

I got a used 5 channel amp, and added it as an outboard amplifier.  The AVR has line level outputs, and I connected those to the amp.  The advantage of this type of setup is that you can use a cheaper AVR without much power, and you can use the separate amp to power  your speakers.  

Then, in my case, I later wanted to upgrade to support 4K video, and I was able to score a $1k Denon AVR on clearance for less than $600.  It has all the software support I could need for up to 9 channels, including Atmos.  And, I can use the built in amps for the Atmos speakers if I decide later to go that way.  

In your shoes, if your AVR has line output, then I would just get a separate amp.  If it does not, and doesn't meet your codec requirements, then you can get a nice amp for under $1k (I paid $600 for an older 150 wpc Adcom 5 channel amp), and a nice (lower power) AVR under $1k.  In the future, you can meet any software changes with a low cost AVR, and connect it to your nice power amp.  

This option is way better to me than upgrading to a $2k AVR because when you want to update the AVR, you also have to pay the cost of the amps... meaning another $2k investment.  
I like the suggestion of  soundermn. I will probably start by using my AVR pre-out and buy an Amp and then build it from there. 

I will check out some 5 channel or 7 channel amps.