Frankly, any I7 cpu, 16g ram with win10 pro or enterprise will do.
With that, make sure you have space to install 2 or 3 harddrives or SSDs. (so this rules out small form factor)
I recommand having 1 drive for the OS, 1 drive for the audio data, 1 drive for vsti (if you use them alot)

I have a very old I7 running in my studio (first rev) and it works like a charm when tracking 18tracks.
You should decide where you go as for audio interface before buying the pc. Both usb and firewire are giving good perfo these days and a firewire card is easy to install.
Although the claretts are not bad units, if you can stretch your budget to RME, antelope or even some UA interfaces, you'll get more stable, durable and better sounding units.
I say so because you said 16 tracks. Not the the clarett can't do it but in the long run, an RME has such better drivers and support, you'd make a better investment.
I use a RME Fireface 800 and still get good results even if this is a more than 10 yo unit...

pcrecord, post: 454053, member: 46460 wrote: Frankly, any I7 cpu, 16g ram with win10 pro or enterprise will do.
With that, make sure you have space to install 2 or 3 harddrives or SSDs. (so this rules out small form factor)
I recommand having 1 drive for the OS, 1 drive for the audio data, 1 drive for vsti (if you use them alot)

I have a very old I7 running in my studio (first rev) and it works like a charm when tracking 18tracks.
You should decide where you go as for audio interface before buying the pc. Both usb and firewire are giving good perfo these days and a firewire card is easy to install.
Although the claretts are not bad units, if you can stretch your budget to RME, antelope or even some UA interfaces, you'll get more stable, durable and better sounding units.
I say so because you said 16 tracks. Not the the clarett can't do it but in the long run, an RME has such better drivers and support, you'd make a better investment.
I use a RME Fireface 800 and still get good results even if this is a more than 10 yo unit...

This is the computer that I got quoted, the motherboard has thunderbolt and I have seen the i5 7600 on prebuilt DAW systems for sale

steppingonmars, post: 454066, member: 34258 wrote: This is the computer that I got quoted, the motherboard has thunderbolt and I have seen the i5 7600 on prebuilt DAW systems for sale

KABYLAKE CORE I5-7600 6M CACHE,4.1GHZ

16GB DDR4, 3200MHZ 2 X 8, BLACK, 1.35V

WD BLACK 500GB SATA 6 GB/S 64MB 7200RPM Hard drive

WD BLUE 1TB SATA 6 GB/S 64MB 7200RPM Hard drive

RADEON RX 550 2GB Dual Graphics Video card

Windows 10 HP

GRAPHITE 230T ATX MID TOWER Case

CX550M 550W 80PLUS BRONZE SEMI MOD Power Supply

DVD-RW

Logitech Keyboard/mouse combo

GIGABYTE GA-Z170X-Ultra Gaming (rev. 1.0) Full size ATX, LGA 1151, USB 3.1/Thunderbolt

Full install and test.

So I contacted focusrite, they don't support thunderbolt on PCs yet, neither does UA. Wondering if I should get a Mac and buy a thunderbolt to PCIe adaptor for my UAD 2 card.Has anyone tried this?

steppingonmars, post: 454095, member: 34258 wrote: So I contacted focusrite, they don't support thunderbolt on PCs yet, neither does UA. Wondering if I should get a Mac and buy a thunderbolt to PCIe adaptor for my UAD 2 card.Has anyone tried this?

I did find out however presonus will support thunderbolt 3 with a thunderbolt 3-2 adaptor

There is no reason to do a fixation on thunderbolt. Many USB and/or firewire interfaces have excellent sound and performances...
A unit like this would be one of my best price/quality choice : http://www.rme-audio.de/en/products/fireface_802.php

pcrecord, post: 454100, member: 46460 wrote: There is no reason to do a fixation on thunderbolt. Many USB and/or firewire interfaces have excellent sound and performances...
A unit like this would be one of my best price/quality choice : http://www.rme-audio.de/en/products/fireface_802.php

Thanks, the only issue with the RME is the lack of preamps. I often record with 12 plus channels in a live situation. I am not sold on thunderbolt either. Are there any usb devices that can be daisy chained and do 16 channels? I know presonus has a mixer that will do 16 channels via firewire, that may be another option.

steppingonmars, post: 454224, member: 34258 wrote: Thanks, the only issue with the RME is the lack of preamps. I often record with 12 plus channels in a live situation. I am not sold on thunderbolt either. Are there any usb devices that can be daisy chained and do 16 channels? I know presonus has a mixer that will do 16 channels via firewire, that may be another option.

Looks like the sapphire pro 40 is firewire and can be daisy chained, however looks pretty low quality case wise

I have a Saffire pro 40, and the sound quality is more than OK, the build quality is OK though. You can get thm cheap nowadays. However, I would opt for a new generation audio interface on USB 3, beause the roundtrip time will be shorter.

steppingonmars, post: 454224, member: 34258 wrote: Thanks, the only issue with the RME is the lack of preamps. I often record with 12 plus channels in a live situation. I am not sold on thunderbolt either. Are there any usb devices that can be daisy chained and do 16 channels?

I run 18 ch at 96khz with my RME Fireface 800.
Most of multiple channel interfaces have ADAT inputs that allow external preamp units.
In my case I use a UA 4-710 which offer 8 converters (4 preamps / 4 lines) But there is many adat preamp units.
On the 4 available line ins I put 4 ISA preamps.

One very populare ADAT unit is the Audient ASP 880 and if you want cheap, the focusrite Octopre.

The Fireface 802 is usb and firewire and have 2 ADAT inputs which can receive 16 ch at 44khz (for a total of 28) and 8 ch at 96khz (for a total of 20).
Of course the 802 only have 4 preamps but the 8 line ins go direct to the converter which makes it ideal if you want to run external preamps.

IF you want a unit with more onboard preamps, check the Antelope zen studio : 12 fine preamps with an extra 8 line input (DB25) and 4 adat I/O
Buy a Zen Studio and an Audient ASP880 gives 20 very nice preamps and still have room to add Highend preamps later.

If those are too expensive for you, you can go cheaper with the Clarett 8pre and an octopre dynamic to have 16 preamps/lines
https://www.sweetwater.com/store/detail/Clarett8PreX
https://www.sweetwater.com/store/detail/ScarOctoPreDy

What DAW platform are you using?