Help in putting together my system with used equipment on Audiogon and eBay.

My $.02: keep the amp and preamp you have for now; spend as much of your budget as you can on good speakers. Spend as much time as you can trying out different speakers before you buy, as the the speaker is the biggest influence on sound, and sound preference is the most personal of choices.

Then build backwards from there with gear that works well with the speakers - i.e. an amp that controls bass well, etc., depending on the speakers, sources, etc.

BTW. Magnepans have amazing bass. It is not SPLs, which you can get from a subwoofer, but rather detailed, real bass sound.

The main point is, speakers are the biggest matter of preference and the most influential in the overall sound. So pick those first, all other gear being "interim," then slowly research and replace components to fit the speakers. Second most influential is source - lossless FLAC or CD being your best digital option. Then amp, then preamp.

Tweaks are a matter of managing your personality/compulsions as much as actually mattering in the sound. Some matter, many don't. YMMV.

imabucfan,

I have a mega system for your money if you go used:

Nuprime MCH-K38 amp $1250 (U)
Audible Illusions 3 preamp $925 (U)     if NOT going analog
VMPS RM30, RM40 speakers $1800-2700 (U)
Modwright Sony 9000, 9100, 5400 CD/SACD player $1000-1500 (U)
Acoustic BBQ cables get the double version ICs $279 each (N)
Acoustic BBQ Duelund speaker cables $379 (N)
VPI Classic turntable/arm $1600-1900 (U)
Clearaudio Virtuoso Wood cartridge $500-600 (U)
Acoustic BBQ power cables $200 each (N)

The last 3 items only if going analog, you would need to get the AI 3A or 3B full function preamp then. $1200-2350 depending on which model (U) instead of the AI 3.

Everything in your system would be absolutely top drawer and sound great together. The AI preamps are tubed and last a LONG time and sound great--very clear and transparent. The phono section in an AI is the equal of most any separate up to $3000 of more.

The Nuprime amp can be bridge to 400 watts per channel at 8 ohms and has a very dynamic, detailed sound, with terrific bass.

VMPS speaker are no longer made, but I’ve owned at least 5 of them--I was a demonstrator for VMPS for 4 years because I asked Brian Cheney if I could be one. The speakers are that impressive. Very detailed, dynamic, transparent, with potent bass.

The Modwright CD players changed my thoughts on CD. They are VERY good sounding in all ways.

I’ve had the combo of analog things I recommended. Work great together and is very good sound for the money.

The BBQ cables are very good sounding with much texture and transparency.

Good luck,
Bob

I can describe my system built on used/vintage components to give you an idea what you can do for few thousand dollars with used equipment.

Speakers: Polk Audio SRS 1.2TL - Yes, Polk but it’s from Polk golden years and true monsters. Mine have almost been totally rebuilt with higher grade crossover components and tweeters than original. I built new crossovers with all new components. Cost maybe around $3000 with upgrades. Many think these speakers are about volume but their true strength is the sound quality and imaging (at all levels). I also have a sub and I would recommend something like an SVS SB-3000 if your room is big.

Amplification: Combridge Audio Azur 851W - This amp delivers 200 wpc in 8 ohms and 350 wpc in the 4. The SRS 1.2TL should be around 4 ohms after the crossover upgrade. Plenty of power. Biased towards class A but runs a bit hot though. Got mine used for about $1000. My original plan was to power the SRS 1.2TL with something like a pair of Parasound JC1 monoblocks or a single JC5. Until then the Azur 851W works just fine.

Preamp-DAC: NAD M51 - Smooth and natural sounding DAC that can be used a preamp. Plenty of inputs. Got mine for about $1000 two years ago and can probably be found for less today. I might have opted for the CA Azur 851N preamp/dac/streamer to match the power amp but like the NAD so much I don’t wan’t to bother.

Streaming: Chromcast Audio & Rasberry Pi with RoPieee image for Roon. Cost almost free. :)

I think what I have hoarded sounds pretty amazing but with $8000 you should be able to get components that are considered more "high-end" than mine. :)

The possibilities are endless! I’d focus on the speakers first. You should have plenty of options if you’re willing to spend $4000-$5000 on used speakers ..802 Nautilus maybe.. Have fun!

I loved my B&W 804 Nautilus for a very long time and compared them with other speakers over the years. I did a trial on a pair of Tekton Double Impact speakers just to see what the fluff-up over Tekton was about. The 3K Tektons were a huge improvement over the 804s. I was so shocked and impressed with what Tekton was doing, I returned the DIs and purchased Ulfberhts. Those are out of your price range but I just wanted to relate this experience from a former, huge B&W fan. Tekton has a free trial period and will only require return freight. They are also extremely efficient and will certainly get loud if that's your thing. I built a Pass B1 Korg preamp and a F5 power amp. The Tektons love Pass too when fed from my turntable. After a long period of trial amplifiers/DACs/etc, for digital I chose a Lyngdorf integrated amp that includes an excellent internal DAC. So you would save the money for that. Just food for thought from my personal direct experience with this hardware. Not rumors on the internet. https://www.tektondesign.com   https://lyngdorf.com/

As the Small Faces song says
" I wish that I knew what I know now when I was younger "

Since you are starting from scratch I'd recommend a tube or hybrid integrated amp , you'll save a lot by not by not having to spend money on interconnects and power cords . 
You have CD's and used ones are very cheap ,
CD players and their DAC chips have come a long way .  
I don't recommend jumping into Vinyl at first , something you could get into if you really love spending time and money on your hobby .
As for speakers , I'd say read Audiogon forums , 
read older copies of The Absolute Sound and Stereophile .

I have Thiel speakers so check out the Thiel Owners audiogon forum .

Good Luck and Happy Listening